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fts5_index.c
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8357 lines (7546 loc) · 257 KB
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/*
** 2014 May 31
**
** The author disclaims copyright to this source code. In place of
** a legal notice, here is a blessing:
**
** May you do good and not evil.
** May you find forgiveness for yourself and forgive others.
** May you share freely, never taking more than you give.
**
******************************************************************************
**
** Low level access to the FTS index stored in the database file. The
** routines in this file file implement all read and write access to the
** %_data table. Other parts of the system access this functionality via
** the interface defined in fts5Int.h.
*/
#include "fts5Int.h"
/*
** Overview:
**
** The %_data table contains all the FTS indexes for an FTS5 virtual table.
** As well as the main term index, there may be up to 31 prefix indexes.
** The format is similar to FTS3/4, except that:
**
** * all segment b-tree leaf data is stored in fixed size page records
** (e.g. 1000 bytes). A single doclist may span multiple pages. Care is
** taken to ensure it is possible to iterate in either direction through
** the entries in a doclist, or to seek to a specific entry within a
** doclist, without loading it into memory.
**
** * large doclists that span many pages have associated "doclist index"
** records that contain a copy of the first rowid on each page spanned by
** the doclist. This is used to speed up seek operations, and merges of
** large doclists with very small doclists.
**
** * extra fields in the "structure record" record the state of ongoing
** incremental merge operations.
**
*/
#define FTS5_OPT_WORK_UNIT 1000 /* Number of leaf pages per optimize step */
#define FTS5_WORK_UNIT 64 /* Number of leaf pages in unit of work */
#define FTS5_MIN_DLIDX_SIZE 4 /* Add dlidx if this many empty pages */
#define FTS5_MAIN_PREFIX '0'
#if FTS5_MAX_PREFIX_INDEXES > 31
# error "FTS5_MAX_PREFIX_INDEXES is too large"
#endif
#define FTS5_MAX_LEVEL 64
/*
** There are two versions of the format used for the structure record:
**
** 1. the legacy format, that may be read by all fts5 versions, and
**
** 2. the V2 format, which is used by contentless_delete=1 databases.
**
** Both begin with a 4-byte "configuration cookie" value. Then, a legacy
** format structure record contains a varint - the number of levels in
** the structure. Whereas a V2 structure record contains the constant
** 4 bytes [0xff 0x00 0x00 0x01]. This is unambiguous as the value of a
** varint has to be at least 16256 to begin with "0xFF". And the default
** maximum number of levels is 64.
**
** See below for more on structure record formats.
*/
#define FTS5_STRUCTURE_V2 "\xFF\x00\x00\x01"
/*
** Details:
**
** The %_data table managed by this module,
**
** CREATE TABLE %_data(id INTEGER PRIMARY KEY, block BLOB);
**
** , contains the following 6 types of records. See the comments surrounding
** the FTS5_*_ROWID macros below for a description of how %_data rowids are
** assigned to each fo them.
**
** 1. Structure Records:
**
** The set of segments that make up an index - the index structure - are
** recorded in a single record within the %_data table. The record consists
** of a single 32-bit configuration cookie value followed by a list of
** SQLite varints.
**
** If the structure record is a V2 record, the configuration cookie is
** followed by the following 4 bytes: [0xFF 0x00 0x00 0x01].
**
** Next, the record continues with three varints:
**
** + number of levels,
** + total number of segments on all levels,
** + value of write counter.
**
** Then, for each level from 0 to nMax:
**
** + number of input segments in ongoing merge.
** + total number of segments in level.
** + for each segment from oldest to newest:
** + segment id (always > 0)
** + first leaf page number (often 1, always greater than 0)
** + final leaf page number
**
** Then, for V2 structures only:
**
** + lower origin counter value,
** + upper origin counter value,
** + the number of tombstone hash pages.
**
** 2. The Averages Record:
**
** A single record within the %_data table. The data is a list of varints.
** The first value is the number of rows in the index. Then, for each column
** from left to right, the total number of tokens in the column for all
** rows of the table.
**
** 3. Segment leaves:
**
** TERM/DOCLIST FORMAT:
**
** Most of each segment leaf is taken up by term/doclist data. The
** general format of term/doclist, starting with the first term
** on the leaf page, is:
**
** varint : size of first term
** blob: first term data
** doclist: first doclist
** zero-or-more {
** varint: number of bytes in common with previous term
** varint: number of bytes of new term data (nNew)
** blob: nNew bytes of new term data
** doclist: next doclist
** }
**
** doclist format:
**
** varint: first rowid
** poslist: first poslist
** zero-or-more {
** varint: rowid delta (always > 0)
** poslist: next poslist
** }
**
** poslist format:
**
** varint: size of poslist in bytes multiplied by 2, not including
** this field. Plus 1 if this entry carries the "delete" flag.
** collist: collist for column 0
** zero-or-more {
** 0x01 byte
** varint: column number (I)
** collist: collist for column I
** }
**
** collist format:
**
** varint: first offset + 2
** zero-or-more {
** varint: offset delta + 2
** }
**
** PAGE FORMAT
**
** Each leaf page begins with a 4-byte header containing 2 16-bit
** unsigned integer fields in big-endian format. They are:
**
** * The byte offset of the first rowid on the page, if it exists
** and occurs before the first term (otherwise 0).
**
** * The byte offset of the start of the page footer. If the page
** footer is 0 bytes in size, then this field is the same as the
** size of the leaf page in bytes.
**
** The page footer consists of a single varint for each term located
** on the page. Each varint is the byte offset of the current term
** within the page, delta-compressed against the previous value. In
** other words, the first varint in the footer is the byte offset of
** the first term, the second is the byte offset of the second less that
** of the first, and so on.
**
** The term/doclist format described above is accurate if the entire
** term/doclist data fits on a single leaf page. If this is not the case,
** the format is changed in two ways:
**
** + if the first rowid on a page occurs before the first term, it
** is stored as a literal value:
**
** varint: first rowid
**
** + the first term on each page is stored in the same way as the
** very first term of the segment:
**
** varint : size of first term
** blob: first term data
**
** 5. Segment doclist indexes:
**
** Doclist indexes are themselves b-trees, however they usually consist of
** a single leaf record only. The format of each doclist index leaf page
** is:
**
** * Flags byte. Bits are:
** 0x01: Clear if leaf is also the root page, otherwise set.
**
** * Page number of fts index leaf page. As a varint.
**
** * First rowid on page indicated by previous field. As a varint.
**
** * A list of varints, one for each subsequent termless page. A
** positive delta if the termless page contains at least one rowid,
** or an 0x00 byte otherwise.
**
** Internal doclist index nodes are:
**
** * Flags byte. Bits are:
** 0x01: Clear for root page, otherwise set.
**
** * Page number of first child page. As a varint.
**
** * Copy of first rowid on page indicated by previous field. As a varint.
**
** * A list of delta-encoded varints - the first rowid on each subsequent
** child page.
**
** 6. Tombstone Hash Page
**
** These records are only ever present in contentless_delete=1 tables.
** There are zero or more of these associated with each segment. They
** are used to store the tombstone rowids for rows contained in the
** associated segments.
**
** The set of nHashPg tombstone hash pages associated with a single
** segment together form a single hash table containing tombstone rowids.
** To find the page of the hash on which a key might be stored:
**
** iPg = (rowid % nHashPg)
**
** Then, within page iPg, which has nSlot slots:
**
** iSlot = (rowid / nHashPg) % nSlot
**
** Each tombstone hash page begins with an 8 byte header:
**
** 1-byte: Key-size (the size in bytes of each slot). Either 4 or 8.
** 1-byte: rowid-0-tombstone flag. This flag is only valid on the
** first tombstone hash page for each segment (iPg=0). If set,
** the hash table contains rowid 0. If clear, it does not.
** Rowid 0 is handled specially.
** 2-bytes: unused.
** 4-bytes: Big-endian integer containing number of entries on page.
**
** Following this are nSlot 4 or 8 byte slots (depending on the key-size
** in the first byte of the page header). The number of slots may be
** determined based on the size of the page record and the key-size:
**
** nSlot = (nByte - 8) / key-size
*/
/*
** Rowids for the averages and structure records in the %_data table.
*/
#define FTS5_AVERAGES_ROWID 1 /* Rowid used for the averages record */
#define FTS5_STRUCTURE_ROWID 10 /* The structure record */
/*
** Macros determining the rowids used by segment leaves and dlidx leaves
** and nodes. All nodes and leaves are stored in the %_data table with large
** positive rowids.
**
** Each segment has a unique non-zero 16-bit id.
**
** The rowid for each segment leaf is found by passing the segment id and
** the leaf page number to the FTS5_SEGMENT_ROWID macro. Leaves are numbered
** sequentially starting from 1.
*/
#define FTS5_DATA_ID_B 16 /* Max seg id number 65535 */
#define FTS5_DATA_DLI_B 1 /* Doclist-index flag (1 bit) */
#define FTS5_DATA_HEIGHT_B 5 /* Max dlidx tree height of 32 */
#define FTS5_DATA_PAGE_B 31 /* Max page number of 2147483648 */
#define fts5_dri(segid, dlidx, height, pgno) ( \
((i64)(segid) << (FTS5_DATA_PAGE_B+FTS5_DATA_HEIGHT_B+FTS5_DATA_DLI_B)) + \
((i64)(dlidx) << (FTS5_DATA_PAGE_B + FTS5_DATA_HEIGHT_B)) + \
((i64)(height) << (FTS5_DATA_PAGE_B)) + \
((i64)(pgno)) \
)
#define FTS5_SEGMENT_ROWID(segid, pgno) fts5_dri(segid, 0, 0, pgno)
#define FTS5_DLIDX_ROWID(segid, height, pgno) fts5_dri(segid, 1, height, pgno)
#define FTS5_TOMBSTONE_ROWID(segid,ipg) fts5_dri(segid+(1<<16), 0, 0, ipg)
#ifdef SQLITE_DEBUG
int sqlite3Fts5Corrupt() { return SQLITE_CORRUPT_VTAB; }
#endif
/*
** Each time a blob is read from the %_data table, it is padded with this
** many zero bytes. This makes it easier to decode the various record formats
** without overreading if the records are corrupt.
*/
#define FTS5_DATA_ZERO_PADDING 8
#define FTS5_DATA_PADDING 20
typedef struct Fts5Data Fts5Data;
typedef struct Fts5DlidxIter Fts5DlidxIter;
typedef struct Fts5DlidxLvl Fts5DlidxLvl;
typedef struct Fts5DlidxWriter Fts5DlidxWriter;
typedef struct Fts5Iter Fts5Iter;
typedef struct Fts5PageWriter Fts5PageWriter;
typedef struct Fts5SegIter Fts5SegIter;
typedef struct Fts5DoclistIter Fts5DoclistIter;
typedef struct Fts5SegWriter Fts5SegWriter;
typedef struct Fts5Structure Fts5Structure;
typedef struct Fts5StructureLevel Fts5StructureLevel;
typedef struct Fts5StructureSegment Fts5StructureSegment;
struct Fts5Data {
u8 *p; /* Pointer to buffer containing record */
int nn; /* Size of record in bytes */
int szLeaf; /* Size of leaf without page-index */
};
/*
** One object per %_data table.
**
** nContentlessDelete:
** The number of contentless delete operations since the most recent
** call to fts5IndexFlush() or fts5IndexDiscardData(). This is tracked
** so that extra auto-merge work can be done by fts5IndexFlush() to
** account for the delete operations.
*/
struct Fts5Index {
Fts5Config *pConfig; /* Virtual table configuration */
char *zDataTbl; /* Name of %_data table */
int nWorkUnit; /* Leaf pages in a "unit" of work */
/*
** Variables related to the accumulation of tokens and doclists within the
** in-memory hash tables before they are flushed to disk.
*/
Fts5Hash *pHash; /* Hash table for in-memory data */
int nPendingData; /* Current bytes of pending data */
i64 iWriteRowid; /* Rowid for current doc being written */
int bDelete; /* Current write is a delete */
int nContentlessDelete; /* Number of contentless delete ops */
int nPendingRow; /* Number of INSERT in hash table */
/* Error state. */
int rc; /* Current error code */
/* State used by the fts5DataXXX() functions. */
sqlite3_blob *pReader; /* RO incr-blob open on %_data table */
sqlite3_stmt *pWriter; /* "INSERT ... %_data VALUES(?,?)" */
sqlite3_stmt *pDeleter; /* "DELETE FROM %_data ... id>=? AND id<=?" */
sqlite3_stmt *pIdxWriter; /* "INSERT ... %_idx VALUES(?,?,?,?)" */
sqlite3_stmt *pIdxDeleter; /* "DELETE FROM %_idx WHERE segid=?" */
sqlite3_stmt *pIdxSelect;
int nRead; /* Total number of blocks read */
sqlite3_stmt *pDeleteFromIdx;
sqlite3_stmt *pDataVersion;
i64 iStructVersion; /* data_version when pStruct read */
Fts5Structure *pStruct; /* Current db structure (or NULL) */
};
struct Fts5DoclistIter {
u8 *aEof; /* Pointer to 1 byte past end of doclist */
/* Output variables. aPoslist==0 at EOF */
i64 iRowid;
u8 *aPoslist;
int nPoslist;
int nSize;
};
/*
** The contents of the "structure" record for each index are represented
** using an Fts5Structure record in memory. Which uses instances of the
** other Fts5StructureXXX types as components.
**
** nOriginCntr:
** This value is set to non-zero for structure records created for
** contentlessdelete=1 tables only. In that case it represents the
** origin value to apply to the next top-level segment created.
*/
struct Fts5StructureSegment {
int iSegid; /* Segment id */
int pgnoFirst; /* First leaf page number in segment */
int pgnoLast; /* Last leaf page number in segment */
/* contentlessdelete=1 tables only: */
u64 iOrigin1;
u64 iOrigin2;
int nPgTombstone; /* Number of tombstone hash table pages */
u64 nEntryTombstone; /* Number of tombstone entries that "count" */
u64 nEntry; /* Number of rows in this segment */
};
struct Fts5StructureLevel {
int nMerge; /* Number of segments in incr-merge */
int nSeg; /* Total number of segments on level */
Fts5StructureSegment *aSeg; /* Array of segments. aSeg[0] is oldest. */
};
struct Fts5Structure {
int nRef; /* Object reference count */
u64 nWriteCounter; /* Total leaves written to level 0 */
u64 nOriginCntr; /* Origin value for next top-level segment */
int nSegment; /* Total segments in this structure */
int nLevel; /* Number of levels in this index */
Fts5StructureLevel aLevel[1]; /* Array of nLevel level objects */
};
/*
** An object of type Fts5SegWriter is used to write to segments.
*/
struct Fts5PageWriter {
int pgno; /* Page number for this page */
int iPrevPgidx; /* Previous value written into pgidx */
Fts5Buffer buf; /* Buffer containing leaf data */
Fts5Buffer pgidx; /* Buffer containing page-index */
Fts5Buffer term; /* Buffer containing previous term on page */
};
struct Fts5DlidxWriter {
int pgno; /* Page number for this page */
int bPrevValid; /* True if iPrev is valid */
i64 iPrev; /* Previous rowid value written to page */
Fts5Buffer buf; /* Buffer containing page data */
};
struct Fts5SegWriter {
int iSegid; /* Segid to write to */
Fts5PageWriter writer; /* PageWriter object */
i64 iPrevRowid; /* Previous rowid written to current leaf */
u8 bFirstRowidInDoclist; /* True if next rowid is first in doclist */
u8 bFirstRowidInPage; /* True if next rowid is first in page */
/* TODO1: Can use (writer.pgidx.n==0) instead of bFirstTermInPage */
u8 bFirstTermInPage; /* True if next term will be first in leaf */
int nLeafWritten; /* Number of leaf pages written */
int nEmpty; /* Number of contiguous term-less nodes */
int nDlidx; /* Allocated size of aDlidx[] array */
Fts5DlidxWriter *aDlidx; /* Array of Fts5DlidxWriter objects */
/* Values to insert into the %_idx table */
Fts5Buffer btterm; /* Next term to insert into %_idx table */
int iBtPage; /* Page number corresponding to btterm */
};
typedef struct Fts5CResult Fts5CResult;
struct Fts5CResult {
u16 iFirst; /* aSeg[] index of firstest iterator */
u8 bTermEq; /* True if the terms are equal */
};
/*
** Object for iterating through a single segment, visiting each term/rowid
** pair in the segment.
**
** pSeg:
** The segment to iterate through.
**
** iLeafPgno:
** Current leaf page number within segment.
**
** iLeafOffset:
** Byte offset within the current leaf that is the first byte of the
** position list data (one byte passed the position-list size field).
**
** pLeaf:
** Buffer containing current leaf page data. Set to NULL at EOF.
**
** iTermLeafPgno, iTermLeafOffset:
** Leaf page number containing the last term read from the segment. And
** the offset immediately following the term data.
**
** flags:
** Mask of FTS5_SEGITER_XXX values. Interpreted as follows:
**
** FTS5_SEGITER_ONETERM:
** If set, set the iterator to point to EOF after the current doclist
** has been exhausted. Do not proceed to the next term in the segment.
**
** FTS5_SEGITER_REVERSE:
** This flag is only ever set if FTS5_SEGITER_ONETERM is also set. If
** it is set, iterate through rowid in descending order instead of the
** default ascending order.
**
** iRowidOffset/nRowidOffset/aRowidOffset:
** These are used if the FTS5_SEGITER_REVERSE flag is set.
**
** For each rowid on the page corresponding to the current term, the
** corresponding aRowidOffset[] entry is set to the byte offset of the
** start of the "position-list-size" field within the page.
**
** iTermIdx:
** Index of current term on iTermLeafPgno.
**
** apTombstone/nTombstone:
** These are used for contentless_delete=1 tables only. When the cursor
** is first allocated, the apTombstone[] array is allocated so that it
** is large enough for all tombstones hash pages associated with the
** segment. The pages themselves are loaded lazily from the database as
** they are required.
*/
struct Fts5SegIter {
Fts5StructureSegment *pSeg; /* Segment to iterate through */
int flags; /* Mask of configuration flags */
int iLeafPgno; /* Current leaf page number */
Fts5Data *pLeaf; /* Current leaf data */
Fts5Data *pNextLeaf; /* Leaf page (iLeafPgno+1) */
i64 iLeafOffset; /* Byte offset within current leaf */
Fts5Data **apTombstone; /* Array of tombstone pages */
int nTombstone;
/* Next method */
void (*xNext)(Fts5Index*, Fts5SegIter*, int*);
/* The page and offset from which the current term was read. The offset
** is the offset of the first rowid in the current doclist. */
int iTermLeafPgno;
int iTermLeafOffset;
int iPgidxOff; /* Next offset in pgidx */
int iEndofDoclist;
/* The following are only used if the FTS5_SEGITER_REVERSE flag is set. */
int iRowidOffset; /* Current entry in aRowidOffset[] */
int nRowidOffset; /* Allocated size of aRowidOffset[] array */
int *aRowidOffset; /* Array of offset to rowid fields */
Fts5DlidxIter *pDlidx; /* If there is a doclist-index */
/* Variables populated based on current entry. */
Fts5Buffer term; /* Current term */
i64 iRowid; /* Current rowid */
int nPos; /* Number of bytes in current position list */
u8 bDel; /* True if the delete flag is set */
};
/*
** Argument is a pointer to an Fts5Data structure that contains a
** leaf page.
*/
#define ASSERT_SZLEAF_OK(x) assert( \
(x)->szLeaf==(x)->nn || (x)->szLeaf==fts5GetU16(&(x)->p[2]) \
)
#define FTS5_SEGITER_ONETERM 0x01
#define FTS5_SEGITER_REVERSE 0x02
/*
** Argument is a pointer to an Fts5Data structure that contains a leaf
** page. This macro evaluates to true if the leaf contains no terms, or
** false if it contains at least one term.
*/
#define fts5LeafIsTermless(x) ((x)->szLeaf >= (x)->nn)
#define fts5LeafTermOff(x, i) (fts5GetU16(&(x)->p[(x)->szLeaf + (i)*2]))
#define fts5LeafFirstRowidOff(x) (fts5GetU16((x)->p))
/*
** Object for iterating through the merged results of one or more segments,
** visiting each term/rowid pair in the merged data.
**
** nSeg is always a power of two greater than or equal to the number of
** segments that this object is merging data from. Both the aSeg[] and
** aFirst[] arrays are sized at nSeg entries. The aSeg[] array is padded
** with zeroed objects - these are handled as if they were iterators opened
** on empty segments.
**
** The results of comparing segments aSeg[N] and aSeg[N+1], where N is an
** even number, is stored in aFirst[(nSeg+N)/2]. The "result" of the
** comparison in this context is the index of the iterator that currently
** points to the smaller term/rowid combination. Iterators at EOF are
** considered to be greater than all other iterators.
**
** aFirst[1] contains the index in aSeg[] of the iterator that points to
** the smallest key overall. aFirst[0] is unused.
**
** poslist:
** Used by sqlite3Fts5IterPoslist() when the poslist needs to be buffered.
** There is no way to tell if this is populated or not.
*/
struct Fts5Iter {
Fts5IndexIter base; /* Base class containing output vars */
Fts5Index *pIndex; /* Index that owns this iterator */
Fts5Buffer poslist; /* Buffer containing current poslist */
Fts5Colset *pColset; /* Restrict matches to these columns */
/* Invoked to set output variables. */
void (*xSetOutputs)(Fts5Iter*, Fts5SegIter*);
int nSeg; /* Size of aSeg[] array */
int bRev; /* True to iterate in reverse order */
u8 bSkipEmpty; /* True to skip deleted entries */
i64 iSwitchRowid; /* Firstest rowid of other than aFirst[1] */
Fts5CResult *aFirst; /* Current merge state (see above) */
Fts5SegIter aSeg[1]; /* Array of segment iterators */
};
/*
** An instance of the following type is used to iterate through the contents
** of a doclist-index record.
**
** pData:
** Record containing the doclist-index data.
**
** bEof:
** Set to true once iterator has reached EOF.
**
** iOff:
** Set to the current offset within record pData.
*/
struct Fts5DlidxLvl {
Fts5Data *pData; /* Data for current page of this level */
int iOff; /* Current offset into pData */
int bEof; /* At EOF already */
int iFirstOff; /* Used by reverse iterators */
/* Output variables */
int iLeafPgno; /* Page number of current leaf page */
i64 iRowid; /* First rowid on leaf iLeafPgno */
};
struct Fts5DlidxIter {
int nLvl;
int iSegid;
Fts5DlidxLvl aLvl[1];
};
static void fts5PutU16(u8 *aOut, u16 iVal){
aOut[0] = (iVal>>8);
aOut[1] = (iVal&0xFF);
}
static u16 fts5GetU16(const u8 *aIn){
return ((u16)aIn[0] << 8) + aIn[1];
}
/*
** The only argument points to a buffer at least 8 bytes in size. This
** function interprets the first 8 bytes of the buffer as a 64-bit big-endian
** unsigned integer and returns the result.
*/
static u64 fts5GetU64(u8 *a){
return ((u64)a[0] << 56)
+ ((u64)a[1] << 48)
+ ((u64)a[2] << 40)
+ ((u64)a[3] << 32)
+ ((u64)a[4] << 24)
+ ((u64)a[5] << 16)
+ ((u64)a[6] << 8)
+ ((u64)a[7] << 0);
}
/*
** The only argument points to a buffer at least 4 bytes in size. This
** function interprets the first 4 bytes of the buffer as a 32-bit big-endian
** unsigned integer and returns the result.
*/
static u32 fts5GetU32(const u8 *a){
return ((u32)a[0] << 24)
+ ((u32)a[1] << 16)
+ ((u32)a[2] << 8)
+ ((u32)a[3] << 0);
}
/*
** Write iVal, formated as a 64-bit big-endian unsigned integer, to the
** buffer indicated by the first argument.
*/
static void fts5PutU64(u8 *a, u64 iVal){
a[0] = ((iVal >> 56) & 0xFF);
a[1] = ((iVal >> 48) & 0xFF);
a[2] = ((iVal >> 40) & 0xFF);
a[3] = ((iVal >> 32) & 0xFF);
a[4] = ((iVal >> 24) & 0xFF);
a[5] = ((iVal >> 16) & 0xFF);
a[6] = ((iVal >> 8) & 0xFF);
a[7] = ((iVal >> 0) & 0xFF);
}
/*
** Write iVal, formated as a 32-bit big-endian unsigned integer, to the
** buffer indicated by the first argument.
*/
static void fts5PutU32(u8 *a, u32 iVal){
a[0] = ((iVal >> 24) & 0xFF);
a[1] = ((iVal >> 16) & 0xFF);
a[2] = ((iVal >> 8) & 0xFF);
a[3] = ((iVal >> 0) & 0xFF);
}
/*
** Allocate and return a buffer at least nByte bytes in size.
**
** If an OOM error is encountered, return NULL and set the error code in
** the Fts5Index handle passed as the first argument.
*/
static void *fts5IdxMalloc(Fts5Index *p, sqlite3_int64 nByte){
return sqlite3Fts5MallocZero(&p->rc, nByte);
}
/*
** Compare the contents of the pLeft buffer with the pRight/nRight blob.
**
** Return -ve if pLeft is smaller than pRight, 0 if they are equal or
** +ve if pRight is smaller than pLeft. In other words:
**
** res = *pLeft - *pRight
*/
#ifdef SQLITE_DEBUG
static int fts5BufferCompareBlob(
Fts5Buffer *pLeft, /* Left hand side of comparison */
const u8 *pRight, int nRight /* Right hand side of comparison */
){
int nCmp = MIN(pLeft->n, nRight);
int res = memcmp(pLeft->p, pRight, nCmp);
return (res==0 ? (pLeft->n - nRight) : res);
}
#endif
/*
** Compare the contents of the two buffers using memcmp(). If one buffer
** is a prefix of the other, it is considered the lesser.
**
** Return -ve if pLeft is smaller than pRight, 0 if they are equal or
** +ve if pRight is smaller than pLeft. In other words:
**
** res = *pLeft - *pRight
*/
static int fts5BufferCompare(Fts5Buffer *pLeft, Fts5Buffer *pRight){
int nCmp, res;
nCmp = MIN(pLeft->n, pRight->n);
assert( nCmp<=0 || pLeft->p!=0 );
assert( nCmp<=0 || pRight->p!=0 );
res = fts5Memcmp(pLeft->p, pRight->p, nCmp);
return (res==0 ? (pLeft->n - pRight->n) : res);
}
static int fts5LeafFirstTermOff(Fts5Data *pLeaf){
int ret;
fts5GetVarint32(&pLeaf->p[pLeaf->szLeaf], ret);
return ret;
}
/*
** Close the read-only blob handle, if it is open.
*/
void sqlite3Fts5IndexCloseReader(Fts5Index *p){
if( p->pReader ){
sqlite3_blob *pReader = p->pReader;
p->pReader = 0;
sqlite3_blob_close(pReader);
}
}
/*
** Retrieve a record from the %_data table.
**
** If an error occurs, NULL is returned and an error left in the
** Fts5Index object.
*/
static Fts5Data *fts5DataRead(Fts5Index *p, i64 iRowid){
Fts5Data *pRet = 0;
if( p->rc==SQLITE_OK ){
int rc = SQLITE_OK;
if( p->pReader ){
/* This call may return SQLITE_ABORT if there has been a savepoint
** rollback since it was last used. In this case a new blob handle
** is required. */
sqlite3_blob *pBlob = p->pReader;
p->pReader = 0;
rc = sqlite3_blob_reopen(pBlob, iRowid);
assert( p->pReader==0 );
p->pReader = pBlob;
if( rc!=SQLITE_OK ){
sqlite3Fts5IndexCloseReader(p);
}
if( rc==SQLITE_ABORT ) rc = SQLITE_OK;
}
/* If the blob handle is not open at this point, open it and seek
** to the requested entry. */
if( p->pReader==0 && rc==SQLITE_OK ){
Fts5Config *pConfig = p->pConfig;
rc = sqlite3_blob_open(pConfig->db,
pConfig->zDb, p->zDataTbl, "block", iRowid, 0, &p->pReader
);
}
/* If either of the sqlite3_blob_open() or sqlite3_blob_reopen() calls
** above returned SQLITE_ERROR, return SQLITE_CORRUPT_VTAB instead.
** All the reasons those functions might return SQLITE_ERROR - missing
** table, missing row, non-blob/text in block column - indicate
** backing store corruption. */
if( rc==SQLITE_ERROR ) rc = FTS5_CORRUPT;
if( rc==SQLITE_OK ){
u8 *aOut = 0; /* Read blob data into this buffer */
int nByte = sqlite3_blob_bytes(p->pReader);
sqlite3_int64 nAlloc = sizeof(Fts5Data) + nByte + FTS5_DATA_PADDING;
pRet = (Fts5Data*)sqlite3_malloc64(nAlloc);
if( pRet ){
pRet->nn = nByte;
aOut = pRet->p = (u8*)&pRet[1];
}else{
rc = SQLITE_NOMEM;
}
if( rc==SQLITE_OK ){
rc = sqlite3_blob_read(p->pReader, aOut, nByte, 0);
}
if( rc!=SQLITE_OK ){
sqlite3_free(pRet);
pRet = 0;
}else{
/* TODO1: Fix this */
pRet->p[nByte] = 0x00;
pRet->p[nByte+1] = 0x00;
pRet->szLeaf = fts5GetU16(&pRet->p[2]);
}
}
p->rc = rc;
p->nRead++;
}
assert( (pRet==0)==(p->rc!=SQLITE_OK) );
return pRet;
}
/*
** Release a reference to data record returned by an earlier call to
** fts5DataRead().
*/
static void fts5DataRelease(Fts5Data *pData){
sqlite3_free(pData);
}
static Fts5Data *fts5LeafRead(Fts5Index *p, i64 iRowid){
Fts5Data *pRet = fts5DataRead(p, iRowid);
if( pRet ){
if( pRet->nn<4 || pRet->szLeaf>pRet->nn ){
p->rc = FTS5_CORRUPT;
fts5DataRelease(pRet);
pRet = 0;
}
}
return pRet;
}
static int fts5IndexPrepareStmt(
Fts5Index *p,
sqlite3_stmt **ppStmt,
char *zSql
){
if( p->rc==SQLITE_OK ){
if( zSql ){
p->rc = sqlite3_prepare_v3(p->pConfig->db, zSql, -1,
SQLITE_PREPARE_PERSISTENT|SQLITE_PREPARE_NO_VTAB,
ppStmt, 0);
}else{
p->rc = SQLITE_NOMEM;
}
}
sqlite3_free(zSql);
return p->rc;
}
/*
** INSERT OR REPLACE a record into the %_data table.
*/
static void fts5DataWrite(Fts5Index *p, i64 iRowid, const u8 *pData, int nData){
if( p->rc!=SQLITE_OK ) return;
if( p->pWriter==0 ){
Fts5Config *pConfig = p->pConfig;
fts5IndexPrepareStmt(p, &p->pWriter, sqlite3_mprintf(
"REPLACE INTO '%q'.'%q_data'(id, block) VALUES(?,?)",
pConfig->zDb, pConfig->zName
));
if( p->rc ) return;
}
sqlite3_bind_int64(p->pWriter, 1, iRowid);
sqlite3_bind_blob(p->pWriter, 2, pData, nData, SQLITE_STATIC);
sqlite3_step(p->pWriter);
p->rc = sqlite3_reset(p->pWriter);
sqlite3_bind_null(p->pWriter, 2);
}
/*
** Execute the following SQL:
**
** DELETE FROM %_data WHERE id BETWEEN $iFirst AND $iLast
*/
static void fts5DataDelete(Fts5Index *p, i64 iFirst, i64 iLast){
if( p->rc!=SQLITE_OK ) return;
if( p->pDeleter==0 ){
Fts5Config *pConfig = p->pConfig;
char *zSql = sqlite3_mprintf(
"DELETE FROM '%q'.'%q_data' WHERE id>=? AND id<=?",
pConfig->zDb, pConfig->zName
);
if( fts5IndexPrepareStmt(p, &p->pDeleter, zSql) ) return;
}
sqlite3_bind_int64(p->pDeleter, 1, iFirst);
sqlite3_bind_int64(p->pDeleter, 2, iLast);
sqlite3_step(p->pDeleter);
p->rc = sqlite3_reset(p->pDeleter);
}
/*
** Remove all records associated with segment iSegid.
*/
static void fts5DataRemoveSegment(Fts5Index *p, Fts5StructureSegment *pSeg){
int iSegid = pSeg->iSegid;
i64 iFirst = FTS5_SEGMENT_ROWID(iSegid, 0);
i64 iLast = FTS5_SEGMENT_ROWID(iSegid+1, 0)-1;
fts5DataDelete(p, iFirst, iLast);
if( pSeg->nPgTombstone ){
i64 iTomb1 = FTS5_TOMBSTONE_ROWID(iSegid, 0);
i64 iTomb2 = FTS5_TOMBSTONE_ROWID(iSegid, pSeg->nPgTombstone-1);
fts5DataDelete(p, iTomb1, iTomb2);
}
if( p->pIdxDeleter==0 ){
Fts5Config *pConfig = p->pConfig;
fts5IndexPrepareStmt(p, &p->pIdxDeleter, sqlite3_mprintf(
"DELETE FROM '%q'.'%q_idx' WHERE segid=?",
pConfig->zDb, pConfig->zName
));
}
if( p->rc==SQLITE_OK ){
sqlite3_bind_int(p->pIdxDeleter, 1, iSegid);
sqlite3_step(p->pIdxDeleter);
p->rc = sqlite3_reset(p->pIdxDeleter);
}
}
/*
** Release a reference to an Fts5Structure object returned by an earlier
** call to fts5StructureRead() or fts5StructureDecode().
*/
static void fts5StructureRelease(Fts5Structure *pStruct){
if( pStruct && 0>=(--pStruct->nRef) ){
int i;
assert( pStruct->nRef==0 );
for(i=0; i<pStruct->nLevel; i++){
sqlite3_free(pStruct->aLevel[i].aSeg);
}
sqlite3_free(pStruct);
}
}
static void fts5StructureRef(Fts5Structure *pStruct){
pStruct->nRef++;
}
void *sqlite3Fts5StructureRef(Fts5Index *p){
fts5StructureRef(p->pStruct);
return (void*)p->pStruct;
}
void sqlite3Fts5StructureRelease(void *p){
if( p ){
fts5StructureRelease((Fts5Structure*)p);
}
}
int sqlite3Fts5StructureTest(Fts5Index *p, void *pStruct){
if( p->pStruct!=(Fts5Structure*)pStruct ){
return SQLITE_ABORT;
}
return SQLITE_OK;
}
/*
** Ensure that structure object (*pp) is writable.
**
** This function is a no-op if (*pRc) is not SQLITE_OK when it is called. If
** an error occurs, (*pRc) is set to an SQLite error code before returning.
*/
static void fts5StructureMakeWritable(int *pRc, Fts5Structure **pp){
Fts5Structure *p = *pp;