haiku/headers/private/file_systems/QueryParser.h
2011-11-25 06:19:24 +01:00

1603 lines
39 KiB
C++

/*
* Copyright 2001-2009, Axel Dörfler, axeld@pinc-software.de.
* Copyright 2010, Clemens Zeidler <haiku@clemens-zeidler.de>
* Copyright 2011, Ingo Weinhold, ingo_weinhold@gmx.de.
* This file may be used under the terms of the MIT License.
*/
#ifndef _FILE_SYSTEMS_QUERY_PARSER_H
#define _FILE_SYSTEMS_QUERY_PARSER_H
/*! Query parsing and evaluation
The pattern matching is roughly based on code originally written
by J. Kercheval, and on code written by Kenneth Almquist, though
it shares no code.
*/
// The parser has a very static design, but it will do what is required.
//
// ParseOr(), ParseAnd(), ParseEquation() are guarantying the operator
// precedence, that is =,!=,>,<,>=,<= .. && .. ||.
// Apparently, the "!" (not) can only be used with brackets.
//
// If you think that there are too few NULL pointer checks in some places
// of the code, just read the beginning of the query constructor.
// The API is not fully available, just the Query and the Expression class
// are.
#include <dirent.h>
#include <stdlib.h>
#include <string.h>
#include <algorithm>
#include <new>
#include <fs_interface.h>
#include <fs_query.h>
#include <TypeConstants.h>
#include <util/SinglyLinkedList.h>
#include <util/Stack.h>
#include <query_private.h>
#include <lock.h>
#include <file_systems/QueryParserUtils.h>
//#define DEBUG_QUERY
#ifndef QUERY_RETURN_ERROR
# define QUERY_RETURN_ERROR(error) return (error)
#endif
#ifndef QUERY_REPORT_ERROR
# define QUERY_REPORT_ERROR(error) do {} while (false)
#endif
#ifndef QUERY_FATAL
# define QUERY_FATAL(message...) panic(message)
#endif
#ifndef QUERY_INFORM
# define QUERY_INFORM(message...) dprintf(message)
#endif
#ifndef QUERY_D
# define QUERY_D(block)
#endif
namespace QueryParser {
template<typename QueryPolicy> class Equation;
template<typename QueryPolicy> class Expression;
template<typename QueryPolicy> class Term;
template<typename QueryPolicy> class Query;
enum ops {
OP_NONE,
OP_AND,
OP_OR,
OP_EQUATION,
// is only used for invalid equations
OP_EQUAL,
OP_UNEQUAL,
OP_GREATER_THAN,
OP_LESS_THAN,
OP_GREATER_THAN_OR_EQUAL,
OP_LESS_THAN_OR_EQUAL,
};
template<typename QueryPolicy>
union value {
int64 Int64;
uint64 Uint64;
int32 Int32;
uint32 Uint32;
float Float;
double Double;
char String[QueryPolicy::kMaxFileNameLength];
};
template<typename QueryPolicy>
class Query {
public:
typedef typename QueryPolicy::Entry Entry;
typedef typename QueryPolicy::Index Index;
typedef typename QueryPolicy::IndexIterator IndexIterator;
typedef typename QueryPolicy::Node Node;
typedef typename QueryPolicy::Context Context;
public:
Query(Context* context,
Expression<QueryPolicy>* expression,
uint32 flags, port_id port, uint32 token);
~Query();
static status_t Create(Context* context, const char* queryString,
uint32 flags, port_id port, uint32 token,
Query<QueryPolicy>*& _query);
status_t Rewind();
inline status_t GetNextEntry(struct dirent* dirent, size_t size);
void LiveUpdate(Entry* entry, Node* node,
const char* attribute, int32 type,
const uint8* oldKey, size_t oldLength,
const uint8* newKey, size_t newLength);
void LiveUpdateRenameMove(Entry* entry, Node* node,
ino_t oldDirectoryID, const char* oldName,
size_t oldLength, ino_t newDirectoryID,
const char* newName, size_t newLength);
Expression<QueryPolicy>* GetExpression() const
{ return fExpression; }
uint32 Flags() const
{ return fFlags; }
private:
status_t _GetNextEntry(struct dirent* dirent, size_t size);
void _SendEntryNotification(Entry* entry,
status_t (*notify)(port_id, int32, dev_t, ino_t,
const char*, ino_t));
private:
Context* fContext;
Expression<QueryPolicy>* fExpression;
Equation<QueryPolicy>* fCurrent;
IndexIterator* fIterator;
Index fIndex;
Stack<Equation<QueryPolicy>*> fStack;
uint32 fFlags;
port_id fPort;
int32 fToken;
bool fNeedsEntry;
};
/*! Abstract base class for the operator/equation classes.
*/
template<typename QueryPolicy>
class Term {
public:
typedef typename QueryPolicy::Entry Entry;
typedef typename QueryPolicy::Index Index;
typedef typename QueryPolicy::IndexIterator IndexIterator;
typedef typename QueryPolicy::Node Node;
typedef typename QueryPolicy::Context Context;
public:
Term(int8 op) : fOp(op), fParent(NULL) {}
virtual ~Term() {}
int8 Op() const { return fOp; }
void SetParent(Term<QueryPolicy>* parent)
{ fParent = parent; }
Term<QueryPolicy>* Parent() const { return fParent; }
virtual status_t Match(Entry* entry, Node* node,
const char* attribute = NULL, int32 type = 0,
const uint8* key = NULL, size_t size = 0) = 0;
virtual void Complement() = 0;
virtual void CalculateScore(Index& index) = 0;
virtual int32 Score() const = 0;
virtual status_t InitCheck() = 0;
virtual bool NeedsEntry() = 0;
#ifdef DEBUG_QUERY
virtual void PrintToStream() = 0;
#endif
protected:
int8 fOp;
Term<QueryPolicy>* fParent;
};
/*! An Equation object represents an "attribute-equation operator-value" pair.
Although an Equation object is quite independent from the volume on which
the query is run, there are some dependencies that are produced while
querying:
The type/size of the value, the score, and if it has an index or not.
So you could run more than one query on the same volume, but it might return
wrong values when it runs concurrently on another volume.
That's not an issue right now, because we run single-threaded and don't use
queries more than once.
*/
template<typename QueryPolicy>
class Equation : public Term<QueryPolicy> {
public:
typedef typename QueryPolicy::Entry Entry;
typedef typename QueryPolicy::Index Index;
typedef typename QueryPolicy::IndexIterator IndexIterator;
typedef typename QueryPolicy::Node Node;
typedef typename QueryPolicy::Context Context;
public:
Equation(char** expression);
virtual ~Equation();
virtual status_t InitCheck();
status_t ParseQuotedString(char** _start, char** _end);
char* CopyString(char* start, char* end);
virtual status_t Match(Entry* entry, Node* node,
const char* attribute = NULL, int32 type = 0,
const uint8* key = NULL, size_t size = 0);
virtual void Complement();
status_t PrepareQuery(Context* context, Index& index,
IndexIterator** iterator, bool queryNonIndexed);
status_t GetNextMatching(Context* context,
IndexIterator* iterator, struct dirent* dirent,
size_t bufferSize);
virtual void CalculateScore(Index &index);
virtual int32 Score() const { return fScore; }
virtual bool NeedsEntry();
#ifdef DEBUG_QUERY
virtual void PrintToStream();
#endif
private:
Equation(const Equation& other);
Equation& operator=(const Equation& other);
// no implementation
status_t ConvertValue(type_code type);
bool CompareTo(const uint8* value, size_t size);
uint8* Value() const { return (uint8*)&fValue; }
status_t MatchEmptyString();
char* fAttribute;
char* fString;
union value<QueryPolicy> fValue;
type_code fType;
size_t fSize;
bool fIsPattern;
int32 fScore;
bool fHasIndex;
};
/*! The Operator class does not represent a generic operator, but only those
that combine two equations, namely "or", and "and".
*/
template<typename QueryPolicy>
class Operator : public Term<QueryPolicy> {
public:
typedef typename QueryPolicy::Entry Entry;
typedef typename QueryPolicy::Index Index;
typedef typename QueryPolicy::IndexIterator IndexIterator;
typedef typename QueryPolicy::Node Node;
typedef typename QueryPolicy::Context Context;
public:
Operator(Term<QueryPolicy>* left, int8 op,
Term<QueryPolicy>* right);
virtual ~Operator();
Term<QueryPolicy>* Left() const { return fLeft; }
Term<QueryPolicy>* Right() const { return fRight; }
virtual status_t Match(Entry* entry, Node* node,
const char* attribute = NULL, int32 type = 0,
const uint8* key = NULL, size_t size = 0);
virtual void Complement();
virtual void CalculateScore(Index& index);
virtual int32 Score() const;
virtual status_t InitCheck();
virtual bool NeedsEntry();
#ifdef DEBUG_QUERY
virtual void PrintToStream();
#endif
private:
Operator(const Operator& other);
Operator& operator=(const Operator& other);
// no implementation
Term<QueryPolicy>* fLeft;
Term<QueryPolicy>* fRight;
};
template<typename QueryPolicy>
class Expression {
public:
typedef typename QueryPolicy::Entry Entry;
typedef typename QueryPolicy::Index Index;
typedef typename QueryPolicy::IndexIterator IndexIterator;
typedef typename QueryPolicy::Node Node;
typedef typename QueryPolicy::Context Context;
public:
Expression(char* expr);
~Expression();
status_t InitCheck();
const char* Position() const { return fPosition; }
Term<QueryPolicy>* Root() const { return fTerm; }
protected:
Term<QueryPolicy>* ParseOr(char** expr);
Term<QueryPolicy>* ParseAnd(char** expr);
Term<QueryPolicy>* ParseEquation(char** expr);
bool IsOperator(char** expr, char op);
private:
Expression(const Expression& other);
Expression& operator=(const Expression& other);
// no implementation
char* fPosition;
Term<QueryPolicy>* fTerm;
};
// #pragma mark -
template<typename QueryPolicy>
Equation<QueryPolicy>::Equation(char** expr)
:
Term<QueryPolicy>(OP_EQUATION),
fAttribute(NULL),
fString(NULL),
fType(0),
fIsPattern(false)
{
char* string = *expr;
char* start = string;
char* end = NULL;
// Since the equation is the integral part of any query, we're just parsing
// the whole thing here.
// The whitespace at the start is already removed in
// Expression::ParseEquation()
if (*start == '"' || *start == '\'') {
// string is quoted (start has to be on the beginning of a string)
if (ParseQuotedString(&start, &end) < B_OK)
return;
// set string to a valid start of the equation symbol
string = end + 2;
skipWhitespace(&string);
if (*string != '=' && *string != '<' && *string != '>'
&& *string != '!') {
*expr = string;
return;
}
} else {
// search the (in)equation for the actual equation symbol (and for other operators
// in case the equation is malformed)
while (*string && *string != '=' && *string != '<' && *string != '>'
&& *string != '!' && *string != '&' && *string != '|') {
string++;
}
// get the attribute string (and trim whitespace), in case
// the string was not quoted
end = string - 1;
skipWhitespaceReverse(&end, start);
}
// attribute string is empty (which is not allowed)
if (start > end)
return;
// At this point, "start" points to the beginning of the string, "end"
// points to the last character of the string, and "string" points to the
// first character of the equation symbol
// test for the right symbol (as this doesn't need any memory)
switch (*string) {
case '=':
Term<QueryPolicy>::fOp = OP_EQUAL;
break;
case '>':
Term<QueryPolicy>::fOp = *(string + 1) == '='
? OP_GREATER_THAN_OR_EQUAL : OP_GREATER_THAN;
break;
case '<':
Term<QueryPolicy>::fOp = *(string + 1) == '='
? OP_LESS_THAN_OR_EQUAL : OP_LESS_THAN;
break;
case '!':
if (*(string + 1) != '=')
return;
Term<QueryPolicy>::fOp = OP_UNEQUAL;
break;
// any invalid characters will be rejected
default:
*expr = string;
return;
}
// lets change "start" to point to the first character after the symbol
if (*(string + 1) == '=')
string++;
string++;
skipWhitespace(&string);
// allocate & copy the attribute string
fAttribute = CopyString(start, end);
if (fAttribute == NULL)
return;
start = string;
if (*start == '"' || *start == '\'') {
// string is quoted (start has to be on the beginning of a string)
if (ParseQuotedString(&start, &end) < B_OK)
return;
string = end + 2;
skipWhitespace(&string);
} else {
while (*string && *string != '&' && *string != '|' && *string != ')')
string++;
end = string - 1;
skipWhitespaceReverse(&end, start);
}
// at this point, "start" will point to the first character of the value,
// "end" will point to its last character, and "start" to the first non-
// whitespace character after the value string
fString = CopyString(start, end);
if (fString == NULL)
return;
// patterns are only allowed for these operations (and strings)
if (Term<QueryPolicy>::fOp == OP_EQUAL
|| Term<QueryPolicy>::fOp == OP_UNEQUAL) {
fIsPattern = isPattern(fString);
if (fIsPattern && isValidPattern(fString) < B_OK) {
// we only want to have valid patterns; setting fString
// to NULL will cause InitCheck() to fail
free(fString);
fString = NULL;
}
}
*expr = string;
}
template<typename QueryPolicy>
Equation<QueryPolicy>::~Equation()
{
free(fAttribute);
free(fString);
}
template<typename QueryPolicy>
status_t
Equation<QueryPolicy>::InitCheck()
{
if (fAttribute == NULL || fString == NULL
|| Term<QueryPolicy>::fOp == OP_NONE) {
return B_BAD_VALUE;
}
return B_OK;
}
template<typename QueryPolicy>
status_t
Equation<QueryPolicy>::ParseQuotedString(char** _start, char** _end)
{
char* start = *_start;
char quote = *start++;
char* end = start;
for (; *end && *end != quote; end++) {
if (*end == '\\')
end++;
}
if (*end == '\0')
return B_BAD_VALUE;
*_start = start;
*_end = end - 1;
return B_OK;
}
template<typename QueryPolicy>
char*
Equation<QueryPolicy>::CopyString(char* start, char* end)
{
// end points to the last character of the string - and the length
// also has to include the null-termination
int32 length = end + 2 - start;
// just to make sure; since that's the max. attribute name length and
// the max. string in an index, it make sense to have it that way
if (length > QueryPolicy::kMaxFileNameLength || length <= 0)
return NULL;
char* copy = (char*)malloc(length);
if (copy == NULL)
return NULL;
memcpy(copy, start, length - 1);
copy[length - 1] = '\0';
return copy;
}
template<typename QueryPolicy>
status_t
Equation<QueryPolicy>::ConvertValue(type_code type)
{
// Has the type already been converted?
if (type == fType)
return B_OK;
char* string = fString;
switch (type) {
case B_MIME_STRING_TYPE:
type = B_STRING_TYPE;
// supposed to fall through
case B_STRING_TYPE:
strncpy(fValue.String, string, QueryPolicy::kMaxFileNameLength);
fValue.String[QueryPolicy::kMaxFileNameLength - 1] = '\0';
fSize = strlen(fValue.String);
break;
case B_INT32_TYPE:
fValue.Int32 = strtol(string, &string, 0);
fSize = sizeof(int32);
break;
case B_UINT32_TYPE:
fValue.Int32 = strtoul(string, &string, 0);
fSize = sizeof(uint32);
break;
case B_INT64_TYPE:
fValue.Int64 = strtoll(string, &string, 0);
fSize = sizeof(int64);
break;
case B_UINT64_TYPE:
fValue.Uint64 = strtoull(string, &string, 0);
fSize = sizeof(uint64);
break;
case B_FLOAT_TYPE:
fValue.Float = strtod(string, &string);
fSize = sizeof(float);
break;
case B_DOUBLE_TYPE:
fValue.Double = strtod(string, &string);
fSize = sizeof(double);
break;
default:
QUERY_FATAL("query value conversion to 0x%x requested!\n",
(int)type);
// should we fail here or just do a safety int32 conversion?
return B_ERROR;
}
fType = type;
// patterns are only allowed for string types
if (fType != B_STRING_TYPE && fIsPattern)
fIsPattern = false;
return B_OK;
}
/*! Returns true when the key matches the equation. You have to
call ConvertValue() before this one.
*/
template<typename QueryPolicy>
bool
Equation<QueryPolicy>::CompareTo(const uint8* value, size_t size)
{
int32 compare;
// fIsPattern is only true if it's a string type, and fOp OP_EQUAL, or
// OP_UNEQUAL
if (fIsPattern) {
// we have already validated the pattern, so we don't check for failing
// here - if something is broken, and matchString() returns an error,
// we just don't match
compare = matchString(fValue.String, (char*)value) == MATCH_OK ? 0 : 1;
} else
compare = compareKeys(fType, value, size, Value(), fSize);
switch (Term<QueryPolicy>::fOp) {
case OP_EQUAL:
return compare == 0;
case OP_UNEQUAL:
return compare != 0;
case OP_LESS_THAN:
return compare < 0;
case OP_LESS_THAN_OR_EQUAL:
return compare <= 0;
case OP_GREATER_THAN:
return compare > 0;
case OP_GREATER_THAN_OR_EQUAL:
return compare >= 0;
}
QUERY_FATAL("Unknown/Unsupported operation: %d\n", Term<QueryPolicy>::fOp);
return false;
}
template<typename QueryPolicy>
void
Equation<QueryPolicy>::Complement()
{
QUERY_D(if (fOp <= OP_EQUATION || fOp > OP_LESS_THAN_OR_EQUAL) {
QUERY_FATAL("op out of range!\n");
return;
});
int8 complementOp[] = {OP_UNEQUAL, OP_EQUAL, OP_LESS_THAN_OR_EQUAL,
OP_GREATER_THAN_OR_EQUAL, OP_LESS_THAN, OP_GREATER_THAN};
Term<QueryPolicy>::fOp = complementOp[Term<QueryPolicy>::fOp - OP_EQUAL];
}
template<typename QueryPolicy>
status_t
Equation<QueryPolicy>::MatchEmptyString()
{
// There is no matching attribute, we will just bail out if we
// already know that our value is not of a string type.
// If not, it will be converted to a string - and then be compared with "".
// That's why we have to call ConvertValue() here - but it will be
// a cheap call for the next time
// TODO: Should we do this only for OP_UNEQUAL?
if (fType != 0 && fType != B_STRING_TYPE)
return NO_MATCH;
status_t status = ConvertValue(B_STRING_TYPE);
if (status == B_OK)
status = CompareTo((const uint8*)"", fSize) ? MATCH_OK : NO_MATCH;
return status;
}
/*! Matches the node's attribute value with the equation.
Returns MATCH_OK if it matches, NO_MATCH if not, < 0 if something went
wrong.
*/
template<typename QueryPolicy>
status_t
Equation<QueryPolicy>::Match(Entry* entry, Node* node,
const char* attributeName, int32 type, const uint8* key, size_t size)
{
// get a pointer to the attribute in question
union value<QueryPolicy> value;
uint8* buffer = (uint8*)&value;
// first, check if we are matching for a live query and use that value
if (attributeName != NULL && !strcmp(fAttribute, attributeName)) {
if (key == NULL) {
if (type == B_STRING_TYPE)
return MatchEmptyString();
return NO_MATCH;
}
buffer = const_cast<uint8*>(key);
} else if (!strcmp(fAttribute, "name")) {
// if not, check for "fake" attributes ("name", "size", "last_modified")
if (entry == NULL)
return B_ERROR;
buffer = (uint8*)QueryPolicy::EntryGetNameNoCopy(entry, buffer,
sizeof(value));
if (buffer == NULL)
return B_ERROR;
type = B_STRING_TYPE;
size = strlen((const char*)buffer);
} else if (!strcmp(fAttribute, "size")) {
value.Int64 = QueryPolicy::NodeGetSize(node);
type = B_INT64_TYPE;
} else if (!strcmp(fAttribute, "last_modified")) {
value.Int32 = QueryPolicy::NodeGetLastModifiedTime(node);
type = B_INT32_TYPE;
} else {
// then for attributes
if (QueryPolicy::NodeGetAttribute(node, fAttribute, buffer, &size,
&type) != B_OK) {
return MatchEmptyString();
}
}
// prepare own value for use, if it is possible to convert it
status_t status = ConvertValue(type);
if (status == B_OK)
status = CompareTo(buffer, size) ? MATCH_OK : NO_MATCH;
QUERY_RETURN_ERROR(status);
}
template<typename QueryPolicy>
void
Equation<QueryPolicy>::CalculateScore(Index &index)
{
// As always, these values could be tuned and refined.
// And the code could also need some real world testing :-)
// do we have to operate on a "foreign" index?
if (Term<QueryPolicy>::fOp == OP_UNEQUAL
|| QueryPolicy::IndexSetTo(index, fAttribute) < B_OK) {
fScore = 0;
return;
}
// if we have a pattern, how much does it help our search?
if (fIsPattern)
fScore = getFirstPatternSymbol(fString) << 3;
else {
// Score by operator
if (Term<QueryPolicy>::fOp == OP_EQUAL) {
// higher than pattern="255 chars+*"
fScore = 2048;
} else {
// the pattern search is regarded cheaper when you have at
// least one character to set your index to
fScore = 5;
}
}
// take index size into account
fScore = QueryPolicy::IndexGetWeightedScore(index, fScore);
}
template<typename QueryPolicy>
status_t
Equation<QueryPolicy>::PrepareQuery(Context* /*context*/, Index& index,
IndexIterator** iterator, bool queryNonIndexed)
{
status_t status = QueryPolicy::IndexSetTo(index, fAttribute);
// if we should query attributes without an index, we can just proceed here
if (status != B_OK && !queryNonIndexed)
return B_ENTRY_NOT_FOUND;
type_code type;
// Special case for OP_UNEQUAL - it will always operate through the whole
// index but we need the call to the original index to get the correct type
if (status != B_OK || Term<QueryPolicy>::fOp == OP_UNEQUAL) {
// Try to get an index that holds all files (name)
// Also sets the default type for all attributes without index
// to string.
type = status < B_OK ? B_STRING_TYPE : QueryPolicy::IndexGetType(index);
if (QueryPolicy::IndexSetTo(index, "name") != B_OK)
return B_ENTRY_NOT_FOUND;
fHasIndex = false;
} else {
fHasIndex = true;
type = QueryPolicy::IndexGetType(index);
}
if (ConvertValue(type) < B_OK)
return B_BAD_VALUE;
*iterator = QueryPolicy::IndexCreateIterator(index);
if (*iterator == NULL)
return B_NO_MEMORY;
if ((Term<QueryPolicy>::fOp == OP_EQUAL
|| Term<QueryPolicy>::fOp == OP_GREATER_THAN
|| Term<QueryPolicy>::fOp == OP_GREATER_THAN_OR_EQUAL || fIsPattern)
&& fHasIndex) {
// set iterator to the exact position
int32 keySize = QueryPolicy::IndexGetKeySize(index);
// At this point, fIsPattern is only true if it's a string type, and fOp
// is either OP_EQUAL or OP_UNEQUAL
if (fIsPattern) {
// let's see if we can use the beginning of the key for positioning
// the iterator and adjust the key size; if not, just leave the
// iterator at the start and return success
keySize = getFirstPatternSymbol(fString);
if (keySize <= 0)
return B_OK;
}
if (keySize == 0) {
// B_STRING_TYPE doesn't have a fixed length, so it was set
// to 0 before - we compute the correct value here
if (fType == B_STRING_TYPE) {
keySize = strlen(fValue.String);
// The empty string is a special case - we normally don't check
// for the trailing null byte, in the case for the empty string
// we do it explicitly, because there can't be keys in the
// B+tree with a length of zero
if (keySize == 0)
keySize = 1;
} else
QUERY_RETURN_ERROR(B_ENTRY_NOT_FOUND);
}
status = QueryPolicy::IndexIteratorFind(*iterator, Value(), keySize);
if (Term<QueryPolicy>::fOp == OP_EQUAL && !fIsPattern)
return status;
else if (status == B_ENTRY_NOT_FOUND
&& (fIsPattern || Term<QueryPolicy>::fOp == OP_GREATER_THAN
|| Term<QueryPolicy>::fOp == OP_GREATER_THAN_OR_EQUAL))
return B_OK;
QUERY_RETURN_ERROR(status);
}
return B_OK;
}
template<typename QueryPolicy>
status_t
Equation<QueryPolicy>::GetNextMatching(Context* context,
IndexIterator* iterator, struct dirent* dirent, size_t bufferSize)
{
while (true) {
union value<QueryPolicy> indexValue;
size_t keyLength;
Entry* entry = NULL;
status_t status = QueryPolicy::IndexIteratorGetNextEntry(iterator,
&indexValue, &keyLength, (size_t)sizeof(indexValue), &entry);
if (status != B_OK)
return status;
// only compare against the index entry when this is the correct
// index for the equation
if (fHasIndex && !CompareTo((uint8*)&indexValue, keyLength)) {
// They aren't equal? Let the operation decide what to do. Since
// we always start at the beginning of the index (or the correct
// position), only some needs to be stopped if the entry doesn't
// fit.
if (Term<QueryPolicy>::fOp == OP_LESS_THAN
|| Term<QueryPolicy>::fOp == OP_LESS_THAN_OR_EQUAL
|| (Term<QueryPolicy>::fOp == OP_EQUAL && !fIsPattern))
return B_ENTRY_NOT_FOUND;
continue;
}
// TODO: check user permissions here - but which one?!
// we could filter out all those where we don't have
// read access... (we should check for every parent
// directory if the X_OK is allowed)
// Although it's quite expensive to open all parents,
// it's likely that the application that runs the
// query will do something similar (and we don't have
// to do it for root, either).
// go up in the tree until a &&-operator is found, and check if the
// node matches with the rest of the expression - we don't have to
// check ||-operators for that
Term<QueryPolicy>* term = this;
status = MATCH_OK;
if (!fHasIndex)
status = Match(entry, QueryPolicy::EntryGetNode(entry));
while (term != NULL && status == MATCH_OK) {
Operator<QueryPolicy>* parent
= (Operator<QueryPolicy>*)term->Parent();
if (parent == NULL)
break;
if (parent->Op() == OP_AND) {
// choose the other child of the parent
Term<QueryPolicy>* other = parent->Right();
if (other == term)
other = parent->Left();
if (other == NULL) {
QUERY_FATAL("&&-operator has only one child... "
"(parent = %p)\n", parent);
break;
}
status = other->Match(entry, QueryPolicy::EntryGetNode(entry));
if (status < 0) {
QUERY_REPORT_ERROR(status);
status = NO_MATCH;
}
}
term = (Term<QueryPolicy>*)parent;
}
if (status == MATCH_OK) {
ssize_t nameLength = QueryPolicy::EntryGetName(entry,
dirent->d_name,
(const char*)dirent + bufferSize - dirent->d_name);
if (nameLength < 0)
QUERY_RETURN_ERROR(nameLength);
dirent->d_dev = QueryPolicy::ContextGetVolumeID(context);
dirent->d_ino = QueryPolicy::EntryGetNodeID(entry);
dirent->d_pdev = dirent->d_dev;
dirent->d_pino = QueryPolicy::EntryGetParentID(entry);
dirent->d_reclen = sizeof(struct dirent) + strlen(dirent->d_name);
}
if (status == MATCH_OK)
return B_OK;
}
QUERY_RETURN_ERROR(B_ERROR);
}
template<typename QueryPolicy>
bool
Equation<QueryPolicy>::NeedsEntry()
{
return strcmp(fAttribute, "name") == 0;
}
// #pragma mark -
template<typename QueryPolicy>
Operator<QueryPolicy>::Operator(Term<QueryPolicy>* left, int8 op,
Term<QueryPolicy>* right)
:
Term<QueryPolicy>(op),
fLeft(left),
fRight(right)
{
if (left)
left->SetParent(this);
if (right)
right->SetParent(this);
}
template<typename QueryPolicy>
Operator<QueryPolicy>::~Operator()
{
delete fLeft;
delete fRight;
}
template<typename QueryPolicy>
status_t
Operator<QueryPolicy>::Match(Entry* entry, Node* node, const char* attribute,
int32 type, const uint8* key, size_t size)
{
if (Term<QueryPolicy>::fOp == OP_AND) {
status_t status = fLeft->Match(entry, node, attribute, type, key,
size);
if (status != MATCH_OK)
return status;
return fRight->Match(entry, node, attribute, type, key, size);
} else {
// choose the term with the better score for OP_OR
Term<QueryPolicy>* first;
Term<QueryPolicy>* second;
if (fRight->Score() > fLeft->Score()) {
first = fLeft;
second = fRight;
} else {
first = fRight;
second = fLeft;
}
status_t status = first->Match(entry, node, attribute, type, key,
size);
if (status != NO_MATCH)
return status;
return second->Match(entry, node, attribute, type, key, size);
}
}
template<typename QueryPolicy>
void
Operator<QueryPolicy>::Complement()
{
if (Term<QueryPolicy>::fOp == OP_AND)
Term<QueryPolicy>::fOp = OP_OR;
else
Term<QueryPolicy>::fOp = OP_AND;
fLeft->Complement();
fRight->Complement();
}
template<typename QueryPolicy>
void
Operator<QueryPolicy>::CalculateScore(Index &index)
{
fLeft->CalculateScore(index);
fRight->CalculateScore(index);
}
template<typename QueryPolicy>
int32
Operator<QueryPolicy>::Score() const
{
if (Term<QueryPolicy>::fOp == OP_AND) {
// return the one with the better score
if (fRight->Score() > fLeft->Score())
return fRight->Score();
return fLeft->Score();
}
// for OP_OR, be honest, and return the one with the worse score
if (fRight->Score() < fLeft->Score())
return fRight->Score();
return fLeft->Score();
}
template<typename QueryPolicy>
status_t
Operator<QueryPolicy>::InitCheck()
{
if ((Term<QueryPolicy>::fOp != OP_AND && Term<QueryPolicy>::fOp != OP_OR)
|| fLeft == NULL || fLeft->InitCheck() < B_OK
|| fRight == NULL || fRight->InitCheck() < B_OK)
return B_ERROR;
return B_OK;
}
template<typename QueryPolicy>
bool
Operator<QueryPolicy>::NeedsEntry()
{
return ((fLeft && fLeft->NeedsEntry()) || (fRight && fRight->NeedsEntry()));
}
// #pragma mark -
#ifdef DEBUG_QUERY
template<typename QueryPolicy>
void
Operator<QueryPolicy>::PrintToStream()
{
D(__out("( "));
if (fLeft != NULL)
fLeft->PrintToStream();
const char* op;
switch (Term<QueryPolicy>::fOp) {
case OP_OR: op = "OR"; break;
case OP_AND: op = "AND"; break;
default: op = "?"; break;
}
D(__out(" %s ", op));
if (fRight != NULL)
fRight->PrintToStream();
D(__out(" )"));
}
template<typename QueryPolicy>
void
Equation<QueryPolicy>::PrintToStream()
{
const char* symbol = "???";
switch (Term<QueryPolicy>::fOp) {
case OP_EQUAL: symbol = "=="; break;
case OP_UNEQUAL: symbol = "!="; break;
case OP_GREATER_THAN: symbol = ">"; break;
case OP_GREATER_THAN_OR_EQUAL: symbol = ">="; break;
case OP_LESS_THAN: symbol = "<"; break;
case OP_LESS_THAN_OR_EQUAL: symbol = "<="; break;
}
D(__out("[\"%s\" %s \"%s\"]", fAttribute, symbol, fString));
}
#endif // DEBUG_QUERY
// #pragma mark -
template<typename QueryPolicy>
Expression<QueryPolicy>::Expression(char* expr)
{
if (expr == NULL)
return;
fTerm = ParseOr(&expr);
if (fTerm != NULL && fTerm->InitCheck() < B_OK) {
QUERY_FATAL("Corrupt tree in expression!\n");
delete fTerm;
fTerm = NULL;
}
QUERY_D(if (fTerm != NULL) {
fTerm->PrintToStream();
D(__out("\n"));
if (*expr != '\0')
PRINT(("Unexpected end of string: \"%s\"!\n", expr));
});
fPosition = expr;
}
template<typename QueryPolicy>
Expression<QueryPolicy>::~Expression()
{
delete fTerm;
}
template<typename QueryPolicy>
Term<QueryPolicy>*
Expression<QueryPolicy>::ParseEquation(char** expr)
{
skipWhitespace(expr);
bool _not = false;
if (**expr == '!') {
skipWhitespace(expr, 1);
if (**expr != '(')
return NULL;
_not = true;
}
if (**expr == ')') {
// shouldn't be handled here
return NULL;
} else if (**expr == '(') {
skipWhitespace(expr, 1);
Term<QueryPolicy>* term = ParseOr(expr);
skipWhitespace(expr);
if (**expr != ')') {
delete term;
return NULL;
}
// If the term is negated, we just complement the tree, to get
// rid of the not, a.k.a. DeMorgan's Law.
if (_not)
term->Complement();
skipWhitespace(expr, 1);
return term;
}
Equation<QueryPolicy>* equation
= new(std::nothrow) Equation<QueryPolicy>(expr);
if (equation == NULL || equation->InitCheck() < B_OK) {
delete equation;
return NULL;
}
return equation;
}
template<typename QueryPolicy>
Term<QueryPolicy>*
Expression<QueryPolicy>::ParseAnd(char** expr)
{
Term<QueryPolicy>* left = ParseEquation(expr);
if (left == NULL)
return NULL;
while (IsOperator(expr, '&')) {
Term<QueryPolicy>* right = ParseAnd(expr);
Term<QueryPolicy>* newParent = NULL;
if (right == NULL
|| (newParent = new(std::nothrow) Operator<QueryPolicy>(left,
OP_AND, right)) == NULL) {
delete left;
delete right;
return NULL;
}
left = newParent;
}
return left;
}
template<typename QueryPolicy>
Term<QueryPolicy>*
Expression<QueryPolicy>::ParseOr(char** expr)
{
Term<QueryPolicy>* left = ParseAnd(expr);
if (left == NULL)
return NULL;
while (IsOperator(expr, '|')) {
Term<QueryPolicy>* right = ParseAnd(expr);
Term<QueryPolicy>* newParent = NULL;
if (right == NULL
|| (newParent = new(std::nothrow) Operator<QueryPolicy>(left, OP_OR,
right)) == NULL) {
delete left;
delete right;
return NULL;
}
left = newParent;
}
return left;
}
template<typename QueryPolicy>
bool
Expression<QueryPolicy>::IsOperator(char** expr, char op)
{
char* string = *expr;
if (*string == op && *(string + 1) == op) {
*expr += 2;
return true;
}
return false;
}
template<typename QueryPolicy>
status_t
Expression<QueryPolicy>::InitCheck()
{
if (fTerm == NULL)
return B_BAD_VALUE;
return B_OK;
}
// #pragma mark -
template<typename QueryPolicy>
Query<QueryPolicy>::Query(Context* context, Expression<QueryPolicy>* expression,
uint32 flags, port_id port, uint32 token)
:
fContext(context),
fExpression(expression),
fCurrent(NULL),
fIterator(NULL),
fIndex(context),
fFlags(flags),
fPort(port),
fToken(token),
fNeedsEntry(false)
{
// If the expression has a valid root pointer, the whole tree has
// already passed the sanity check, so that we don't have to check
// every pointer
if (context == NULL || expression == NULL || expression->Root() == NULL)
return;
// create index on the stack and delete it afterwards
fExpression->Root()->CalculateScore(fIndex);
QueryPolicy::IndexUnset(fIndex);
fNeedsEntry = fExpression->Root()->NeedsEntry();
Rewind();
}
template<typename QueryPolicy>
Query<QueryPolicy>::~Query()
{
delete fExpression;
}
template<typename QueryPolicy>
/*static*/ status_t
Query<QueryPolicy>::Create(Context* context, const char* queryString,
uint32 flags, port_id port, uint32 token, Query<QueryPolicy>*& _query)
{
Expression<QueryPolicy>* expression
= new(std::nothrow) Expression<QueryPolicy>((char*)queryString);
if (expression == NULL)
QUERY_RETURN_ERROR(B_NO_MEMORY);
if (expression->InitCheck() != B_OK) {
QUERY_INFORM("Could not parse query \"%s\", stopped at: \"%s\"\n",
queryString, expression->Position());
delete expression;
QUERY_RETURN_ERROR(B_BAD_VALUE);
}
Query<QueryPolicy>* query = new(std::nothrow) Query<QueryPolicy>(context,
expression, flags, port, token);
if (query == NULL) {
delete expression;
QUERY_RETURN_ERROR(B_NO_MEMORY);
}
_query = query;
return B_OK;
}
template<typename QueryPolicy>
status_t
Query<QueryPolicy>::Rewind()
{
// free previous stuff
fStack.MakeEmpty();
QueryPolicy::IndexIteratorDelete(fIterator);
fIterator = NULL;
fCurrent = NULL;
// put the whole expression on the stack
Stack<Term<QueryPolicy>*> stack;
stack.Push(fExpression->Root());
Term<QueryPolicy>* term;
while (stack.Pop(&term)) {
if (term->Op() < OP_EQUATION) {
Operator<QueryPolicy>* op = (Operator<QueryPolicy>*)term;
if (op->Op() == OP_OR) {
stack.Push(op->Left());
stack.Push(op->Right());
} else {
// For OP_AND, we can use the scoring system to decide which
// path to add
if (op->Right()->Score() > op->Left()->Score())
stack.Push(op->Right());
else
stack.Push(op->Left());
}
} else if (term->Op() == OP_EQUATION
|| fStack.Push((Equation<QueryPolicy>*)term) != B_OK)
QUERY_FATAL("Unknown term on stack or stack error\n");
}
return B_OK;
}
template<typename QueryPolicy>
status_t
Query<QueryPolicy>::GetNextEntry(struct dirent* dirent, size_t size)
{
if (fIterator != NULL)
QueryPolicy::IndexIteratorResume(fIterator);
status_t error = _GetNextEntry(dirent, size);
if (fIterator != NULL)
QueryPolicy::IndexIteratorSuspend(fIterator);
return error;
}
template<typename QueryPolicy>
void
Query<QueryPolicy>::LiveUpdate(Entry* entry, Node* node, const char* attribute,
int32 type, const uint8* oldKey, size_t oldLength, const uint8* newKey,
size_t newLength)
{
if (fPort < 0 || fExpression == NULL || attribute == NULL)
return;
// TODO: check if the attribute is part of the query at all...
// If no entry has been supplied, but the we need one for the evaluation
// (i.e. the "name" attribute is used), we invoke ourselves for all entries
// referring to the given node.
if (entry == NULL && fNeedsEntry) {
entry = QueryPolicy::NodeGetFirstReferrer(node);
while (entry) {
LiveUpdate(entry, node, attribute, type, oldKey, oldLength, newKey,
newLength);
entry = QueryPolicy::NodeGetNextReferrer(node, entry);
}
return;
}
status_t oldStatus = fExpression->Root()->Match(entry, node, attribute,
type, oldKey, oldLength);
status_t newStatus = fExpression->Root()->Match(entry, node, attribute,
type, newKey, newLength);
bool entryCreated = false;
bool stillInQuery = false;
if (oldStatus != MATCH_OK) {
if (newStatus != MATCH_OK) {
// nothing has changed
return;
}
entryCreated = true;
} else if (newStatus != MATCH_OK) {
// entry got removed
entryCreated = false;
} else if ((fFlags & B_ATTR_CHANGE_NOTIFICATION) != 0) {
// The entry stays in the query
stillInQuery = true;
} else
return;
// notify query listeners
status_t (*notify)(port_id, int32, dev_t, ino_t, const char*, ino_t);
if (stillInQuery)
notify = notify_query_attr_changed;
else if (entryCreated)
notify = notify_query_entry_created;
else
notify = notify_query_entry_removed;
if (entry != NULL) {
_SendEntryNotification(entry, notify);
} else {
entry = QueryPolicy::NodeGetFirstReferrer(node);
while (entry) {
_SendEntryNotification(entry, notify);
entry = QueryPolicy::NodeGetNextReferrer(node, entry);
}
}
}
template<typename QueryPolicy>
void
Query<QueryPolicy>::LiveUpdateRenameMove(Entry* entry, Node* node,
ino_t oldDirectoryID, const char* oldName, size_t oldLength,
ino_t newDirectoryID, const char* newName, size_t newLength)
{
if (fPort < 0 || fExpression == NULL)
return;
// TODO: check if the attribute is part of the query at all...
status_t oldStatus = fExpression->Root()->Match(entry, node, "name",
B_STRING_TYPE, (const uint8*)oldName, oldLength);
status_t newStatus = fExpression->Root()->Match(entry, node, "name",
B_STRING_TYPE, (const uint8*)newName, newLength);
if (oldStatus != MATCH_OK || oldStatus != newStatus)
return;
// The entry stays in the query, notify query listeners about the rename
// or move
// We send a notification for the given entry, if any, or otherwise for
// all entries referring to the node;
if (entry != NULL) {
_SendEntryNotification(entry, notify_query_entry_removed);
_SendEntryNotification(entry, notify_query_entry_created);
} else {
entry = QueryPolicy::NodeGetFirstReferrer(node);
while (entry) {
_SendEntryNotification(entry, notify_query_entry_removed);
_SendEntryNotification(entry, notify_query_entry_created);
entry = QueryPolicy::NodeGetNextReferrer(node, entry);
}
}
}
template<typename QueryPolicy>
status_t
Query<QueryPolicy>::_GetNextEntry(struct dirent* dirent, size_t size)
{
// If we don't have an equation to use yet/anymore, get a new one
// from the stack
while (true) {
if (fIterator == NULL) {
if (!fStack.Pop(&fCurrent)
|| fCurrent == NULL)
return B_ENTRY_NOT_FOUND;
status_t status = fCurrent->PrepareQuery(fContext, fIndex,
&fIterator, fFlags & B_QUERY_NON_INDEXED);
if (status == B_ENTRY_NOT_FOUND) {
// try next equation
continue;
}
if (status != B_OK)
return status;
}
if (fCurrent == NULL)
QUERY_RETURN_ERROR(B_ERROR);
status_t status = fCurrent->GetNextMatching(fContext, fIterator, dirent,
size);
if (status != B_OK) {
QueryPolicy::IndexIteratorDelete(fIterator);
fIterator = NULL;
fCurrent = NULL;
} else {
// only return if we have another entry
return B_OK;
}
}
}
template<typename QueryPolicy>
void
Query<QueryPolicy>::_SendEntryNotification(Entry* entry,
status_t (*notify)(port_id, int32, dev_t, ino_t, const char*, ino_t))
{
char nameBuffer[QueryPolicy::kMaxFileNameLength];
const char* name = QueryPolicy::EntryGetNameNoCopy(entry, nameBuffer,
sizeof(nameBuffer));
if (name != NULL) {
notify(fPort, fToken, QueryPolicy::ContextGetVolumeID(fContext),
QueryPolicy::EntryGetParentID(entry), name,
QueryPolicy::EntryGetNodeID(entry));
}
}
} // namespace QueryParser
#endif // _FILE_SYSTEMS_QUERY_PARSER_H