280 lines
10 KiB
C
280 lines
10 KiB
C
/*
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** 2009 Nov 12
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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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*/
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#ifndef _FTSINT_H
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#define _FTSINT_H
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#if !defined(NDEBUG) && !defined(SQLITE_DEBUG)
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# define NDEBUG 1
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#endif
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#include "sqlite3.h"
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#include "fts3_tokenizer.h"
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#include "fts3_hash.h"
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/*
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** This constant controls how often segments are merged. Once there are
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** FTS3_MERGE_COUNT segments of level N, they are merged into a single
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** segment of level N+1.
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*/
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#define FTS3_MERGE_COUNT 16
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/*
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** This is the maximum amount of data (in bytes) to store in the
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** Fts3Table.pendingTerms hash table. Normally, the hash table is
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** populated as documents are inserted/updated/deleted in a transaction
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** and used to create a new segment when the transaction is committed.
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** However if this limit is reached midway through a transaction, a new
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** segment is created and the hash table cleared immediately.
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*/
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#define FTS3_MAX_PENDING_DATA (1*1024*1024)
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/*
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** Macro to return the number of elements in an array. SQLite has a
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** similar macro called ArraySize(). Use a different name to avoid
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** a collision when building an amalgamation with built-in FTS3.
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*/
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#define SizeofArray(X) ((int)(sizeof(X)/sizeof(X[0])))
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/*
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** Maximum length of a varint encoded integer. The varint format is different
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** from that used by SQLite, so the maximum length is 10, not 9.
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*/
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#define FTS3_VARINT_MAX 10
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/*
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** This section provides definitions to allow the
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** FTS3 extension to be compiled outside of the
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** amalgamation.
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*/
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#ifndef SQLITE_AMALGAMATION
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/*
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** Macros indicating that conditional expressions are always true or
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** false.
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*/
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# define ALWAYS(x) (x)
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# define NEVER(X) (x)
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/*
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** Internal types used by SQLite.
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*/
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typedef unsigned char u8; /* 1-byte (or larger) unsigned integer */
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typedef short int i16; /* 2-byte (or larger) signed integer */
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/*
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** Macro used to suppress compiler warnings for unused parameters.
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*/
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#define UNUSED_PARAMETER(x) (void)(x)
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#endif
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typedef struct Fts3Table Fts3Table;
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typedef struct Fts3Cursor Fts3Cursor;
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typedef struct Fts3Expr Fts3Expr;
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typedef struct Fts3Phrase Fts3Phrase;
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typedef struct Fts3SegReader Fts3SegReader;
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typedef struct Fts3SegFilter Fts3SegFilter;
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/*
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** A connection to a fulltext index is an instance of the following
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** structure. The xCreate and xConnect methods create an instance
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** of this structure and xDestroy and xDisconnect free that instance.
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** All other methods receive a pointer to the structure as one of their
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** arguments.
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*/
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struct Fts3Table {
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sqlite3_vtab base; /* Base class used by SQLite core */
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sqlite3 *db; /* The database connection */
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const char *zDb; /* logical database name */
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const char *zName; /* virtual table name */
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int nColumn; /* number of named columns in virtual table */
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char **azColumn; /* column names. malloced */
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sqlite3_tokenizer *pTokenizer; /* tokenizer for inserts and queries */
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/* Precompiled statements used by the implementation. Each of these
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** statements is run and reset within a single virtual table API call.
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*/
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sqlite3_stmt *aStmt[18];
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/* Pointer to string containing the SQL:
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**
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** "SELECT block FROM %_segments WHERE blockid BETWEEN ? AND ?
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** ORDER BY blockid"
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*/
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char *zSelectLeaves;
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int nLeavesStmt; /* Valid statements in aLeavesStmt */
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int nLeavesTotal; /* Total number of prepared leaves stmts */
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int nLeavesAlloc; /* Allocated size of aLeavesStmt */
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sqlite3_stmt **aLeavesStmt; /* Array of prepared zSelectLeaves stmts */
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int nNodeSize; /* Soft limit for node size */
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/* The following hash table is used to buffer pending index updates during
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** transactions. Variable nPendingData estimates the memory size of the
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** pending data, including hash table overhead, but not malloc overhead.
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** When nPendingData exceeds FTS3_MAX_PENDING_DATA, the buffer is flushed
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** automatically. Variable iPrevDocid is the docid of the most recently
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** inserted record.
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*/
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int nPendingData;
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sqlite_int64 iPrevDocid;
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Fts3Hash pendingTerms;
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};
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/*
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** When the core wants to read from the virtual table, it creates a
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** virtual table cursor (an instance of the following structure) using
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** the xOpen method. Cursors are destroyed using the xClose method.
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*/
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struct Fts3Cursor {
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sqlite3_vtab_cursor base; /* Base class used by SQLite core */
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i16 eSearch; /* Search strategy (see below) */
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u8 isEof; /* True if at End Of Results */
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u8 isRequireSeek; /* True if must seek pStmt to %_content row */
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sqlite3_stmt *pStmt; /* Prepared statement in use by the cursor */
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Fts3Expr *pExpr; /* Parsed MATCH query string */
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sqlite3_int64 iPrevId; /* Previous id read from aDoclist */
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char *pNextId; /* Pointer into the body of aDoclist */
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char *aDoclist; /* List of docids for full-text queries */
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int nDoclist; /* Size of buffer at aDoclist */
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};
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/*
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** The Fts3Cursor.eSearch member is always set to one of the following.
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** Actualy, Fts3Cursor.eSearch can be greater than or equal to
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** FTS3_FULLTEXT_SEARCH. If so, then Fts3Cursor.eSearch - 2 is the index
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** of the column to be searched. For example, in
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**
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** CREATE VIRTUAL TABLE ex1 USING fts3(a,b,c,d);
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** SELECT docid FROM ex1 WHERE b MATCH 'one two three';
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**
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** Because the LHS of the MATCH operator is 2nd column "b",
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** Fts3Cursor.eSearch will be set to FTS3_FULLTEXT_SEARCH+1. (+0 for a,
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** +1 for b, +2 for c, +3 for d.) If the LHS of MATCH were "ex1"
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** indicating that all columns should be searched,
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** then eSearch would be set to FTS3_FULLTEXT_SEARCH+4.
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*/
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#define FTS3_FULLSCAN_SEARCH 0 /* Linear scan of %_content table */
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#define FTS3_DOCID_SEARCH 1 /* Lookup by rowid on %_content table */
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#define FTS3_FULLTEXT_SEARCH 2 /* Full-text index search */
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/*
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** A "phrase" is a sequence of one or more tokens that must match in
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** sequence. A single token is the base case and the most common case.
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** For a sequence of tokens contained in "...", nToken will be the number
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** of tokens in the string.
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*/
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struct Fts3Phrase {
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int nToken; /* Number of tokens in the phrase */
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int iColumn; /* Index of column this phrase must match */
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int isNot; /* Phrase prefixed by unary not (-) operator */
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struct PhraseToken {
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char *z; /* Text of the token */
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int n; /* Number of bytes in buffer pointed to by z */
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int isPrefix; /* True if token ends in with a "*" character */
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} aToken[1]; /* One entry for each token in the phrase */
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};
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/*
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** A tree of these objects forms the RHS of a MATCH operator.
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*/
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struct Fts3Expr {
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int eType; /* One of the FTSQUERY_XXX values defined below */
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int nNear; /* Valid if eType==FTSQUERY_NEAR */
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Fts3Expr *pParent; /* pParent->pLeft==this or pParent->pRight==this */
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Fts3Expr *pLeft; /* Left operand */
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Fts3Expr *pRight; /* Right operand */
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Fts3Phrase *pPhrase; /* Valid if eType==FTSQUERY_PHRASE */
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};
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/*
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** Candidate values for Fts3Query.eType. Note that the order of the first
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** four values is in order of precedence when parsing expressions. For
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** example, the following:
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**
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** "a OR b AND c NOT d NEAR e"
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**
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** is equivalent to:
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**
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** "a OR (b AND (c NOT (d NEAR e)))"
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*/
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#define FTSQUERY_NEAR 1
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#define FTSQUERY_NOT 2
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#define FTSQUERY_AND 3
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#define FTSQUERY_OR 4
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#define FTSQUERY_PHRASE 5
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/* fts3_init.c */
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int sqlite3Fts3DeleteVtab(int, sqlite3_vtab *);
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int sqlite3Fts3InitVtab(int, sqlite3*, void*, int, const char*const*,
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sqlite3_vtab **, char **);
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/* fts3_write.c */
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int sqlite3Fts3UpdateMethod(sqlite3_vtab*,int,sqlite3_value**,sqlite3_int64*);
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int sqlite3Fts3PendingTermsFlush(Fts3Table *);
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void sqlite3Fts3PendingTermsClear(Fts3Table *);
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int sqlite3Fts3Optimize(Fts3Table *);
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int sqlite3Fts3SegReaderNew(Fts3Table *,int, sqlite3_int64,
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sqlite3_int64, sqlite3_int64, const char *, int, Fts3SegReader**);
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void sqlite3Fts3SegReaderFree(Fts3Table *, Fts3SegReader *);
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int sqlite3Fts3SegReaderIterate(
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Fts3Table *, Fts3SegReader **, int, Fts3SegFilter *,
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int (*)(Fts3Table *, void *, char *, int, char *, int), void *
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);
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int sqlite3Fts3ReadBlock(Fts3Table*, sqlite3_int64, char const**, int*);
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int sqlite3Fts3AllSegdirs(Fts3Table*, sqlite3_stmt **);
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/* Flags allowed as part of the 4th argument to SegmentReaderIterate() */
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#define FTS3_SEGMENT_REQUIRE_POS 0x00000001
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#define FTS3_SEGMENT_IGNORE_EMPTY 0x00000002
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#define FTS3_SEGMENT_COLUMN_FILTER 0x00000004
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#define FTS3_SEGMENT_PREFIX 0x00000008
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/* Type passed as 4th argument to SegmentReaderIterate() */
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struct Fts3SegFilter {
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const char *zTerm;
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int nTerm;
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int iCol;
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int flags;
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};
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/* fts3.c */
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int sqlite3Fts3PutVarint(char *, sqlite3_int64);
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int sqlite3Fts3GetVarint(const char *, sqlite_int64 *);
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int sqlite3Fts3GetVarint32(const char *, int *);
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int sqlite3Fts3VarintLen(sqlite3_uint64);
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void sqlite3Fts3Dequote(char *);
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/* fts3_tokenizer.c */
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const char *sqlite3Fts3NextToken(const char *, int *);
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int sqlite3Fts3InitHashTable(sqlite3 *, Fts3Hash *, const char *);
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int sqlite3Fts3InitTokenizer(Fts3Hash *pHash,
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const char *, sqlite3_tokenizer **, const char **, char **
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);
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/* fts3_snippet.c */
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void sqlite3Fts3Offsets(sqlite3_context*, Fts3Cursor*);
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void sqlite3Fts3Snippet(sqlite3_context*, Fts3Cursor*,
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const char *, const char *, const char *
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);
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/* fts3_expr.c */
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int sqlite3Fts3ExprParse(sqlite3_tokenizer *,
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char **, int, int, const char *, int, Fts3Expr **
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);
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void sqlite3Fts3ExprFree(Fts3Expr *);
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#ifdef SQLITE_TEST
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int sqlite3Fts3ExprInitTestInterface(sqlite3 *db);
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#endif
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#endif /* _FTSINT_H */
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