1383 lines
43 KiB
C
1383 lines
43 KiB
C
/*
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** 2017 July 15
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**
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** The author disclaims copyright to this source code. In place of
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** a legal notice, here is a blessing:
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**
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** May you do good and not evil.
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** May you find forgiveness for yourself and forgive others.
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** May you share freely, never taking more than you give.
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**
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*************************************************************************
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**
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** This file contains the implementation of the "unionvtab" and "swarmvtab"
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** virtual tables. These modules provide read-only access to multiple tables,
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** possibly in multiple database files, via a single database object.
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** The source tables must have the following characteristics:
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**
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** * They must all be rowid tables (not VIRTUAL or WITHOUT ROWID
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** tables or views).
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**
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** * Each table must have the same set of columns, declared in
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** the same order and with the same declared types.
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**
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** * The tables must not feature a user-defined column named "_rowid_".
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**
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** * Each table must contain a distinct range of rowid values.
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**
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** The difference between the two virtual table modules is that for
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** "unionvtab", all source tables must be located in the main database or
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** in databases ATTACHed to the main database by the user. For "swarmvtab",
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** the tables may be located in any database file on disk. The "swarmvtab"
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** implementation takes care of opening and closing database files
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** automatically.
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**
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** UNIONVTAB
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**
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** A "unionvtab" virtual table is created as follows:
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**
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** CREATE VIRTUAL TABLE <name> USING unionvtab(<sql-statement>);
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**
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** The implementation evalutes <sql statement> whenever a unionvtab virtual
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** table is created or opened. It should return one row for each source
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** database table. The four columns required of each row are:
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**
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** 1. The name of the database containing the table ("main" or "temp" or
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** the name of an attached database). Or NULL to indicate that all
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** databases should be searched for the table in the usual fashion.
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**
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** 2. The name of the database table.
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**
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** 3. The smallest rowid in the range of rowids that may be stored in the
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** database table (an integer).
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**
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** 4. The largest rowid in the range of rowids that may be stored in the
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** database table (an integer).
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**
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** SWARMVTAB
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**
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** LEGACY SYNTAX:
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**
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** A "swarmvtab" virtual table is created similarly to a unionvtab table:
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**
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** CREATE VIRTUAL TABLE <name>
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** USING swarmvtab(<sql-statement>, <callback>);
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**
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** The difference is that for a swarmvtab table, the first column returned
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** by the <sql statement> must return a path or URI that can be used to open
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** the database file containing the source table. The <callback> option
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** is optional. If included, it is the name of an application-defined
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** SQL function that is invoked with the URI of the file, if the file
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** does not already exist on disk when required by swarmvtab.
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**
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** NEW SYNTAX:
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**
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** Using the new syntax, a swarmvtab table is created with:
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**
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** CREATE VIRTUAL TABLE <name> USING swarmvtab(
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** <sql-statement> [, <options>]
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** );
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**
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** where valid <options> are:
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**
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** missing=<udf-function-name>
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** openclose=<udf-function-name>
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** maxopen=<integer>
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** <sql-parameter>=<text-value>
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**
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** The <sql-statement> must return the same 4 columns as for a swarmvtab
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** table in legacy mode. However, it may also return a 5th column - the
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** "context" column. The text value returned in this column is not used
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** at all by the swarmvtab implementation, except that it is passed as
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** an additional argument to the two UDF functions that may be invoked
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** (see below).
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**
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** The "missing" option, if present, specifies the name of an SQL UDF
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** function to be invoked if a database file is not already present on
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** disk when required by swarmvtab. If the <sql-statement> did not provide
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** a context column, it is invoked as:
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**
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** SELECT <missing-udf>(<database filename/uri>);
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**
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** Or, if there was a context column:
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**
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** SELECT <missing-udf>(<database filename/uri>, <context>);
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**
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** The "openclose" option may also specify a UDF function. This function
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** is invoked right before swarmvtab opens a database, and right after
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** it closes one. The first argument - or first two arguments, if
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** <sql-statement> supplied the context column - is the same as for
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** the "missing" UDF. Following this, the UDF is passed integer value
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** 0 before a db is opened, and 1 right after it is closed. If both
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** a missing and openclose UDF is supplied, the application should expect
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** the following sequence of calls (for a single database):
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**
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** SELECT <openclose-udf>(<db filename>, <context>, 0);
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** if( db not already on disk ){
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** SELECT <missing-udf>(<db filename>, <context>);
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** }
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** ... swarmvtab uses database ...
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** SELECT <openclose-udf>(<db filename>, <context>, 1);
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**
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** The "maxopen" option is used to configure the maximum number of
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** database files swarmvtab will hold open simultaneously (default 9).
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**
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** If an option name begins with a ":" character, then it is assumed
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** to be an SQL parameter. In this case, the specified text value is
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** bound to the same variable of the <sql-statement> before it is
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** executed. It is an error of the named SQL parameter does not exist.
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** For example:
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**
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** CREATE VIRTUAL TABLE swarm USING swarmvtab(
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** 'SELECT :path || localfile, tbl, min, max FROM swarmdir',
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** :path='/home/user/databases/'
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** missing='missing_func'
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** );
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*/
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#include "sqlite3ext.h"
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SQLITE_EXTENSION_INIT1
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#include <assert.h>
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#include <string.h>
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#include <stdlib.h>
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#ifndef SQLITE_OMIT_VIRTUALTABLE
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/*
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** Largest and smallest possible 64-bit signed integers. These macros
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** copied from sqliteInt.h.
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*/
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#ifndef LARGEST_INT64
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# define LARGEST_INT64 (0xffffffff|(((sqlite3_int64)0x7fffffff)<<32))
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#endif
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#ifndef SMALLEST_INT64
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# define SMALLEST_INT64 (((sqlite3_int64)-1) - LARGEST_INT64)
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#endif
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/*
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** The following is also copied from sqliteInt.h. To facilitate coverage
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** testing.
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*/
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#ifndef ALWAYS
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# if defined(SQLITE_COVERAGE_TEST) || defined(SQLITE_MUTATION_TEST)
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# define ALWAYS(X) (1)
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# define NEVER(X) (0)
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# elif !defined(NDEBUG)
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# define ALWAYS(X) ((X)?1:(assert(0),0))
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# define NEVER(X) ((X)?(assert(0),1):0)
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# else
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# define ALWAYS(X) (X)
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# define NEVER(X) (X)
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# endif
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#endif
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/*
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** The swarmvtab module attempts to keep the number of open database files
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** at or below this limit. This may not be possible if there are too many
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** simultaneous queries.
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*/
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#define SWARMVTAB_MAX_OPEN 9
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typedef struct UnionCsr UnionCsr;
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typedef struct UnionTab UnionTab;
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typedef struct UnionSrc UnionSrc;
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/*
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** Each source table (row returned by the initialization query) is
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** represented by an instance of the following structure stored in the
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** UnionTab.aSrc[] array.
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*/
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struct UnionSrc {
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char *zDb; /* Database containing source table */
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char *zTab; /* Source table name */
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sqlite3_int64 iMin; /* Minimum rowid */
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sqlite3_int64 iMax; /* Maximum rowid */
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/* Fields used by swarmvtab only */
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char *zFile; /* Database file containing table zTab */
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char *zContext; /* Context string, if any */
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int nUser; /* Current number of users */
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sqlite3 *db; /* Database handle */
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UnionSrc *pNextClosable; /* Next in list of closable sources */
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};
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/*
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** Virtual table type for union vtab.
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*/
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struct UnionTab {
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sqlite3_vtab base; /* Base class - must be first */
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sqlite3 *db; /* Database handle */
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int bSwarm; /* 1 for "swarmvtab", 0 for "unionvtab" */
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int iPK; /* INTEGER PRIMARY KEY column, or -1 */
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int nSrc; /* Number of elements in the aSrc[] array */
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UnionSrc *aSrc; /* Array of source tables, sorted by rowid */
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/* Used by swarmvtab only */
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int bHasContext; /* Has context strings */
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char *zSourceStr; /* Expected unionSourceToStr() value */
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sqlite3_stmt *pNotFound; /* UDF to invoke if file not found on open */
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sqlite3_stmt *pOpenClose; /* UDF to invoke on open and close */
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UnionSrc *pClosable; /* First in list of closable sources */
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int nOpen; /* Current number of open sources */
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int nMaxOpen; /* Maximum number of open sources */
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};
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/*
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** Virtual table cursor type for union vtab.
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*/
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struct UnionCsr {
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sqlite3_vtab_cursor base; /* Base class - must be first */
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sqlite3_stmt *pStmt; /* SQL statement to run */
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/* Used by swarmvtab only */
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sqlite3_int64 iMaxRowid; /* Last rowid to visit */
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int iTab; /* Index of table read by pStmt */
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};
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/*
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** Given UnionTab table pTab and UnionSrc object pSrc, return the database
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** handle that should be used to access the table identified by pSrc. This
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** is the main db handle for "unionvtab" tables, or the source-specific
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** handle for "swarmvtab".
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*/
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#define unionGetDb(pTab, pSrc) ((pTab)->bSwarm ? (pSrc)->db : (pTab)->db)
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/*
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** If *pRc is other than SQLITE_OK when this function is called, it
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** always returns NULL. Otherwise, it attempts to allocate and return
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** a pointer to nByte bytes of zeroed memory. If the memory allocation
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** is attempted but fails, NULL is returned and *pRc is set to
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** SQLITE_NOMEM.
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*/
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static void *unionMalloc(int *pRc, sqlite3_int64 nByte){
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void *pRet;
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assert( nByte>0 );
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if( *pRc==SQLITE_OK ){
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pRet = sqlite3_malloc64(nByte);
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if( pRet ){
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memset(pRet, 0, nByte);
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}else{
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*pRc = SQLITE_NOMEM;
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}
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}else{
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pRet = 0;
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}
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return pRet;
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}
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/*
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** If *pRc is other than SQLITE_OK when this function is called, it
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** always returns NULL. Otherwise, it attempts to allocate and return
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** a copy of the nul-terminated string passed as the second argument.
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** If the allocation is attempted but fails, NULL is returned and *pRc is
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** set to SQLITE_NOMEM.
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*/
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static char *unionStrdup(int *pRc, const char *zIn){
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char *zRet = 0;
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if( zIn ){
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sqlite3_int64 nByte = strlen(zIn) + 1;
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zRet = unionMalloc(pRc, nByte);
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if( zRet ){
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memcpy(zRet, zIn, nByte);
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}
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}
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return zRet;
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}
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/*
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** If the first character of the string passed as the only argument to this
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** function is one of the 4 that may be used as an open quote character
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** in SQL, this function assumes that the input is a well-formed quoted SQL
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** string. In this case the string is dequoted in place.
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**
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** If the first character of the input is not an open quote, then this
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** function is a no-op.
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*/
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static void unionDequote(char *z){
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if( z ){
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char q = z[0];
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/* Set stack variable q to the close-quote character */
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if( q=='[' || q=='\'' || q=='"' || q=='`' ){
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int iIn = 1;
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int iOut = 0;
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if( q=='[' ) q = ']';
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while( ALWAYS(z[iIn]) ){
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if( z[iIn]==q ){
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if( z[iIn+1]!=q ){
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/* Character iIn was the close quote. */
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iIn++;
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break;
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}else{
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/* Character iIn and iIn+1 form an escaped quote character. Skip
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** the input cursor past both and copy a single quote character
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** to the output buffer. */
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iIn += 2;
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z[iOut++] = q;
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}
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}else{
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z[iOut++] = z[iIn++];
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}
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}
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z[iOut] = '\0';
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}
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}
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}
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/*
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** This function is a no-op if *pRc is set to other than SQLITE_OK when it
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** is called. NULL is returned in this case.
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**
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** Otherwise, the SQL statement passed as the third argument is prepared
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** against the database handle passed as the second. If the statement is
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** successfully prepared, a pointer to the new statement handle is
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** returned. It is the responsibility of the caller to eventually free the
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** statement by calling sqlite3_finalize(). Alternatively, if statement
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** compilation fails, NULL is returned, *pRc is set to an SQLite error
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** code and *pzErr may be set to an error message buffer allocated by
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** sqlite3_malloc().
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*/
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static sqlite3_stmt *unionPrepare(
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int *pRc, /* IN/OUT: Error code */
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sqlite3 *db, /* Database handle */
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const char *zSql, /* SQL statement to prepare */
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char **pzErr /* OUT: Error message */
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){
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sqlite3_stmt *pRet = 0;
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assert( pzErr );
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if( *pRc==SQLITE_OK ){
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int rc = sqlite3_prepare_v2(db, zSql, -1, &pRet, 0);
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if( rc!=SQLITE_OK ){
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*pzErr = sqlite3_mprintf("sql error: %s", sqlite3_errmsg(db));
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*pRc = rc;
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}
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}
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return pRet;
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}
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/*
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** Like unionPrepare(), except prepare the results of vprintf(zFmt, ...)
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** instead of a constant SQL string.
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*/
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static sqlite3_stmt *unionPreparePrintf(
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int *pRc, /* IN/OUT: Error code */
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char **pzErr, /* OUT: Error message */
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sqlite3 *db, /* Database handle */
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const char *zFmt, /* printf() format string */
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... /* Trailing printf args */
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){
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sqlite3_stmt *pRet = 0;
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char *zSql;
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va_list ap;
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va_start(ap, zFmt);
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zSql = sqlite3_vmprintf(zFmt, ap);
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if( *pRc==SQLITE_OK ){
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if( zSql==0 ){
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*pRc = SQLITE_NOMEM;
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}else{
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pRet = unionPrepare(pRc, db, zSql, pzErr);
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}
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}
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sqlite3_free(zSql);
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va_end(ap);
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return pRet;
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}
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/*
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** Call sqlite3_reset() on SQL statement pStmt. If *pRc is set to
|
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** SQLITE_OK when this function is called, then it is set to the
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** value returned by sqlite3_reset() before this function exits.
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** In this case, *pzErr may be set to point to an error message
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** buffer allocated by sqlite3_malloc().
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*/
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#if 0
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static void unionReset(int *pRc, sqlite3_stmt *pStmt, char **pzErr){
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int rc = sqlite3_reset(pStmt);
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if( *pRc==SQLITE_OK ){
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*pRc = rc;
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if( rc ){
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*pzErr = sqlite3_mprintf("%s", sqlite3_errmsg(sqlite3_db_handle(pStmt)));
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}
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}
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}
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#endif
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/*
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** Call sqlite3_finalize() on SQL statement pStmt. If *pRc is set to
|
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** SQLITE_OK when this function is called, then it is set to the
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** value returned by sqlite3_finalize() before this function exits.
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*/
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static void unionFinalize(int *pRc, sqlite3_stmt *pStmt, char **pzErr){
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sqlite3 *db = sqlite3_db_handle(pStmt);
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int rc = sqlite3_finalize(pStmt);
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if( *pRc==SQLITE_OK ){
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*pRc = rc;
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if( rc ){
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*pzErr = sqlite3_mprintf("%s", sqlite3_errmsg(db));
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}
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}
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}
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|
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/*
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** If an "openclose" UDF was supplied when this virtual table was created,
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** invoke it now. The first argument passed is the name of the database
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** file for source pSrc. The second is integer value bClose.
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**
|
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** If successful, return SQLITE_OK. Otherwise an SQLite error code. In this
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** case if argument pzErr is not NULL, also set (*pzErr) to an English
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** language error message. The caller is responsible for eventually freeing
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** any error message using sqlite3_free().
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*/
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static int unionInvokeOpenClose(
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UnionTab *pTab,
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UnionSrc *pSrc,
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int bClose,
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char **pzErr
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){
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int rc = SQLITE_OK;
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if( pTab->pOpenClose ){
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sqlite3_bind_text(pTab->pOpenClose, 1, pSrc->zFile, -1, SQLITE_STATIC);
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if( pTab->bHasContext ){
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sqlite3_bind_text(pTab->pOpenClose, 2, pSrc->zContext, -1, SQLITE_STATIC);
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}
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sqlite3_bind_int(pTab->pOpenClose, 2+pTab->bHasContext, bClose);
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sqlite3_step(pTab->pOpenClose);
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if( SQLITE_OK!=(rc = sqlite3_reset(pTab->pOpenClose)) ){
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if( pzErr ){
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*pzErr = sqlite3_mprintf("%s", sqlite3_errmsg(pTab->db));
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}
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}
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}
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return rc;
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}
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|
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/*
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|
** This function is a no-op for unionvtab. For swarmvtab, it attempts to
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** close open database files until at most nMax are open. An SQLite error
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|
** code is returned if an error occurs, or SQLITE_OK otherwise.
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*/
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static void unionCloseSources(UnionTab *pTab, int nMax){
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while( pTab->pClosable && pTab->nOpen>nMax ){
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UnionSrc *p;
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UnionSrc **pp;
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for(pp=&pTab->pClosable; (*pp)->pNextClosable; pp=&(*pp)->pNextClosable);
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p = *pp;
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assert( p->db );
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sqlite3_close(p->db);
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p->db = 0;
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*pp = 0;
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pTab->nOpen--;
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unionInvokeOpenClose(pTab, p, 1, 0);
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}
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}
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|
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/*
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** xDisconnect method.
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*/
|
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static int unionDisconnect(sqlite3_vtab *pVtab){
|
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if( pVtab ){
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UnionTab *pTab = (UnionTab*)pVtab;
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int i;
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for(i=0; i<pTab->nSrc; i++){
|
|
UnionSrc *pSrc = &pTab->aSrc[i];
|
|
int bHaveSrcDb = (pSrc->db!=0);
|
|
sqlite3_close(pSrc->db);
|
|
if( bHaveSrcDb ){
|
|
unionInvokeOpenClose(pTab, pSrc, 1, 0);
|
|
}
|
|
sqlite3_free(pSrc->zDb);
|
|
sqlite3_free(pSrc->zTab);
|
|
sqlite3_free(pSrc->zFile);
|
|
sqlite3_free(pSrc->zContext);
|
|
}
|
|
sqlite3_finalize(pTab->pNotFound);
|
|
sqlite3_finalize(pTab->pOpenClose);
|
|
sqlite3_free(pTab->zSourceStr);
|
|
sqlite3_free(pTab->aSrc);
|
|
sqlite3_free(pTab);
|
|
}
|
|
return SQLITE_OK;
|
|
}
|
|
|
|
/*
|
|
** Check that the table identified by pSrc is a rowid table. If not,
|
|
** return SQLITE_ERROR and set (*pzErr) to point to an English language
|
|
** error message. If the table is a rowid table and no error occurs,
|
|
** return SQLITE_OK and leave (*pzErr) unmodified.
|
|
*/
|
|
static int unionIsIntkeyTable(
|
|
sqlite3 *db, /* Database handle */
|
|
UnionSrc *pSrc, /* Source table to test */
|
|
char **pzErr /* OUT: Error message */
|
|
){
|
|
int bPk = 0;
|
|
const char *zType = 0;
|
|
int rc;
|
|
|
|
sqlite3_table_column_metadata(
|
|
db, pSrc->zDb, pSrc->zTab, "_rowid_", &zType, 0, 0, &bPk, 0
|
|
);
|
|
rc = sqlite3_errcode(db);
|
|
if( rc==SQLITE_ERROR
|
|
|| (rc==SQLITE_OK && (!bPk || sqlite3_stricmp("integer", zType)))
|
|
){
|
|
rc = SQLITE_ERROR;
|
|
*pzErr = sqlite3_mprintf("no such rowid table: %s%s%s",
|
|
(pSrc->zDb ? pSrc->zDb : ""),
|
|
(pSrc->zDb ? "." : ""),
|
|
pSrc->zTab
|
|
);
|
|
}
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
** This function is a no-op if *pRc is other than SQLITE_OK when it is
|
|
** called. In this case it returns NULL.
|
|
**
|
|
** Otherwise, this function checks that the source table passed as the
|
|
** second argument (a) exists, (b) is not a view and (c) has a column
|
|
** named "_rowid_" of type "integer" that is the primary key.
|
|
** If this is not the case, *pRc is set to SQLITE_ERROR and NULL is
|
|
** returned.
|
|
**
|
|
** Finally, if the source table passes the checks above, a nul-terminated
|
|
** string describing the column names and types belonging to the source
|
|
** table is returned. Tables with the same set of column names and types
|
|
** cause this function to return identical strings. Is is the responsibility
|
|
** of the caller to free the returned string using sqlite3_free() when
|
|
** it is no longer required.
|
|
*/
|
|
static char *unionSourceToStr(
|
|
int *pRc, /* IN/OUT: Error code */
|
|
UnionTab *pTab, /* Virtual table object */
|
|
UnionSrc *pSrc, /* Source table to test */
|
|
char **pzErr /* OUT: Error message */
|
|
){
|
|
char *zRet = 0;
|
|
if( *pRc==SQLITE_OK ){
|
|
sqlite3 *db = unionGetDb(pTab, pSrc);
|
|
int rc = unionIsIntkeyTable(db, pSrc, pzErr);
|
|
sqlite3_stmt *pStmt = unionPrepare(&rc, db,
|
|
"SELECT group_concat(quote(name) || '.' || quote(type)) "
|
|
"FROM pragma_table_info(?, ?)", pzErr
|
|
);
|
|
if( rc==SQLITE_OK ){
|
|
sqlite3_bind_text(pStmt, 1, pSrc->zTab, -1, SQLITE_STATIC);
|
|
sqlite3_bind_text(pStmt, 2, pSrc->zDb, -1, SQLITE_STATIC);
|
|
if( SQLITE_ROW==sqlite3_step(pStmt) ){
|
|
const char *z = (const char*)sqlite3_column_text(pStmt, 0);
|
|
zRet = unionStrdup(&rc, z);
|
|
}
|
|
unionFinalize(&rc, pStmt, pzErr);
|
|
}
|
|
*pRc = rc;
|
|
}
|
|
|
|
return zRet;
|
|
}
|
|
|
|
/*
|
|
** Check that all configured source tables exist and have the same column
|
|
** names and datatypes. If this is not the case, or if some other error
|
|
** occurs, return an SQLite error code. In this case *pzErr may be set
|
|
** to point to an error message buffer allocated by sqlite3_mprintf().
|
|
** Or, if no problems regarding the source tables are detected and no
|
|
** other error occurs, SQLITE_OK is returned.
|
|
*/
|
|
static int unionSourceCheck(UnionTab *pTab, char **pzErr){
|
|
int rc = SQLITE_OK;
|
|
char *z0 = 0;
|
|
int i;
|
|
|
|
assert( *pzErr==0 );
|
|
z0 = unionSourceToStr(&rc, pTab, &pTab->aSrc[0], pzErr);
|
|
for(i=1; i<pTab->nSrc; i++){
|
|
char *z = unionSourceToStr(&rc, pTab, &pTab->aSrc[i], pzErr);
|
|
if( rc==SQLITE_OK && sqlite3_stricmp(z, z0) ){
|
|
*pzErr = sqlite3_mprintf("source table schema mismatch");
|
|
rc = SQLITE_ERROR;
|
|
}
|
|
sqlite3_free(z);
|
|
}
|
|
sqlite3_free(z0);
|
|
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
** Try to open the swarmvtab database. If initially unable, invoke the
|
|
** not-found callback UDF and then try again.
|
|
*/
|
|
static int unionOpenDatabaseInner(UnionTab *pTab, UnionSrc *pSrc, char **pzErr){
|
|
static const int openFlags = SQLITE_OPEN_READONLY | SQLITE_OPEN_URI;
|
|
int rc;
|
|
|
|
rc = unionInvokeOpenClose(pTab, pSrc, 0, pzErr);
|
|
if( rc!=SQLITE_OK ) return rc;
|
|
|
|
rc = sqlite3_open_v2(pSrc->zFile, &pSrc->db, openFlags, 0);
|
|
if( rc==SQLITE_OK ) return rc;
|
|
if( pTab->pNotFound ){
|
|
sqlite3_close(pSrc->db);
|
|
pSrc->db = 0;
|
|
sqlite3_bind_text(pTab->pNotFound, 1, pSrc->zFile, -1, SQLITE_STATIC);
|
|
if( pTab->bHasContext ){
|
|
sqlite3_bind_text(pTab->pNotFound, 2, pSrc->zContext, -1, SQLITE_STATIC);
|
|
}
|
|
sqlite3_step(pTab->pNotFound);
|
|
if( SQLITE_OK!=(rc = sqlite3_reset(pTab->pNotFound)) ){
|
|
*pzErr = sqlite3_mprintf("%s", sqlite3_errmsg(pTab->db));
|
|
return rc;
|
|
}
|
|
rc = sqlite3_open_v2(pSrc->zFile, &pSrc->db, openFlags, 0);
|
|
}
|
|
if( rc!=SQLITE_OK ){
|
|
*pzErr = sqlite3_mprintf("%s", sqlite3_errmsg(pSrc->db));
|
|
}
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
** This function may only be called for swarmvtab tables. The results of
|
|
** calling it on a unionvtab table are undefined.
|
|
**
|
|
** For a swarmvtab table, this function ensures that source database iSrc
|
|
** is open. If the database is opened successfully and the schema is as
|
|
** expected, or if it is already open when this function is called, SQLITE_OK
|
|
** is returned.
|
|
**
|
|
** Alternatively If an error occurs while opening the databases, or if the
|
|
** database schema is unsuitable, an SQLite error code is returned and (*pzErr)
|
|
** may be set to point to an English language error message. In this case it is
|
|
** the responsibility of the caller to eventually free the error message buffer
|
|
** using sqlite3_free().
|
|
*/
|
|
static int unionOpenDatabase(UnionTab *pTab, int iSrc, char **pzErr){
|
|
int rc = SQLITE_OK;
|
|
UnionSrc *pSrc = &pTab->aSrc[iSrc];
|
|
|
|
assert( pTab->bSwarm && iSrc<pTab->nSrc );
|
|
if( pSrc->db==0 ){
|
|
unionCloseSources(pTab, pTab->nMaxOpen-1);
|
|
rc = unionOpenDatabaseInner(pTab, pSrc, pzErr);
|
|
if( rc==SQLITE_OK ){
|
|
char *z = unionSourceToStr(&rc, pTab, pSrc, pzErr);
|
|
if( rc==SQLITE_OK ){
|
|
if( pTab->zSourceStr==0 ){
|
|
pTab->zSourceStr = z;
|
|
}else{
|
|
if( sqlite3_stricmp(z, pTab->zSourceStr) ){
|
|
*pzErr = sqlite3_mprintf("source table schema mismatch");
|
|
rc = SQLITE_ERROR;
|
|
}
|
|
sqlite3_free(z);
|
|
}
|
|
}
|
|
}
|
|
|
|
if( rc==SQLITE_OK ){
|
|
pSrc->pNextClosable = pTab->pClosable;
|
|
pTab->pClosable = pSrc;
|
|
pTab->nOpen++;
|
|
}else{
|
|
sqlite3_close(pSrc->db);
|
|
pSrc->db = 0;
|
|
unionInvokeOpenClose(pTab, pSrc, 1, 0);
|
|
}
|
|
}
|
|
|
|
return rc;
|
|
}
|
|
|
|
|
|
/*
|
|
** This function is a no-op for unionvtab tables. For swarmvtab, increment
|
|
** the reference count for source table iTab. If the reference count was
|
|
** zero before it was incremented, also remove the source from the closable
|
|
** list.
|
|
*/
|
|
static void unionIncrRefcount(UnionTab *pTab, int iTab){
|
|
if( pTab->bSwarm ){
|
|
UnionSrc *pSrc = &pTab->aSrc[iTab];
|
|
assert( pSrc->nUser>=0 && pSrc->db );
|
|
if( pSrc->nUser==0 ){
|
|
UnionSrc **pp;
|
|
for(pp=&pTab->pClosable; *pp!=pSrc; pp=&(*pp)->pNextClosable);
|
|
*pp = pSrc->pNextClosable;
|
|
pSrc->pNextClosable = 0;
|
|
}
|
|
pSrc->nUser++;
|
|
}
|
|
}
|
|
|
|
/*
|
|
** Finalize the SQL statement pCsr->pStmt and return the result.
|
|
**
|
|
** If this is a swarmvtab table (not unionvtab) and pCsr->pStmt was not
|
|
** NULL when this function was called, also decrement the reference
|
|
** count on the associated source table. If this means the source tables
|
|
** refcount is now zero, add it to the closable list.
|
|
*/
|
|
static int unionFinalizeCsrStmt(UnionCsr *pCsr){
|
|
int rc = SQLITE_OK;
|
|
if( pCsr->pStmt ){
|
|
UnionTab *pTab = (UnionTab*)pCsr->base.pVtab;
|
|
UnionSrc *pSrc = &pTab->aSrc[pCsr->iTab];
|
|
rc = sqlite3_finalize(pCsr->pStmt);
|
|
pCsr->pStmt = 0;
|
|
if( pTab->bSwarm ){
|
|
pSrc->nUser--;
|
|
assert( pSrc->nUser>=0 );
|
|
if( pSrc->nUser==0 ){
|
|
pSrc->pNextClosable = pTab->pClosable;
|
|
pTab->pClosable = pSrc;
|
|
}
|
|
unionCloseSources(pTab, pTab->nMaxOpen);
|
|
}
|
|
}
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
** Return true if the argument is a space, tab, CR or LF character.
|
|
*/
|
|
static int union_isspace(char c){
|
|
return (c==' ' || c=='\n' || c=='\r' || c=='\t');
|
|
}
|
|
|
|
/*
|
|
** Return true if the argument is an alphanumeric character in the
|
|
** ASCII range.
|
|
*/
|
|
static int union_isidchar(char c){
|
|
return ((c>='a' && c<='z') || (c>='A' && c<'Z') || (c>='0' && c<='9'));
|
|
}
|
|
|
|
/*
|
|
** This function is called to handle all arguments following the first
|
|
** (the SQL statement) passed to a swarmvtab (not unionvtab) CREATE
|
|
** VIRTUAL TABLE statement. It may bind parameters to the SQL statement
|
|
** or configure members of the UnionTab object passed as the second
|
|
** argument.
|
|
**
|
|
** Refer to header comments at the top of this file for a description
|
|
** of the arguments parsed.
|
|
**
|
|
** This function is a no-op if *pRc is other than SQLITE_OK when it is
|
|
** called. Otherwise, if an error occurs, *pRc is set to an SQLite error
|
|
** code. In this case *pzErr may be set to point to a buffer containing
|
|
** an English language error message. It is the responsibility of the
|
|
** caller to eventually free the buffer using sqlite3_free().
|
|
*/
|
|
static void unionConfigureVtab(
|
|
int *pRc, /* IN/OUT: Error code */
|
|
UnionTab *pTab, /* Table to configure */
|
|
sqlite3_stmt *pStmt, /* SQL statement to find sources */
|
|
int nArg, /* Number of entries in azArg[] array */
|
|
const char * const *azArg, /* Array of arguments to consider */
|
|
char **pzErr /* OUT: Error message */
|
|
){
|
|
int rc = *pRc;
|
|
int i;
|
|
if( rc==SQLITE_OK ){
|
|
pTab->bHasContext = (sqlite3_column_count(pStmt)>4);
|
|
}
|
|
for(i=0; rc==SQLITE_OK && i<nArg; i++){
|
|
char *zArg = unionStrdup(&rc, azArg[i]);
|
|
if( zArg ){
|
|
int nOpt = 0; /* Size of option name in bytes */
|
|
char *zOpt; /* Pointer to option name */
|
|
char *zVal; /* Pointer to value */
|
|
|
|
unionDequote(zArg);
|
|
zOpt = zArg;
|
|
while( union_isspace(*zOpt) ) zOpt++;
|
|
zVal = zOpt;
|
|
if( *zVal==':' ) zVal++;
|
|
while( union_isidchar(*zVal) ) zVal++;
|
|
nOpt = (int)(zVal-zOpt);
|
|
|
|
while( union_isspace(*zVal) ) zVal++;
|
|
if( *zVal=='=' ){
|
|
zOpt[nOpt] = '\0';
|
|
zVal++;
|
|
while( union_isspace(*zVal) ) zVal++;
|
|
zVal = unionStrdup(&rc, zVal);
|
|
if( zVal ){
|
|
unionDequote(zVal);
|
|
if( zOpt[0]==':' ){
|
|
/* A value to bind to the SQL statement */
|
|
int iParam = sqlite3_bind_parameter_index(pStmt, zOpt);
|
|
if( iParam==0 ){
|
|
*pzErr = sqlite3_mprintf(
|
|
"swarmvtab: no such SQL parameter: %s", zOpt
|
|
);
|
|
rc = SQLITE_ERROR;
|
|
}else{
|
|
rc = sqlite3_bind_text(pStmt, iParam, zVal, -1, SQLITE_TRANSIENT);
|
|
}
|
|
}else if( nOpt==7 && 0==sqlite3_strnicmp(zOpt, "maxopen", 7) ){
|
|
pTab->nMaxOpen = atoi(zVal);
|
|
if( pTab->nMaxOpen<=0 ){
|
|
*pzErr = sqlite3_mprintf("swarmvtab: illegal maxopen value");
|
|
rc = SQLITE_ERROR;
|
|
}
|
|
}else if( nOpt==7 && 0==sqlite3_strnicmp(zOpt, "missing", 7) ){
|
|
if( pTab->pNotFound ){
|
|
*pzErr = sqlite3_mprintf(
|
|
"swarmvtab: duplicate \"missing\" option");
|
|
rc = SQLITE_ERROR;
|
|
}else{
|
|
pTab->pNotFound = unionPreparePrintf(&rc, pzErr, pTab->db,
|
|
"SELECT \"%w\"(?%s)", zVal, pTab->bHasContext ? ",?" : ""
|
|
);
|
|
}
|
|
}else if( nOpt==9 && 0==sqlite3_strnicmp(zOpt, "openclose", 9) ){
|
|
if( pTab->pOpenClose ){
|
|
*pzErr = sqlite3_mprintf(
|
|
"swarmvtab: duplicate \"openclose\" option");
|
|
rc = SQLITE_ERROR;
|
|
}else{
|
|
pTab->pOpenClose = unionPreparePrintf(&rc, pzErr, pTab->db,
|
|
"SELECT \"%w\"(?,?%s)", zVal, pTab->bHasContext ? ",?" : ""
|
|
);
|
|
}
|
|
}else{
|
|
*pzErr = sqlite3_mprintf("swarmvtab: unrecognized option: %s",zOpt);
|
|
rc = SQLITE_ERROR;
|
|
}
|
|
sqlite3_free(zVal);
|
|
}
|
|
}else{
|
|
if( i==0 && nArg==1 ){
|
|
pTab->pNotFound = unionPreparePrintf(&rc, pzErr, pTab->db,
|
|
"SELECT \"%w\"(?)", zArg
|
|
);
|
|
}else{
|
|
*pzErr = sqlite3_mprintf( "swarmvtab: parse error: %s", azArg[i]);
|
|
rc = SQLITE_ERROR;
|
|
}
|
|
}
|
|
sqlite3_free(zArg);
|
|
}
|
|
}
|
|
*pRc = rc;
|
|
}
|
|
|
|
/*
|
|
** xConnect/xCreate method.
|
|
**
|
|
** The argv[] array contains the following:
|
|
**
|
|
** argv[0] -> module name ("unionvtab" or "swarmvtab")
|
|
** argv[1] -> database name
|
|
** argv[2] -> table name
|
|
** argv[3] -> SQL statement
|
|
** argv[4] -> not-found callback UDF name
|
|
*/
|
|
static int unionConnect(
|
|
sqlite3 *db,
|
|
void *pAux,
|
|
int argc, const char *const*argv,
|
|
sqlite3_vtab **ppVtab,
|
|
char **pzErr
|
|
){
|
|
UnionTab *pTab = 0;
|
|
int rc = SQLITE_OK;
|
|
int bSwarm = (pAux==0 ? 0 : 1);
|
|
const char *zVtab = (bSwarm ? "swarmvtab" : "unionvtab");
|
|
|
|
if( sqlite3_stricmp("temp", argv[1]) ){
|
|
/* unionvtab tables may only be created in the temp schema */
|
|
*pzErr = sqlite3_mprintf("%s tables must be created in TEMP schema", zVtab);
|
|
rc = SQLITE_ERROR;
|
|
}else if( argc<4 || (argc>4 && bSwarm==0) ){
|
|
*pzErr = sqlite3_mprintf("wrong number of arguments for %s", zVtab);
|
|
rc = SQLITE_ERROR;
|
|
}else{
|
|
int nAlloc = 0; /* Allocated size of pTab->aSrc[] */
|
|
sqlite3_stmt *pStmt = 0; /* Argument statement */
|
|
char *zArg = unionStrdup(&rc, argv[3]); /* Copy of argument to CVT */
|
|
|
|
/* Prepare the SQL statement. Instead of executing it directly, sort
|
|
** the results by the "minimum rowid" field. This makes it easier to
|
|
** check that there are no rowid range overlaps between source tables
|
|
** and that the UnionTab.aSrc[] array is always sorted by rowid. */
|
|
unionDequote(zArg);
|
|
pStmt = unionPreparePrintf(&rc, pzErr, db,
|
|
"SELECT * FROM (%z) ORDER BY 3", zArg
|
|
);
|
|
|
|
/* Allocate the UnionTab structure */
|
|
pTab = unionMalloc(&rc, sizeof(UnionTab));
|
|
if( pTab ){
|
|
assert( rc==SQLITE_OK );
|
|
pTab->db = db;
|
|
pTab->bSwarm = bSwarm;
|
|
pTab->nMaxOpen = SWARMVTAB_MAX_OPEN;
|
|
}
|
|
|
|
/* Parse other CVT arguments, if any */
|
|
if( bSwarm ){
|
|
unionConfigureVtab(&rc, pTab, pStmt, argc-4, &argv[4], pzErr);
|
|
}
|
|
|
|
/* Iterate through the rows returned by the SQL statement specified
|
|
** as an argument to the CREATE VIRTUAL TABLE statement. */
|
|
while( rc==SQLITE_OK && SQLITE_ROW==sqlite3_step(pStmt) ){
|
|
const char *zDb = (const char*)sqlite3_column_text(pStmt, 0);
|
|
const char *zTab = (const char*)sqlite3_column_text(pStmt, 1);
|
|
sqlite3_int64 iMin = sqlite3_column_int64(pStmt, 2);
|
|
sqlite3_int64 iMax = sqlite3_column_int64(pStmt, 3);
|
|
UnionSrc *pSrc;
|
|
|
|
/* Grow the pTab->aSrc[] array if required. */
|
|
if( nAlloc<=pTab->nSrc ){
|
|
int nNew = nAlloc ? nAlloc*2 : 8;
|
|
UnionSrc *aNew = (UnionSrc*)sqlite3_realloc64(
|
|
pTab->aSrc, nNew*sizeof(UnionSrc)
|
|
);
|
|
if( aNew==0 ){
|
|
rc = SQLITE_NOMEM;
|
|
break;
|
|
}else{
|
|
memset(&aNew[pTab->nSrc], 0, (nNew-pTab->nSrc)*sizeof(UnionSrc));
|
|
pTab->aSrc = aNew;
|
|
nAlloc = nNew;
|
|
}
|
|
}
|
|
|
|
/* Check for problems with the specified range of rowids */
|
|
if( iMax<iMin || (pTab->nSrc>0 && iMin<=pTab->aSrc[pTab->nSrc-1].iMax) ){
|
|
*pzErr = sqlite3_mprintf("rowid range mismatch error");
|
|
rc = SQLITE_ERROR;
|
|
}
|
|
|
|
if( rc==SQLITE_OK ){
|
|
pSrc = &pTab->aSrc[pTab->nSrc++];
|
|
pSrc->zTab = unionStrdup(&rc, zTab);
|
|
pSrc->iMin = iMin;
|
|
pSrc->iMax = iMax;
|
|
if( bSwarm ){
|
|
pSrc->zFile = unionStrdup(&rc, zDb);
|
|
}else{
|
|
pSrc->zDb = unionStrdup(&rc, zDb);
|
|
}
|
|
if( pTab->bHasContext ){
|
|
const char *zContext = (const char*)sqlite3_column_text(pStmt, 4);
|
|
pSrc->zContext = unionStrdup(&rc, zContext);
|
|
}
|
|
}
|
|
}
|
|
unionFinalize(&rc, pStmt, pzErr);
|
|
pStmt = 0;
|
|
|
|
/* It is an error if the SELECT statement returned zero rows. If only
|
|
** because there is no way to determine the schema of the virtual
|
|
** table in this case. */
|
|
if( rc==SQLITE_OK && pTab->nSrc==0 ){
|
|
*pzErr = sqlite3_mprintf("no source tables configured");
|
|
rc = SQLITE_ERROR;
|
|
}
|
|
|
|
/* For unionvtab, verify that all source tables exist and have
|
|
** compatible schemas. For swarmvtab, attach the first database and
|
|
** check that the first table is a rowid table only. */
|
|
if( rc==SQLITE_OK ){
|
|
if( bSwarm ){
|
|
rc = unionOpenDatabase(pTab, 0, pzErr);
|
|
}else{
|
|
rc = unionSourceCheck(pTab, pzErr);
|
|
}
|
|
}
|
|
|
|
/* Compose a CREATE TABLE statement and pass it to declare_vtab() */
|
|
if( rc==SQLITE_OK ){
|
|
UnionSrc *pSrc = &pTab->aSrc[0];
|
|
sqlite3 *tdb = unionGetDb(pTab, pSrc);
|
|
pStmt = unionPreparePrintf(&rc, pzErr, tdb, "SELECT "
|
|
"'CREATE TABLE xyz('"
|
|
" || group_concat(quote(name) || ' ' || type, ', ')"
|
|
" || ')',"
|
|
"max((cid+1) * (type='INTEGER' COLLATE nocase AND pk=1))-1 "
|
|
"FROM pragma_table_info(%Q, ?)",
|
|
pSrc->zTab, pSrc->zDb
|
|
);
|
|
}
|
|
if( rc==SQLITE_OK && SQLITE_ROW==sqlite3_step(pStmt) ){
|
|
const char *zDecl = (const char*)sqlite3_column_text(pStmt, 0);
|
|
rc = sqlite3_declare_vtab(db, zDecl);
|
|
pTab->iPK = sqlite3_column_int(pStmt, 1);
|
|
}
|
|
|
|
unionFinalize(&rc, pStmt, pzErr);
|
|
}
|
|
|
|
if( rc!=SQLITE_OK ){
|
|
unionDisconnect((sqlite3_vtab*)pTab);
|
|
pTab = 0;
|
|
}
|
|
|
|
*ppVtab = (sqlite3_vtab*)pTab;
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
** xOpen
|
|
*/
|
|
static int unionOpen(sqlite3_vtab *p, sqlite3_vtab_cursor **ppCursor){
|
|
UnionCsr *pCsr;
|
|
int rc = SQLITE_OK;
|
|
(void)p; /* Suppress harmless warning */
|
|
pCsr = (UnionCsr*)unionMalloc(&rc, sizeof(UnionCsr));
|
|
*ppCursor = &pCsr->base;
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
** xClose
|
|
*/
|
|
static int unionClose(sqlite3_vtab_cursor *cur){
|
|
UnionCsr *pCsr = (UnionCsr*)cur;
|
|
unionFinalizeCsrStmt(pCsr);
|
|
sqlite3_free(pCsr);
|
|
return SQLITE_OK;
|
|
}
|
|
|
|
/*
|
|
** This function does the work of the xNext() method. Except that, if it
|
|
** returns SQLITE_ROW, it should be called again within the same xNext()
|
|
** method call. See unionNext() for details.
|
|
*/
|
|
static int doUnionNext(UnionCsr *pCsr){
|
|
int rc = SQLITE_OK;
|
|
assert( pCsr->pStmt );
|
|
if( sqlite3_step(pCsr->pStmt)!=SQLITE_ROW ){
|
|
UnionTab *pTab = (UnionTab*)pCsr->base.pVtab;
|
|
rc = unionFinalizeCsrStmt(pCsr);
|
|
if( rc==SQLITE_OK && pTab->bSwarm ){
|
|
pCsr->iTab++;
|
|
if( pCsr->iTab<pTab->nSrc ){
|
|
UnionSrc *pSrc = &pTab->aSrc[pCsr->iTab];
|
|
if( pCsr->iMaxRowid>=pSrc->iMin ){
|
|
/* It is necessary to scan the next table. */
|
|
rc = unionOpenDatabase(pTab, pCsr->iTab, &pTab->base.zErrMsg);
|
|
pCsr->pStmt = unionPreparePrintf(&rc, &pTab->base.zErrMsg, pSrc->db,
|
|
"SELECT rowid, * FROM %Q %s %lld",
|
|
pSrc->zTab,
|
|
(pSrc->iMax>pCsr->iMaxRowid ? "WHERE _rowid_ <=" : "-- "),
|
|
pCsr->iMaxRowid
|
|
);
|
|
if( rc==SQLITE_OK ){
|
|
assert( pCsr->pStmt );
|
|
unionIncrRefcount(pTab, pCsr->iTab);
|
|
rc = SQLITE_ROW;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
** xNext
|
|
*/
|
|
static int unionNext(sqlite3_vtab_cursor *cur){
|
|
int rc;
|
|
do {
|
|
rc = doUnionNext((UnionCsr*)cur);
|
|
}while( rc==SQLITE_ROW );
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
** xColumn
|
|
*/
|
|
static int unionColumn(
|
|
sqlite3_vtab_cursor *cur,
|
|
sqlite3_context *ctx,
|
|
int i
|
|
){
|
|
UnionCsr *pCsr = (UnionCsr*)cur;
|
|
sqlite3_result_value(ctx, sqlite3_column_value(pCsr->pStmt, i+1));
|
|
return SQLITE_OK;
|
|
}
|
|
|
|
/*
|
|
** xRowid
|
|
*/
|
|
static int unionRowid(sqlite3_vtab_cursor *cur, sqlite_int64 *pRowid){
|
|
UnionCsr *pCsr = (UnionCsr*)cur;
|
|
*pRowid = sqlite3_column_int64(pCsr->pStmt, 0);
|
|
return SQLITE_OK;
|
|
}
|
|
|
|
/*
|
|
** xEof
|
|
*/
|
|
static int unionEof(sqlite3_vtab_cursor *cur){
|
|
UnionCsr *pCsr = (UnionCsr*)cur;
|
|
return pCsr->pStmt==0;
|
|
}
|
|
|
|
/*
|
|
** xFilter
|
|
*/
|
|
static int unionFilter(
|
|
sqlite3_vtab_cursor *pVtabCursor,
|
|
int idxNum, const char *idxStr,
|
|
int argc, sqlite3_value **argv
|
|
){
|
|
UnionTab *pTab = (UnionTab*)(pVtabCursor->pVtab);
|
|
UnionCsr *pCsr = (UnionCsr*)pVtabCursor;
|
|
int rc = SQLITE_OK;
|
|
int i;
|
|
char *zSql = 0;
|
|
int bZero = 0;
|
|
|
|
sqlite3_int64 iMin = SMALLEST_INT64;
|
|
sqlite3_int64 iMax = LARGEST_INT64;
|
|
|
|
assert( idxNum==0
|
|
|| idxNum==SQLITE_INDEX_CONSTRAINT_EQ
|
|
|| idxNum==SQLITE_INDEX_CONSTRAINT_LE
|
|
|| idxNum==SQLITE_INDEX_CONSTRAINT_GE
|
|
|| idxNum==SQLITE_INDEX_CONSTRAINT_LT
|
|
|| idxNum==SQLITE_INDEX_CONSTRAINT_GT
|
|
|| idxNum==(SQLITE_INDEX_CONSTRAINT_GE|SQLITE_INDEX_CONSTRAINT_LE)
|
|
);
|
|
|
|
(void)idxStr; /* Suppress harmless warning */
|
|
|
|
if( idxNum==SQLITE_INDEX_CONSTRAINT_EQ ){
|
|
assert( argc==1 );
|
|
iMin = iMax = sqlite3_value_int64(argv[0]);
|
|
}else{
|
|
|
|
if( idxNum & (SQLITE_INDEX_CONSTRAINT_LE|SQLITE_INDEX_CONSTRAINT_LT) ){
|
|
assert( argc>=1 );
|
|
iMax = sqlite3_value_int64(argv[0]);
|
|
if( idxNum & SQLITE_INDEX_CONSTRAINT_LT ){
|
|
if( iMax==SMALLEST_INT64 ){
|
|
bZero = 1;
|
|
}else{
|
|
iMax--;
|
|
}
|
|
}
|
|
}
|
|
|
|
if( idxNum & (SQLITE_INDEX_CONSTRAINT_GE|SQLITE_INDEX_CONSTRAINT_GT) ){
|
|
assert( argc>=1 );
|
|
iMin = sqlite3_value_int64(argv[argc-1]);
|
|
if( idxNum & SQLITE_INDEX_CONSTRAINT_GT ){
|
|
if( iMin==LARGEST_INT64 ){
|
|
bZero = 1;
|
|
}else{
|
|
iMin++;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
unionFinalizeCsrStmt(pCsr);
|
|
if( bZero ){
|
|
return SQLITE_OK;
|
|
}
|
|
|
|
for(i=0; i<pTab->nSrc; i++){
|
|
UnionSrc *pSrc = &pTab->aSrc[i];
|
|
if( iMin>pSrc->iMax || iMax<pSrc->iMin ){
|
|
continue;
|
|
}
|
|
|
|
zSql = sqlite3_mprintf("%z%sSELECT rowid, * FROM %s%q%s%Q"
|
|
, zSql
|
|
, (zSql ? " UNION ALL " : "")
|
|
, (pSrc->zDb ? "'" : "")
|
|
, (pSrc->zDb ? pSrc->zDb : "")
|
|
, (pSrc->zDb ? "'." : "")
|
|
, pSrc->zTab
|
|
);
|
|
if( zSql==0 ){
|
|
rc = SQLITE_NOMEM;
|
|
break;
|
|
}
|
|
|
|
if( iMin==iMax ){
|
|
zSql = sqlite3_mprintf("%z WHERE rowid=%lld", zSql, iMin);
|
|
}else{
|
|
const char *zWhere = "WHERE";
|
|
if( iMin!=SMALLEST_INT64 && iMin>pSrc->iMin ){
|
|
zSql = sqlite3_mprintf("%z WHERE rowid>=%lld", zSql, iMin);
|
|
zWhere = "AND";
|
|
}
|
|
if( iMax!=LARGEST_INT64 && iMax<pSrc->iMax ){
|
|
zSql = sqlite3_mprintf("%z %s rowid<=%lld", zSql, zWhere, iMax);
|
|
}
|
|
}
|
|
|
|
if( pTab->bSwarm ){
|
|
pCsr->iTab = i;
|
|
pCsr->iMaxRowid = iMax;
|
|
rc = unionOpenDatabase(pTab, i, &pTab->base.zErrMsg);
|
|
break;
|
|
}
|
|
}
|
|
|
|
if( zSql==0 ){
|
|
return rc;
|
|
}else{
|
|
sqlite3 *db = unionGetDb(pTab, &pTab->aSrc[pCsr->iTab]);
|
|
pCsr->pStmt = unionPrepare(&rc, db, zSql, &pTab->base.zErrMsg);
|
|
if( pCsr->pStmt ){
|
|
unionIncrRefcount(pTab, pCsr->iTab);
|
|
}
|
|
sqlite3_free(zSql);
|
|
}
|
|
if( rc!=SQLITE_OK ) return rc;
|
|
return unionNext(pVtabCursor);
|
|
}
|
|
|
|
/*
|
|
** xBestIndex.
|
|
**
|
|
** This implementation searches for constraints on the rowid field. EQ,
|
|
** LE, LT, GE and GT are handled.
|
|
**
|
|
** If there is an EQ comparison, then idxNum is set to INDEX_CONSTRAINT_EQ.
|
|
** In this case the only argument passed to xFilter is the rhs of the ==
|
|
** operator.
|
|
**
|
|
** Otherwise, if an LE or LT constraint is found, then the INDEX_CONSTRAINT_LE
|
|
** or INDEX_CONSTRAINT_LT (but not both) bit is set in idxNum. The first
|
|
** argument to xFilter is the rhs of the <= or < operator. Similarly, if
|
|
** an GE or GT constraint is found, then the INDEX_CONSTRAINT_GE or
|
|
** INDEX_CONSTRAINT_GT bit is set in idxNum. The rhs of the >= or > operator
|
|
** is passed as either the first or second argument to xFilter, depending
|
|
** on whether or not there is also a LT|LE constraint.
|
|
*/
|
|
static int unionBestIndex(
|
|
sqlite3_vtab *tab,
|
|
sqlite3_index_info *pIdxInfo
|
|
){
|
|
UnionTab *pTab = (UnionTab*)tab;
|
|
int iEq = -1;
|
|
int iLt = -1;
|
|
int iGt = -1;
|
|
int i;
|
|
|
|
for(i=0; i<pIdxInfo->nConstraint; i++){
|
|
struct sqlite3_index_constraint *p = &pIdxInfo->aConstraint[i];
|
|
if( p->usable && (p->iColumn<0 || p->iColumn==pTab->iPK) ){
|
|
switch( p->op ){
|
|
case SQLITE_INDEX_CONSTRAINT_EQ:
|
|
iEq = i;
|
|
break;
|
|
case SQLITE_INDEX_CONSTRAINT_LE:
|
|
case SQLITE_INDEX_CONSTRAINT_LT:
|
|
iLt = i;
|
|
break;
|
|
case SQLITE_INDEX_CONSTRAINT_GE:
|
|
case SQLITE_INDEX_CONSTRAINT_GT:
|
|
iGt = i;
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
if( iEq>=0 ){
|
|
pIdxInfo->estimatedRows = 1;
|
|
pIdxInfo->idxFlags = SQLITE_INDEX_SCAN_UNIQUE;
|
|
pIdxInfo->estimatedCost = 3.0;
|
|
pIdxInfo->idxNum = SQLITE_INDEX_CONSTRAINT_EQ;
|
|
pIdxInfo->aConstraintUsage[iEq].argvIndex = 1;
|
|
pIdxInfo->aConstraintUsage[iEq].omit = 1;
|
|
}else{
|
|
int iCons = 1;
|
|
int idxNum = 0;
|
|
sqlite3_int64 nRow = 1000000;
|
|
if( iLt>=0 ){
|
|
nRow = nRow / 2;
|
|
pIdxInfo->aConstraintUsage[iLt].argvIndex = iCons++;
|
|
pIdxInfo->aConstraintUsage[iLt].omit = 1;
|
|
idxNum |= pIdxInfo->aConstraint[iLt].op;
|
|
}
|
|
if( iGt>=0 ){
|
|
nRow = nRow / 2;
|
|
pIdxInfo->aConstraintUsage[iGt].argvIndex = iCons++;
|
|
pIdxInfo->aConstraintUsage[iGt].omit = 1;
|
|
idxNum |= pIdxInfo->aConstraint[iGt].op;
|
|
}
|
|
pIdxInfo->estimatedRows = nRow;
|
|
pIdxInfo->estimatedCost = 3.0 * (double)nRow;
|
|
pIdxInfo->idxNum = idxNum;
|
|
}
|
|
|
|
return SQLITE_OK;
|
|
}
|
|
|
|
/*
|
|
** Register the unionvtab virtual table module with database handle db.
|
|
*/
|
|
static int createUnionVtab(sqlite3 *db){
|
|
static sqlite3_module unionModule = {
|
|
0, /* iVersion */
|
|
unionConnect,
|
|
unionConnect,
|
|
unionBestIndex, /* xBestIndex - query planner */
|
|
unionDisconnect,
|
|
unionDisconnect,
|
|
unionOpen, /* xOpen - open a cursor */
|
|
unionClose, /* xClose - close a cursor */
|
|
unionFilter, /* xFilter - configure scan constraints */
|
|
unionNext, /* xNext - advance a cursor */
|
|
unionEof, /* xEof - check for end of scan */
|
|
unionColumn, /* xColumn - read data */
|
|
unionRowid, /* xRowid - read data */
|
|
0, /* xUpdate */
|
|
0, /* xBegin */
|
|
0, /* xSync */
|
|
0, /* xCommit */
|
|
0, /* xRollback */
|
|
0, /* xFindMethod */
|
|
0, /* xRename */
|
|
0, /* xSavepoint */
|
|
0, /* xRelease */
|
|
0, /* xRollbackTo */
|
|
0 /* xShadowName */
|
|
};
|
|
int rc;
|
|
|
|
rc = sqlite3_create_module(db, "unionvtab", &unionModule, 0);
|
|
if( rc==SQLITE_OK ){
|
|
rc = sqlite3_create_module(db, "swarmvtab", &unionModule, (void*)db);
|
|
}
|
|
return rc;
|
|
}
|
|
|
|
#endif /* SQLITE_OMIT_VIRTUALTABLE */
|
|
|
|
#ifdef _WIN32
|
|
__declspec(dllexport)
|
|
#endif
|
|
int sqlite3_unionvtab_init(
|
|
sqlite3 *db,
|
|
char **pzErrMsg,
|
|
const sqlite3_api_routines *pApi
|
|
){
|
|
int rc = SQLITE_OK;
|
|
SQLITE_EXTENSION_INIT2(pApi);
|
|
(void)pzErrMsg; /* Suppress harmless warning */
|
|
#ifndef SQLITE_OMIT_VIRTUALTABLE
|
|
rc = createUnionVtab(db);
|
|
#endif
|
|
return rc;
|
|
}
|