add sqlite original source code

source/libs/tdb/src/sqlite/btmutex.c

+/*
+** 2007 August 27
+**
+** 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.
+**
+*************************************************************************
+**
+** This file contains code used to implement mutexes on Btree objects.
+** This code really belongs in btree.c.  But btree.c is getting too
+** big and we want to break it down some.  This packaged seemed like
+** a good breakout.
+*/
+#include "btreeInt.h"
+#ifndef SQLITE_OMIT_SHARED_CACHE
+#if SQLITE_THREADSAFE
+
+/*
+** Obtain the BtShared mutex associated with B-Tree handle p. Also,
+** set BtShared.db to the database handle associated with p and the
+** p->locked boolean to true.
+*/
+static void lockBtreeMutex(Btree *p){
+  assert( p->locked==0 );
+  assert( sqlite3_mutex_notheld(p->pBt->mutex) );
+  assert( sqlite3_mutex_held(p->db->mutex) );
+
+  sqlite3_mutex_enter(p->pBt->mutex);
+  p->pBt->db = p->db;
+  p->locked = 1;
+}
+
+/*
+** Release the BtShared mutex associated with B-Tree handle p and
+** clear the p->locked boolean.
+*/
+static void SQLITE_NOINLINE unlockBtreeMutex(Btree *p){
+  BtShared *pBt = p->pBt;
+  assert( p->locked==1 );
+  assert( sqlite3_mutex_held(pBt->mutex) );
+  assert( sqlite3_mutex_held(p->db->mutex) );
+  assert( p->db==pBt->db );
+
+  sqlite3_mutex_leave(pBt->mutex);
+  p->locked = 0;
+}
+
+/* Forward reference */
+static void SQLITE_NOINLINE btreeLockCarefully(Btree *p);
+
+/*
+** Enter a mutex on the given BTree object.
+**
+** If the object is not sharable, then no mutex is ever required
+** and this routine is a no-op.  The underlying mutex is non-recursive.
+** But we keep a reference count in Btree.wantToLock so the behavior
+** of this interface is recursive.
+**
+** To avoid deadlocks, multiple Btrees are locked in the same order
+** by all database connections.  The p->pNext is a list of other
+** Btrees belonging to the same database connection as the p Btree
+** which need to be locked after p.  If we cannot get a lock on
+** p, then first unlock all of the others on p->pNext, then wait
+** for the lock to become available on p, then relock all of the
+** subsequent Btrees that desire a lock.
+*/
+void sqlite3BtreeEnter(Btree *p){
+  /* Some basic sanity checking on the Btree.  The list of Btrees
+  ** connected by pNext and pPrev should be in sorted order by
+  ** Btree.pBt value. All elements of the list should belong to
+  ** the same connection. Only shared Btrees are on the list. */
+  assert( p->pNext==0 || p->pNext->pBt>p->pBt );
+  assert( p->pPrev==0 || p->pPrev->pBt<p->pBt );
+  assert( p->pNext==0 || p->pNext->db==p->db );
+  assert( p->pPrev==0 || p->pPrev->db==p->db );
+  assert( p->sharable || (p->pNext==0 && p->pPrev==0) );
+
+  /* Check for locking consistency */
+  assert( !p->locked || p->wantToLock>0 );
+  assert( p->sharable || p->wantToLock==0 );
+
+  /* We should already hold a lock on the database connection */
+  assert( sqlite3_mutex_held(p->db->mutex) );
+
+  /* Unless the database is sharable and unlocked, then BtShared.db
+  ** should already be set correctly. */
+  assert( (p->locked==0 && p->sharable) || p->pBt->db==p->db );
+
+  if( !p->sharable ) return;
+  p->wantToLock++;
+  if( p->locked ) return;
+  btreeLockCarefully(p);
+}
+
+/* This is a helper function for sqlite3BtreeLock(). By moving
+** complex, but seldom used logic, out of sqlite3BtreeLock() and
+** into this routine, we avoid unnecessary stack pointer changes
+** and thus help the sqlite3BtreeLock() routine to run much faster
+** in the common case.
+*/
+static void SQLITE_NOINLINE btreeLockCarefully(Btree *p){
+  Btree *pLater;
+
+  /* In most cases, we should be able to acquire the lock we
+  ** want without having to go through the ascending lock
+  ** procedure that follows.  Just be sure not to block.
+  */
+  if( sqlite3_mutex_try(p->pBt->mutex)==SQLITE_OK ){
+    p->pBt->db = p->db;
+    p->locked = 1;
+    return;
+  }
+
+  /* To avoid deadlock, first release all locks with a larger
+  ** BtShared address.  Then acquire our lock.  Then reacquire
+  ** the other BtShared locks that we used to hold in ascending
+  ** order.
+  */
+  for(pLater=p->pNext; pLater; pLater=pLater->pNext){
+    assert( pLater->sharable );
+    assert( pLater->pNext==0 || pLater->pNext->pBt>pLater->pBt );
+    assert( !pLater->locked || pLater->wantToLock>0 );
+    if( pLater->locked ){
+      unlockBtreeMutex(pLater);
+    }
+  }
+  lockBtreeMutex(p);
+  for(pLater=p->pNext; pLater; pLater=pLater->pNext){
+    if( pLater->wantToLock ){
+      lockBtreeMutex(pLater);
+    }
+  }
+}
+
+
+/*
+** Exit the recursive mutex on a Btree.
+*/
+void sqlite3BtreeLeave(Btree *p){
+  assert( sqlite3_mutex_held(p->db->mutex) );
+  if( p->sharable ){
+    assert( p->wantToLock>0 );
+    p->wantToLock--;
+    if( p->wantToLock==0 ){
+      unlockBtreeMutex(p);
+    }
+  }
+}
+
+#ifndef NDEBUG
+/*
+** Return true if the BtShared mutex is held on the btree, or if the
+** B-Tree is not marked as sharable.
+**
+** This routine is used only from within assert() statements.
+*/
+int sqlite3BtreeHoldsMutex(Btree *p){
+  assert( p->sharable==0 || p->locked==0 || p->wantToLock>0 );
+  assert( p->sharable==0 || p->locked==0 || p->db==p->pBt->db );
+  assert( p->sharable==0 || p->locked==0 || sqlite3_mutex_held(p->pBt->mutex) );
+  assert( p->sharable==0 || p->locked==0 || sqlite3_mutex_held(p->db->mutex) );
+
+  return (p->sharable==0 || p->locked);
+}
+#endif
+
+
+/*
+** Enter the mutex on every Btree associated with a database
+** connection.  This is needed (for example) prior to parsing
+** a statement since we will be comparing table and column names
+** against all schemas and we do not want those schemas being
+** reset out from under us.
+**
+** There is a corresponding leave-all procedures.
+**
+** Enter the mutexes in accending order by BtShared pointer address
+** to avoid the possibility of deadlock when two threads with
+** two or more btrees in common both try to lock all their btrees
+** at the same instant.
+*/
+static void SQLITE_NOINLINE btreeEnterAll(sqlite3 *db){
+  int i;
+  int skipOk = 1;
+  Btree *p;
+  assert( sqlite3_mutex_held(db->mutex) );
+  for(i=0; i<db->nDb; i++){
+    p = db->aDb[i].pBt;
+    if( p && p->sharable ){
+      sqlite3BtreeEnter(p);
+      skipOk = 0;
+    }
+  }
+  db->noSharedCache = skipOk;
+}
+void sqlite3BtreeEnterAll(sqlite3 *db){
+  if( db->noSharedCache==0 ) btreeEnterAll(db);
+}
+static void SQLITE_NOINLINE btreeLeaveAll(sqlite3 *db){
+  int i;
+  Btree *p;
+  assert( sqlite3_mutex_held(db->mutex) );
+  for(i=0; i<db->nDb; i++){
+    p = db->aDb[i].pBt;
+    if( p ) sqlite3BtreeLeave(p);
+  }
+}
+void sqlite3BtreeLeaveAll(sqlite3 *db){
+  if( db->noSharedCache==0 ) btreeLeaveAll(db);
+}
+
+#ifndef NDEBUG
+/*
+** Return true if the current thread holds the database connection
+** mutex and all required BtShared mutexes.
+**
+** This routine is used inside assert() statements only.
+*/
+int sqlite3BtreeHoldsAllMutexes(sqlite3 *db){
+  int i;
+  if( !sqlite3_mutex_held(db->mutex) ){
+    return 0;
+  }
+  for(i=0; i<db->nDb; i++){
+    Btree *p;
+    p = db->aDb[i].pBt;
+    if( p && p->sharable &&
+         (p->wantToLock==0 || !sqlite3_mutex_held(p->pBt->mutex)) ){
+      return 0;
+    }
+  }
+  return 1;
+}
+#endif /* NDEBUG */
+
+#ifndef NDEBUG
+/*
+** Return true if the correct mutexes are held for accessing the
+** db->aDb[iDb].pSchema structure.  The mutexes required for schema
+** access are:
+**
+**   (1) The mutex on db
+**   (2) if iDb!=1, then the mutex on db->aDb[iDb].pBt.
+**
+** If pSchema is not NULL, then iDb is computed from pSchema and
+** db using sqlite3SchemaToIndex().
+*/
+int sqlite3SchemaMutexHeld(sqlite3 *db, int iDb, Schema *pSchema){
+  Btree *p;
+  assert( db!=0 );
+  if( pSchema ) iDb = sqlite3SchemaToIndex(db, pSchema);
+  assert( iDb>=0 && iDb<db->nDb );
+  if( !sqlite3_mutex_held(db->mutex) ) return 0;
+  if( iDb==1 ) return 1;
+  p = db->aDb[iDb].pBt;
+  assert( p!=0 );
+  return p->sharable==0 || p->locked==1;
+}
+#endif /* NDEBUG */
+
+#else /* SQLITE_THREADSAFE>0 above.  SQLITE_THREADSAFE==0 below */
+/*
+** The following are special cases for mutex enter routines for use
+** in single threaded applications that use shared cache.  Except for
+** these two routines, all mutex operations are no-ops in that case and
+** are null #defines in btree.h.
+**
+** If shared cache is disabled, then all btree mutex routines, including
+** the ones below, are no-ops and are null #defines in btree.h.
+*/
+
+void sqlite3BtreeEnter(Btree *p){
+  p->pBt->db = p->db;
+}
+void sqlite3BtreeEnterAll(sqlite3 *db){
+  int i;
+  for(i=0; i<db->nDb; i++){
+    Btree *p = db->aDb[i].pBt;
+    if( p ){
+      p->pBt->db = p->db;
+    }
+  }
+}
+#endif /* if SQLITE_THREADSAFE */
+
+#ifndef SQLITE_OMIT_INCRBLOB
+/*
+** Enter a mutex on a Btree given a cursor owned by that Btree. 
+**
+** These entry points are used by incremental I/O only. Enter() is required 
+** any time OMIT_SHARED_CACHE is not defined, regardless of whether or not 
+** the build is threadsafe. Leave() is only required by threadsafe builds.
+*/
+void sqlite3BtreeEnterCursor(BtCursor *pCur){
+  sqlite3BtreeEnter(pCur->pBtree);
+}
+# if SQLITE_THREADSAFE
+void sqlite3BtreeLeaveCursor(BtCursor *pCur){
+  sqlite3BtreeLeave(pCur->pBtree);
+}
+# endif
+#endif /* ifndef SQLITE_OMIT_INCRBLOB */
+
+#endif /* ifndef SQLITE_OMIT_SHARED_CACHE */

source/libs/tdb/src/sqliteinc/btree.h

+/*
+** 2001 September 15
+**
+** 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.
+**
+*************************************************************************
+** This header file defines the interface that the sqlite B-Tree file
+** subsystem.  See comments in the source code for a detailed description
+** of what each interface routine does.
+*/
+#ifndef SQLITE_BTREE_H
+#define SQLITE_BTREE_H
+
+/* TODO: This definition is just included so other modules compile. It
+** needs to be revisited.
+*/
+#define SQLITE_N_BTREE_META 16
+
+/*
+** If defined as non-zero, auto-vacuum is enabled by default. Otherwise
+** it must be turned on for each database using "PRAGMA auto_vacuum = 1".
+*/
+#ifndef SQLITE_DEFAULT_AUTOVACUUM
+  #define SQLITE_DEFAULT_AUTOVACUUM 0
+#endif
+
+#define BTREE_AUTOVACUUM_NONE 0        /* Do not do auto-vacuum */
+#define BTREE_AUTOVACUUM_FULL 1        /* Do full auto-vacuum */
+#define BTREE_AUTOVACUUM_INCR 2        /* Incremental vacuum */
+
+/*
+** Forward declarations of structure
+*/
+typedef struct Btree Btree;
+typedef struct BtCursor BtCursor;
+typedef struct BtShared BtShared;
+typedef struct BtreePayload BtreePayload;
+
+
+int sqlite3BtreeOpen(
+  sqlite3_vfs *pVfs,       /* VFS to use with this b-tree */
+  const char *zFilename,   /* Name of database file to open */
+  sqlite3 *db,             /* Associated database connection */
+  Btree **ppBtree,         /* Return open Btree* here */
+  int flags,               /* Flags */
+  int vfsFlags             /* Flags passed through to VFS open */
+);
+
+/* The flags parameter to sqlite3BtreeOpen can be the bitwise or of the
+** following values.
+**
+** NOTE:  These values must match the corresponding PAGER_ values in
+** pager.h.
+*/
+#define BTREE_OMIT_JOURNAL  1  /* Do not create or use a rollback journal */
+#define BTREE_MEMORY        2  /* This is an in-memory DB */
+#define BTREE_SINGLE        4  /* The file contains at most 1 b-tree */
+#define BTREE_UNORDERED     8  /* Use of a hash implementation is OK */
+
+int sqlite3BtreeClose(Btree*);
+int sqlite3BtreeSetCacheSize(Btree*,int);
+int sqlite3BtreeSetSpillSize(Btree*,int);
+#if SQLITE_MAX_MMAP_SIZE>0
+  int sqlite3BtreeSetMmapLimit(Btree*,sqlite3_int64);
+#endif
+int sqlite3BtreeSetPagerFlags(Btree*,unsigned);
+int sqlite3BtreeSetPageSize(Btree *p, int nPagesize, int nReserve, int eFix);
+int sqlite3BtreeGetPageSize(Btree*);
+Pgno sqlite3BtreeMaxPageCount(Btree*,Pgno);
+Pgno sqlite3BtreeLastPage(Btree*);
+int sqlite3BtreeSecureDelete(Btree*,int);
+int sqlite3BtreeGetRequestedReserve(Btree*);
+int sqlite3BtreeGetReserveNoMutex(Btree *p);
+int sqlite3BtreeSetAutoVacuum(Btree *, int);
+int sqlite3BtreeGetAutoVacuum(Btree *);
+int sqlite3BtreeBeginTrans(Btree*,int,int*);
+int sqlite3BtreeCommitPhaseOne(Btree*, const char*);
+int sqlite3BtreeCommitPhaseTwo(Btree*, int);
+int sqlite3BtreeCommit(Btree*);
+int sqlite3BtreeRollback(Btree*,int,int);
+int sqlite3BtreeBeginStmt(Btree*,int);
+int sqlite3BtreeCreateTable(Btree*, Pgno*, int flags);
+int sqlite3BtreeTxnState(Btree*);
+int sqlite3BtreeIsInBackup(Btree*);
+
+void *sqlite3BtreeSchema(Btree *, int, void(*)(void *));
+int sqlite3BtreeSchemaLocked(Btree *pBtree);
+#ifndef SQLITE_OMIT_SHARED_CACHE
+int sqlite3BtreeLockTable(Btree *pBtree, int iTab, u8 isWriteLock);
+#endif
+
+/* Savepoints are named, nestable SQL transactions mostly implemented */ 
+/* in vdbe.c and pager.c See https://sqlite.org/lang_savepoint.html */
+int sqlite3BtreeSavepoint(Btree *, int, int);
+
+/* "Checkpoint" only refers to WAL. See https://sqlite.org/wal.html#ckpt */
+#ifndef SQLITE_OMIT_WAL
+  int sqlite3BtreeCheckpoint(Btree*, int, int *, int *);  
+#endif
+
+const char *sqlite3BtreeGetFilename(Btree *);
+const char *sqlite3BtreeGetJournalname(Btree *);
+int sqlite3BtreeCopyFile(Btree *, Btree *);
+
+int sqlite3BtreeIncrVacuum(Btree *);
+
+/* The flags parameter to sqlite3BtreeCreateTable can be the bitwise OR
+** of the flags shown below.
+**
+** Every SQLite table must have either BTREE_INTKEY or BTREE_BLOBKEY set.
+** With BTREE_INTKEY, the table key is a 64-bit integer and arbitrary data
+** is stored in the leaves.  (BTREE_INTKEY is used for SQL tables.)  With
+** BTREE_BLOBKEY, the key is an arbitrary BLOB and no content is stored
+** anywhere - the key is the content.  (BTREE_BLOBKEY is used for SQL
+** indices.)
+*/
+#define BTREE_INTKEY     1    /* Table has only 64-bit signed integer keys */
+#define BTREE_BLOBKEY    2    /* Table has keys only - no data */
+
+int sqlite3BtreeDropTable(Btree*, int, int*);
+int sqlite3BtreeClearTable(Btree*, int, i64*);
+int sqlite3BtreeClearTableOfCursor(BtCursor*);
+int sqlite3BtreeTripAllCursors(Btree*, int, int);
+
+void sqlite3BtreeGetMeta(Btree *pBtree, int idx, u32 *pValue);
+int sqlite3BtreeUpdateMeta(Btree*, int idx, u32 value);
+
+int sqlite3BtreeNewDb(Btree *p);
+
+/*
+** The second parameter to sqlite3BtreeGetMeta or sqlite3BtreeUpdateMeta
+** should be one of the following values. The integer values are assigned 
+** to constants so that the offset of the corresponding field in an
+** SQLite database header may be found using the following formula:
+**
+**   offset = 36 + (idx * 4)
+**
+** For example, the free-page-count field is located at byte offset 36 of
+** the database file header. The incr-vacuum-flag field is located at
+** byte offset 64 (== 36+4*7).
+**
+** The BTREE_DATA_VERSION value is not really a value stored in the header.
+** It is a read-only number computed by the pager.  But we merge it with
+** the header value access routines since its access pattern is the same.
+** Call it a "virtual meta value".
+*/
+#define BTREE_FREE_PAGE_COUNT     0
+#define BTREE_SCHEMA_VERSION      1
+#define BTREE_FILE_FORMAT         2
+#define BTREE_DEFAULT_CACHE_SIZE  3
+#define BTREE_LARGEST_ROOT_PAGE   4
+#define BTREE_TEXT_ENCODING       5
+#define BTREE_USER_VERSION        6
+#define BTREE_INCR_VACUUM         7
+#define BTREE_APPLICATION_ID      8
+#define BTREE_DATA_VERSION        15  /* A virtual meta-value */
+
+/*
+** Kinds of hints that can be passed into the sqlite3BtreeCursorHint()
+** interface.
+**
+** BTREE_HINT_RANGE  (arguments: Expr*, Mem*)
+**
+**     The first argument is an Expr* (which is guaranteed to be constant for
+**     the lifetime of the cursor) that defines constraints on which rows
+**     might be fetched with this cursor.  The Expr* tree may contain
+**     TK_REGISTER nodes that refer to values stored in the array of registers
+**     passed as the second parameter.  In other words, if Expr.op==TK_REGISTER
+**     then the value of the node is the value in Mem[pExpr.iTable].  Any
+**     TK_COLUMN node in the expression tree refers to the Expr.iColumn-th
+**     column of the b-tree of the cursor.  The Expr tree will not contain
+**     any function calls nor subqueries nor references to b-trees other than
+**     the cursor being hinted.
+**
+**     The design of the _RANGE hint is aid b-tree implementations that try
+**     to prefetch content from remote machines - to provide those
+**     implementations with limits on what needs to be prefetched and thereby
+**     reduce network bandwidth.
+**
+** Note that BTREE_HINT_FLAGS with BTREE_BULKLOAD is the only hint used by
+** standard SQLite.  The other hints are provided for extentions that use
+** the SQLite parser and code generator but substitute their own storage
+** engine.
+*/
+#define BTREE_HINT_RANGE 0       /* Range constraints on queries */
+
+/*
+** Values that may be OR'd together to form the argument to the
+** BTREE_HINT_FLAGS hint for sqlite3BtreeCursorHint():
+**
+** The BTREE_BULKLOAD flag is set on index cursors when the index is going
+** to be filled with content that is already in sorted order.
+**
+** The BTREE_SEEK_EQ flag is set on cursors that will get OP_SeekGE or
+** OP_SeekLE opcodes for a range search, but where the range of entries
+** selected will all have the same key.  In other words, the cursor will
+** be used only for equality key searches.
+**
+*/
+#define BTREE_BULKLOAD 0x00000001  /* Used to full index in sorted order */
+#define BTREE_SEEK_EQ  0x00000002  /* EQ seeks only - no range seeks */
+
+/* 
+** Flags passed as the third argument to sqlite3BtreeCursor().
+**
+** For read-only cursors the wrFlag argument is always zero. For read-write
+** cursors it may be set to either (BTREE_WRCSR|BTREE_FORDELETE) or just
+** (BTREE_WRCSR). If the BTREE_FORDELETE bit is set, then the cursor will
+** only be used by SQLite for the following:
+**
+**   * to seek to and then delete specific entries, and/or
+**
+**   * to read values that will be used to create keys that other
+**     BTREE_FORDELETE cursors will seek to and delete.
+**
+** The BTREE_FORDELETE flag is an optimization hint.  It is not used by
+** by this, the native b-tree engine of SQLite, but it is available to
+** alternative storage engines that might be substituted in place of this
+** b-tree system.  For alternative storage engines in which a delete of
+** the main table row automatically deletes corresponding index rows,
+** the FORDELETE flag hint allows those alternative storage engines to
+** skip a lot of work.  Namely:  FORDELETE cursors may treat all SEEK
+** and DELETE operations as no-ops, and any READ operation against a
+** FORDELETE cursor may return a null row: 0x01 0x00.
+*/
+#define BTREE_WRCSR     0x00000004     /* read-write cursor */
+#define BTREE_FORDELETE 0x00000008     /* Cursor is for seek/delete only */
+
+int sqlite3BtreeCursor(
+  Btree*,                              /* BTree containing table to open */
+  Pgno iTable,                         /* Index of root page */
+  int wrFlag,                          /* 1 for writing.  0 for read-only */
+  struct KeyInfo*,                     /* First argument to compare function */
+  BtCursor *pCursor                    /* Space to write cursor structure */
+);
+BtCursor *sqlite3BtreeFakeValidCursor(void);
+int sqlite3BtreeCursorSize(void);
+void sqlite3BtreeCursorZero(BtCursor*);
+void sqlite3BtreeCursorHintFlags(BtCursor*, unsigned);
+#ifdef SQLITE_ENABLE_CURSOR_HINTS
+void sqlite3BtreeCursorHint(BtCursor*, int, ...);
+#endif
+
+int sqlite3BtreeCloseCursor(BtCursor*);
+int sqlite3BtreeTableMoveto(
+  BtCursor*,
+  i64 intKey,
+  int bias,
+  int *pRes
+);
+int sqlite3BtreeIndexMoveto(
+  BtCursor*,
+  UnpackedRecord *pUnKey,
+  int *pRes
+);
+int sqlite3BtreeCursorHasMoved(BtCursor*);
+int sqlite3BtreeCursorRestore(BtCursor*, int*);
+int sqlite3BtreeDelete(BtCursor*, u8 flags);
+
+/* Allowed flags for sqlite3BtreeDelete() and sqlite3BtreeInsert() */
+#define BTREE_SAVEPOSITION 0x02  /* Leave cursor pointing at NEXT or PREV */
+#define BTREE_AUXDELETE    0x04  /* not the primary delete operation */
+#define BTREE_APPEND       0x08  /* Insert is likely an append */
+#define BTREE_PREFORMAT    0x80  /* Inserted data is a preformated cell */
+
+/* An instance of the BtreePayload object describes the content of a single
+** entry in either an index or table btree.
+**
+** Index btrees (used for indexes and also WITHOUT ROWID tables) contain
+** an arbitrary key and no data.  These btrees have pKey,nKey set to the
+** key and the pData,nData,nZero fields are uninitialized.  The aMem,nMem
+** fields give an array of Mem objects that are a decomposition of the key.
+** The nMem field might be zero, indicating that no decomposition is available.
+**
+** Table btrees (used for rowid tables) contain an integer rowid used as
+** the key and passed in the nKey field.  The pKey field is zero.  
+** pData,nData hold the content of the new entry.  nZero extra zero bytes
+** are appended to the end of the content when constructing the entry.
+** The aMem,nMem fields are uninitialized for table btrees.
+**
+** Field usage summary:
+**
+**               Table BTrees                   Index Btrees
+**
+**   pKey        always NULL                    encoded key
+**   nKey        the ROWID                      length of pKey
+**   pData       data                           not used
+**   aMem        not used                       decomposed key value
+**   nMem        not used                       entries in aMem
+**   nData       length of pData                not used
+**   nZero       extra zeros after pData        not used
+**
+** This object is used to pass information into sqlite3BtreeInsert().  The
+** same information used to be passed as five separate parameters.  But placing
+** the information into this object helps to keep the interface more 
+** organized and understandable, and it also helps the resulting code to
+** run a little faster by using fewer registers for parameter passing.
+*/
+struct BtreePayload {
+  const void *pKey;       /* Key content for indexes.  NULL for tables */
+  sqlite3_int64 nKey;     /* Size of pKey for indexes.  PRIMARY KEY for tabs */
+  const void *pData;      /* Data for tables. */
+  sqlite3_value *aMem;    /* First of nMem value in the unpacked pKey */
+  u16 nMem;               /* Number of aMem[] value.  Might be zero */
+  int nData;              /* Size of pData.  0 if none. */
+  int nZero;              /* Extra zero data appended after pData,nData */
+};
+
+int sqlite3BtreeInsert(BtCursor*, const BtreePayload *pPayload,
+                       int flags, int seekResult);
+int sqlite3BtreeFirst(BtCursor*, int *pRes);
+int sqlite3BtreeLast(BtCursor*, int *pRes);
+int sqlite3BtreeNext(BtCursor*, int flags);
+int sqlite3BtreeEof(BtCursor*);
+int sqlite3BtreePrevious(BtCursor*, int flags);
+i64 sqlite3BtreeIntegerKey(BtCursor*);
+void sqlite3BtreeCursorPin(BtCursor*);
+void sqlite3BtreeCursorUnpin(BtCursor*);
+#ifdef SQLITE_ENABLE_OFFSET_SQL_FUNC
+i64 sqlite3BtreeOffset(BtCursor*);
+#endif
+int sqlite3BtreePayload(BtCursor*, u32 offset, u32 amt, void*);
+const void *sqlite3BtreePayloadFetch(BtCursor*, u32 *pAmt);
+u32 sqlite3BtreePayloadSize(BtCursor*);
+sqlite3_int64 sqlite3BtreeMaxRecordSize(BtCursor*);
+
+char *sqlite3BtreeIntegrityCheck(sqlite3*,Btree*,Pgno*aRoot,int nRoot,int,int*);
+struct Pager *sqlite3BtreePager(Btree*);
+i64 sqlite3BtreeRowCountEst(BtCursor*);
+
+#ifndef SQLITE_OMIT_INCRBLOB
+int sqlite3BtreePayloadChecked(BtCursor*, u32 offset, u32 amt, void*);
+int sqlite3BtreePutData(BtCursor*, u32 offset, u32 amt, void*);
+void sqlite3BtreeIncrblobCursor(BtCursor *);
+#endif
+void sqlite3BtreeClearCursor(BtCursor *);
+int sqlite3BtreeSetVersion(Btree *pBt, int iVersion);
+int sqlite3BtreeCursorHasHint(BtCursor*, unsigned int mask);
+int sqlite3BtreeIsReadonly(Btree *pBt);
+int sqlite3HeaderSizeBtree(void);
+
+#ifdef SQLITE_DEBUG
+sqlite3_uint64 sqlite3BtreeSeekCount(Btree*);
+#else
+# define sqlite3BtreeSeekCount(X) 0
+#endif
+
+#ifndef NDEBUG
+int sqlite3BtreeCursorIsValid(BtCursor*);
+#endif
+int sqlite3BtreeCursorIsValidNN(BtCursor*);
+
+int sqlite3BtreeCount(sqlite3*, BtCursor*, i64*);
+
+#ifdef SQLITE_TEST
+int sqlite3BtreeCursorInfo(BtCursor*, int*, int);
+void sqlite3BtreeCursorList(Btree*);
+#endif
+
+#ifndef SQLITE_OMIT_WAL
+  int sqlite3BtreeCheckpoint(Btree*, int, int *, int *);
+#endif
+
+int sqlite3BtreeTransferRow(BtCursor*, BtCursor*, i64);
+
+/*
+** If we are not using shared cache, then there is no need to
+** use mutexes to access the BtShared structures.  So make the
+** Enter and Leave procedures no-ops.
+*/
+#ifndef SQLITE_OMIT_SHARED_CACHE
+  void sqlite3BtreeEnter(Btree*);
+  void sqlite3BtreeEnterAll(sqlite3*);
+  int sqlite3BtreeSharable(Btree*);
+  void sqlite3BtreeEnterCursor(BtCursor*);
+  int sqlite3BtreeConnectionCount(Btree*);
+#else
+# define sqlite3BtreeEnter(X) 
+# define sqlite3BtreeEnterAll(X)
+# define sqlite3BtreeSharable(X) 0
+# define sqlite3BtreeEnterCursor(X)
+# define sqlite3BtreeConnectionCount(X) 1
+#endif
+
+#if !defined(SQLITE_OMIT_SHARED_CACHE) && SQLITE_THREADSAFE
+  void sqlite3BtreeLeave(Btree*);
+  void sqlite3BtreeLeaveCursor(BtCursor*);
+  void sqlite3BtreeLeaveAll(sqlite3*);
+#ifndef NDEBUG
+  /* These routines are used inside assert() statements only. */
+  int sqlite3BtreeHoldsMutex(Btree*);
+  int sqlite3BtreeHoldsAllMutexes(sqlite3*);
+  int sqlite3SchemaMutexHeld(sqlite3*,int,Schema*);
+#endif
+#else
+
+# define sqlite3BtreeLeave(X)
+# define sqlite3BtreeLeaveCursor(X)
+# define sqlite3BtreeLeaveAll(X)
+
+# define sqlite3BtreeHoldsMutex(X) 1
+# define sqlite3BtreeHoldsAllMutexes(X) 1
+# define sqlite3SchemaMutexHeld(X,Y,Z) 1
+#endif
+
+
+#endif /* SQLITE_BTREE_H */

source/libs/tdb/src/sqliteinc/pager.h

+/*
+** 2001 September 15
+**
+** 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.
+**
+*************************************************************************
+** This header file defines the interface that the sqlite page cache
+** subsystem.  The page cache subsystem reads and writes a file a page
+** at a time and provides a journal for rollback.
+*/
+
+#ifndef SQLITE_PAGER_H
+#define SQLITE_PAGER_H
+
+/*
+** Default maximum size for persistent journal files. A negative 
+** value means no limit. This value may be overridden using the 
+** sqlite3PagerJournalSizeLimit() API. See also "PRAGMA journal_size_limit".
+*/
+#ifndef SQLITE_DEFAULT_JOURNAL_SIZE_LIMIT
+  #define SQLITE_DEFAULT_JOURNAL_SIZE_LIMIT -1
+#endif
+
+/*
+** The type used to represent a page number.  The first page in a file
+** is called page 1.  0 is used to represent "not a page".
+*/
+typedef u32 Pgno;
+
+/*
+** Each open file is managed by a separate instance of the "Pager" structure.
+*/
+typedef struct Pager Pager;
+
+/*
+** Handle type for pages.
+*/
+typedef struct PgHdr DbPage;
+
+/*
+** Page number PAGER_MJ_PGNO is never used in an SQLite database (it is
+** reserved for working around a windows/posix incompatibility). It is
+** used in the journal to signify that the remainder of the journal file 
+** is devoted to storing a super-journal name - there are no more pages to
+** roll back. See comments for function writeSuperJournal() in pager.c 
+** for details.
+*/
+#define PAGER_MJ_PGNO(x) ((Pgno)((PENDING_BYTE/((x)->pageSize))+1))
+
+/*
+** Allowed values for the flags parameter to sqlite3PagerOpen().
+**
+** NOTE: These values must match the corresponding BTREE_ values in btree.h.
+*/
+#define PAGER_OMIT_JOURNAL  0x0001    /* Do not use a rollback journal */
+#define PAGER_MEMORY        0x0002    /* In-memory database */
+
+/*
+** Valid values for the second argument to sqlite3PagerLockingMode().
+*/
+#define PAGER_LOCKINGMODE_QUERY      -1
+#define PAGER_LOCKINGMODE_NORMAL      0
+#define PAGER_LOCKINGMODE_EXCLUSIVE   1
+
+/*
+** Numeric constants that encode the journalmode.
+**
+** The numeric values encoded here (other than PAGER_JOURNALMODE_QUERY)
+** are exposed in the API via the "PRAGMA journal_mode" command and
+** therefore cannot be changed without a compatibility break.
+*/
+#define PAGER_JOURNALMODE_QUERY     (-1)  /* Query the value of journalmode */
+#define PAGER_JOURNALMODE_DELETE      0   /* Commit by deleting journal file */
+#define PAGER_JOURNALMODE_PERSIST     1   /* Commit by zeroing journal header */
+#define PAGER_JOURNALMODE_OFF         2   /* Journal omitted.  */
+#define PAGER_JOURNALMODE_TRUNCATE    3   /* Commit by truncating journal */
+#define PAGER_JOURNALMODE_MEMORY      4   /* In-memory journal file */
+#define PAGER_JOURNALMODE_WAL         5   /* Use write-ahead logging */
+
+/*
+** Flags that make up the mask passed to sqlite3PagerGet().
+*/
+#define PAGER_GET_NOCONTENT     0x01  /* Do not load data from disk */
+#define PAGER_GET_READONLY      0x02  /* Read-only page is acceptable */
+
+/*
+** Flags for sqlite3PagerSetFlags()
+**
+** Value constraints (enforced via assert()):
+**    PAGER_FULLFSYNC      == SQLITE_FullFSync
+**    PAGER_CKPT_FULLFSYNC == SQLITE_CkptFullFSync
+**    PAGER_CACHE_SPILL    == SQLITE_CacheSpill
+*/
+#define PAGER_SYNCHRONOUS_OFF       0x01  /* PRAGMA synchronous=OFF */
+#define PAGER_SYNCHRONOUS_NORMAL    0x02  /* PRAGMA synchronous=NORMAL */
+#define PAGER_SYNCHRONOUS_FULL      0x03  /* PRAGMA synchronous=FULL */
+#define PAGER_SYNCHRONOUS_EXTRA     0x04  /* PRAGMA synchronous=EXTRA */
+#define PAGER_SYNCHRONOUS_MASK      0x07  /* Mask for four values above */
+#define PAGER_FULLFSYNC             0x08  /* PRAGMA fullfsync=ON */
+#define PAGER_CKPT_FULLFSYNC        0x10  /* PRAGMA checkpoint_fullfsync=ON */
+#define PAGER_CACHESPILL            0x20  /* PRAGMA cache_spill=ON */
+#define PAGER_FLAGS_MASK            0x38  /* All above except SYNCHRONOUS */
+
+/*
+** The remainder of this file contains the declarations of the functions
+** that make up the Pager sub-system API. See source code comments for 
+** a detailed description of each routine.
+*/
+
+/* Open and close a Pager connection. */ 
+int sqlite3PagerOpen(
+  sqlite3_vfs*,
+  Pager **ppPager,
+  const char*,
+  int,
+  int,
+  int,
+  void(*)(DbPage*)
+);
+int sqlite3PagerClose(Pager *pPager, sqlite3*);
+int sqlite3PagerReadFileheader(Pager*, int, unsigned char*);
+
+/* Functions used to configure a Pager object. */
+void sqlite3PagerSetBusyHandler(Pager*, int(*)(void *), void *);
+int sqlite3PagerSetPagesize(Pager*, u32*, int);
+Pgno sqlite3PagerMaxPageCount(Pager*, Pgno);
+void sqlite3PagerSetCachesize(Pager*, int);
+int sqlite3PagerSetSpillsize(Pager*, int);
+void sqlite3PagerSetMmapLimit(Pager *, sqlite3_int64);
+void sqlite3PagerShrink(Pager*);
+void sqlite3PagerSetFlags(Pager*,unsigned);
+int sqlite3PagerLockingMode(Pager *, int);
+int sqlite3PagerSetJournalMode(Pager *, int);
+int sqlite3PagerGetJournalMode(Pager*);
+int sqlite3PagerOkToChangeJournalMode(Pager*);
+i64 sqlite3PagerJournalSizeLimit(Pager *, i64);
+sqlite3_backup **sqlite3PagerBackupPtr(Pager*);
+int sqlite3PagerFlush(Pager*);
+
+/* Functions used to obtain and release page references. */ 
+int sqlite3PagerGet(Pager *pPager, Pgno pgno, DbPage **ppPage, int clrFlag);
+DbPage *sqlite3PagerLookup(Pager *pPager, Pgno pgno);
+void sqlite3PagerRef(DbPage*);
+void sqlite3PagerUnref(DbPage*);
+void sqlite3PagerUnrefNotNull(DbPage*);
+void sqlite3PagerUnrefPageOne(DbPage*);
+
+/* Operations on page references. */
+int sqlite3PagerWrite(DbPage*);
+void sqlite3PagerDontWrite(DbPage*);
+int sqlite3PagerMovepage(Pager*,DbPage*,Pgno,int);
+int sqlite3PagerPageRefcount(DbPage*);
+void *sqlite3PagerGetData(DbPage *); 
+void *sqlite3PagerGetExtra(DbPage *); 
+
+/* Functions used to manage pager transactions and savepoints. */
+void sqlite3PagerPagecount(Pager*, int*);
+int sqlite3PagerBegin(Pager*, int exFlag, int);
+int sqlite3PagerCommitPhaseOne(Pager*,const char *zSuper, int);
+int sqlite3PagerExclusiveLock(Pager*);
+int sqlite3PagerSync(Pager *pPager, const char *zSuper);
+int sqlite3PagerCommitPhaseTwo(Pager*);
+int sqlite3PagerRollback(Pager*);
+int sqlite3PagerOpenSavepoint(Pager *pPager, int n);
+int sqlite3PagerSavepoint(Pager *pPager, int op, int iSavepoint);
+int sqlite3PagerSharedLock(Pager *pPager);
+
+#ifndef SQLITE_OMIT_WAL
+  int sqlite3PagerCheckpoint(Pager *pPager, sqlite3*, int, int*, int*);
+  int sqlite3PagerWalSupported(Pager *pPager);
+  int sqlite3PagerWalCallback(Pager *pPager);
+  int sqlite3PagerOpenWal(Pager *pPager, int *pisOpen);
+  int sqlite3PagerCloseWal(Pager *pPager, sqlite3*);
+# ifdef SQLITE_ENABLE_SNAPSHOT
+  int sqlite3PagerSnapshotGet(Pager*, sqlite3_snapshot **ppSnapshot);
+  int sqlite3PagerSnapshotOpen(Pager*, sqlite3_snapshot *pSnapshot);
+  int sqlite3PagerSnapshotRecover(Pager *pPager);
+  int sqlite3PagerSnapshotCheck(Pager *pPager, sqlite3_snapshot *pSnapshot);
+  void sqlite3PagerSnapshotUnlock(Pager *pPager);
+# endif
+#endif
+
+#if !defined(SQLITE_OMIT_WAL) && defined(SQLITE_ENABLE_SETLK_TIMEOUT)
+  int sqlite3PagerWalWriteLock(Pager*, int);
+  void sqlite3PagerWalDb(Pager*, sqlite3*);
+#else
+# define sqlite3PagerWalWriteLock(y,z) SQLITE_OK
+# define sqlite3PagerWalDb(x,y)
+#endif
+
+#ifdef SQLITE_DIRECT_OVERFLOW_READ
+  int sqlite3PagerDirectReadOk(Pager *pPager, Pgno pgno);
+#endif
+
+#ifdef SQLITE_ENABLE_ZIPVFS
+  int sqlite3PagerWalFramesize(Pager *pPager);
+#endif
+
+/* Functions used to query pager state and configuration. */
+u8 sqlite3PagerIsreadonly(Pager*);
+u32 sqlite3PagerDataVersion(Pager*);
+#ifdef SQLITE_DEBUG
+  int sqlite3PagerRefcount(Pager*);
+#endif
+int sqlite3PagerMemUsed(Pager*);
+const char *sqlite3PagerFilename(const Pager*, int);
+sqlite3_vfs *sqlite3PagerVfs(Pager*);
+sqlite3_file *sqlite3PagerFile(Pager*);
+sqlite3_file *sqlite3PagerJrnlFile(Pager*);
+const char *sqlite3PagerJournalname(Pager*);
+void *sqlite3PagerTempSpace(Pager*);
+int sqlite3PagerIsMemdb(Pager*);
+void sqlite3PagerCacheStat(Pager *, int, int, int *);
+void sqlite3PagerClearCache(Pager*);
+int sqlite3SectorSize(sqlite3_file *);
+
+/* Functions used to truncate the database file. */
+void sqlite3PagerTruncateImage(Pager*,Pgno);
+
+void sqlite3PagerRekey(DbPage*, Pgno, u16);
+
+/* Functions to support testing and debugging. */
+#if !defined(NDEBUG) || defined(SQLITE_TEST)
+  Pgno sqlite3PagerPagenumber(DbPage*);
+  int sqlite3PagerIswriteable(DbPage*);
+#endif
+#ifdef SQLITE_TEST
+  int *sqlite3PagerStats(Pager*);
+  void sqlite3PagerRefdump(Pager*);
+  void disable_simulated_io_errors(void);
+  void enable_simulated_io_errors(void);
+#else
+# define disable_simulated_io_errors()
+# define enable_simulated_io_errors()
+#endif
+
+#endif /* SQLITE_PAGER_H */

source/libs/tdb/src/sqliteinc/pcache.h

+/*
+** 2008 August 05
+**
+** 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.
+**
+*************************************************************************
+** This header file defines the interface that the sqlite page cache
+** subsystem. 
+*/
+
+#ifndef _PCACHE_H_
+
+typedef struct PgHdr PgHdr;
+typedef struct PCache PCache;
+
+/*
+** Every page in the cache is controlled by an instance of the following
+** structure.
+*/
+struct PgHdr {
+  sqlite3_pcache_page *pPage;    /* Pcache object page handle */
+  void *pData;                   /* Page data */
+  void *pExtra;                  /* Extra content */
+  PCache *pCache;                /* PRIVATE: Cache that owns this page */
+  PgHdr *pDirty;                 /* Transient list of dirty sorted by pgno */
+  Pager *pPager;                 /* The pager this page is part of */
+  Pgno pgno;                     /* Page number for this page */
+#ifdef SQLITE_CHECK_PAGES
+  u32 pageHash;                  /* Hash of page content */
+#endif
+  u16 flags;                     /* PGHDR flags defined below */
+
+  /**********************************************************************
+  ** Elements above, except pCache, are public.  All that follow are 
+  ** private to pcache.c and should not be accessed by other modules.
+  ** pCache is grouped with the public elements for efficiency.
+  */
+  i16 nRef;                      /* Number of users of this page */
+  PgHdr *pDirtyNext;             /* Next element in list of dirty pages */
+  PgHdr *pDirtyPrev;             /* Previous element in list of dirty pages */
+                          /* NB: pDirtyNext and pDirtyPrev are undefined if the
+                          ** PgHdr object is not dirty */
+};
+
+/* Bit values for PgHdr.flags */
+#define PGHDR_CLEAN           0x001  /* Page not on the PCache.pDirty list */
+#define PGHDR_DIRTY           0x002  /* Page is on the PCache.pDirty list */
+#define PGHDR_WRITEABLE       0x004  /* Journaled and ready to modify */
+#define PGHDR_NEED_SYNC       0x008  /* Fsync the rollback journal before
+                                     ** writing this page to the database */
+#define PGHDR_DONT_WRITE      0x010  /* Do not write content to disk */
+#define PGHDR_MMAP            0x020  /* This is an mmap page object */
+
+#define PGHDR_WAL_APPEND      0x040  /* Appended to wal file */
+
+/* Initialize and shutdown the page cache subsystem */
+int sqlite3PcacheInitialize(void);
+void sqlite3PcacheShutdown(void);
+
+/* Page cache buffer management:
+** These routines implement SQLITE_CONFIG_PAGECACHE.
+*/
+void sqlite3PCacheBufferSetup(void *, int sz, int n);
+
+/* Create a new pager cache.
+** Under memory stress, invoke xStress to try to make pages clean.
+** Only clean and unpinned pages can be reclaimed.
+*/
+int sqlite3PcacheOpen(
+  int szPage,                    /* Size of every page */
+  int szExtra,                   /* Extra space associated with each page */
+  int bPurgeable,                /* True if pages are on backing store */
+  int (*xStress)(void*, PgHdr*), /* Call to try to make pages clean */
+  void *pStress,                 /* Argument to xStress */
+  PCache *pToInit                /* Preallocated space for the PCache */
+);
+
+/* Modify the page-size after the cache has been created. */
+int sqlite3PcacheSetPageSize(PCache *, int);
+
+/* Return the size in bytes of a PCache object.  Used to preallocate
+** storage space.
+*/
+int sqlite3PcacheSize(void);
+
+/* One release per successful fetch.  Page is pinned until released.
+** Reference counted. 
+*/
+sqlite3_pcache_page *sqlite3PcacheFetch(PCache*, Pgno, int createFlag);
+int sqlite3PcacheFetchStress(PCache*, Pgno, sqlite3_pcache_page**);
+PgHdr *sqlite3PcacheFetchFinish(PCache*, Pgno, sqlite3_pcache_page *pPage);
+void sqlite3PcacheRelease(PgHdr*);
+
+void sqlite3PcacheDrop(PgHdr*);         /* Remove page from cache */
+void sqlite3PcacheMakeDirty(PgHdr*);    /* Make sure page is marked dirty */
+void sqlite3PcacheMakeClean(PgHdr*);    /* Mark a single page as clean */
+void sqlite3PcacheCleanAll(PCache*);    /* Mark all dirty list pages as clean */
+void sqlite3PcacheClearWritable(PCache*);
+
+/* Change a page number.  Used by incr-vacuum. */
+void sqlite3PcacheMove(PgHdr*, Pgno);
+
+/* Remove all pages with pgno>x.  Reset the cache if x==0 */
+void sqlite3PcacheTruncate(PCache*, Pgno x);
+
+/* Get a list of all dirty pages in the cache, sorted by page number */
+PgHdr *sqlite3PcacheDirtyList(PCache*);
+
+/* Reset and close the cache object */
+void sqlite3PcacheClose(PCache*);
+
+/* Clear flags from pages of the page cache */
+void sqlite3PcacheClearSyncFlags(PCache *);
+
+/* Discard the contents of the cache */
+void sqlite3PcacheClear(PCache*);
+
+/* Return the total number of outstanding page references */
+int sqlite3PcacheRefCount(PCache*);
+
+/* Increment the reference count of an existing page */
+void sqlite3PcacheRef(PgHdr*);
+
+int sqlite3PcachePageRefcount(PgHdr*);
+
+/* Return the total number of pages stored in the cache */
+int sqlite3PcachePagecount(PCache*);
+
+#if defined(SQLITE_CHECK_PAGES) || defined(SQLITE_DEBUG)
+/* Iterate through all dirty pages currently stored in the cache. This
+** interface is only available if SQLITE_CHECK_PAGES is defined when the 
+** library is built.
+*/
+void sqlite3PcacheIterateDirty(PCache *pCache, void (*xIter)(PgHdr *));
+#endif
+
+#if defined(SQLITE_DEBUG)
+/* Check invariants on a PgHdr object */
+int sqlite3PcachePageSanity(PgHdr*);
+#endif
+
+/* Set and get the suggested cache-size for the specified pager-cache.
+**
+** If no global maximum is configured, then the system attempts to limit
+** the total number of pages cached by purgeable pager-caches to the sum
+** of the suggested cache-sizes.
+*/
+void sqlite3PcacheSetCachesize(PCache *, int);
+#ifdef SQLITE_TEST
+int sqlite3PcacheGetCachesize(PCache *);
+#endif
+
+/* Set or get the suggested spill-size for the specified pager-cache.
+**
+** The spill-size is the minimum number of pages in cache before the cache
+** will attempt to spill dirty pages by calling xStress.
+*/
+int sqlite3PcacheSetSpillsize(PCache *, int);
+
+/* Free up as much memory as possible from the page cache */
+void sqlite3PcacheShrink(PCache*);
+
+#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
+/* Try to return memory used by the pcache module to the main memory heap */
+int sqlite3PcacheReleaseMemory(int);
+#endif
+
+#ifdef SQLITE_TEST
+void sqlite3PcacheStats(int*,int*,int*,int*);
+#endif
+
+void sqlite3PCacheSetDefault(void);
+
+/* Return the header size */
+int sqlite3HeaderSizePcache(void);
+int sqlite3HeaderSizePcache1(void);
+
+/* Number of dirty pages as a percentage of the configured cache size */
+int sqlite3PCachePercentDirty(PCache*);
+
+#ifdef SQLITE_DIRECT_OVERFLOW_READ
+int sqlite3PCacheIsDirty(PCache *pCache);
+#endif
+
+#endif /* _PCACHE_H_ */

source/libs/tdb/src/sqliteinc/wal.h

+/*
+** 2010 February 1
+**
+** 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.
+**
+*************************************************************************
+** This header file defines the interface to the write-ahead logging 
+** system. Refer to the comments below and the header comment attached to 
+** the implementation of each function in log.c for further details.
+*/
+
+#ifndef SQLITE_WAL_H
+#define SQLITE_WAL_H
+
+#include "sqliteInt.h"
+
+/* Macros for extracting appropriate sync flags for either transaction
+** commits (WAL_SYNC_FLAGS(X)) or for checkpoint ops (CKPT_SYNC_FLAGS(X)):
+*/
+#define WAL_SYNC_FLAGS(X)   ((X)&0x03)
+#define CKPT_SYNC_FLAGS(X)  (((X)>>2)&0x03)
+
+#ifdef SQLITE_OMIT_WAL
+# define sqlite3WalOpen(x,y,z)                   0
+# define sqlite3WalLimit(x,y)
+# define sqlite3WalClose(v,w,x,y,z)              0
+# define sqlite3WalBeginReadTransaction(y,z)     0
+# define sqlite3WalEndReadTransaction(z)
+# define sqlite3WalDbsize(y)                     0
+# define sqlite3WalBeginWriteTransaction(y)      0
+# define sqlite3WalEndWriteTransaction(x)        0
+# define sqlite3WalUndo(x,y,z)                   0
+# define sqlite3WalSavepoint(y,z)
+# define sqlite3WalSavepointUndo(y,z)            0
+# define sqlite3WalFrames(u,v,w,x,y,z)           0
+# define sqlite3WalCheckpoint(q,r,s,t,u,v,w,x,y,z) 0
+# define sqlite3WalCallback(z)                   0
+# define sqlite3WalExclusiveMode(y,z)            0
+# define sqlite3WalHeapMemory(z)                 0
+# define sqlite3WalFramesize(z)                  0
+# define sqlite3WalFindFrame(x,y,z)              0
+# define sqlite3WalFile(x)                       0
+#else
+
+#define WAL_SAVEPOINT_NDATA 4
+
+/* Connection to a write-ahead log (WAL) file. 
+** There is one object of this type for each pager. 
+*/
+typedef struct Wal Wal;
+
+/* Open and close a connection to a write-ahead log. */
+int sqlite3WalOpen(sqlite3_vfs*, sqlite3_file*, const char *, int, i64, Wal**);
+int sqlite3WalClose(Wal *pWal, sqlite3*, int sync_flags, int, u8 *);
+
+/* Set the limiting size of a WAL file. */
+void sqlite3WalLimit(Wal*, i64);
+
+/* Used by readers to open (lock) and close (unlock) a snapshot.  A 
+** snapshot is like a read-transaction.  It is the state of the database
+** at an instant in time.  sqlite3WalOpenSnapshot gets a read lock and
+** preserves the current state even if the other threads or processes
+** write to or checkpoint the WAL.  sqlite3WalCloseSnapshot() closes the
+** transaction and releases the lock.
+*/
+int sqlite3WalBeginReadTransaction(Wal *pWal, int *);
+void sqlite3WalEndReadTransaction(Wal *pWal);
+
+/* Read a page from the write-ahead log, if it is present. */
+int sqlite3WalFindFrame(Wal *, Pgno, u32 *);
+int sqlite3WalReadFrame(Wal *, u32, int, u8 *);
+
+/* If the WAL is not empty, return the size of the database. */
+Pgno sqlite3WalDbsize(Wal *pWal);
+
+/* Obtain or release the WRITER lock. */
+int sqlite3WalBeginWriteTransaction(Wal *pWal);
+int sqlite3WalEndWriteTransaction(Wal *pWal);
+
+/* Undo any frames written (but not committed) to the log */
+int sqlite3WalUndo(Wal *pWal, int (*xUndo)(void *, Pgno), void *pUndoCtx);
+
+/* Return an integer that records the current (uncommitted) write
+** position in the WAL */
+void sqlite3WalSavepoint(Wal *pWal, u32 *aWalData);
+
+/* Move the write position of the WAL back to iFrame.  Called in
+** response to a ROLLBACK TO command. */
+int sqlite3WalSavepointUndo(Wal *pWal, u32 *aWalData);
+
+/* Write a frame or frames to the log. */
+int sqlite3WalFrames(Wal *pWal, int, PgHdr *, Pgno, int, int);
+
+/* Copy pages from the log to the database file */ 
+int sqlite3WalCheckpoint(
+  Wal *pWal,                      /* Write-ahead log connection */
+  sqlite3 *db,                    /* Check this handle's interrupt flag */
+  int eMode,                      /* One of PASSIVE, FULL and RESTART */
+  int (*xBusy)(void*),            /* Function to call when busy */
+  void *pBusyArg,                 /* Context argument for xBusyHandler */
+  int sync_flags,                 /* Flags to sync db file with (or 0) */
+  int nBuf,                       /* Size of buffer nBuf */
+  u8 *zBuf,                       /* Temporary buffer to use */
+  int *pnLog,                     /* OUT: Number of frames in WAL */
+  int *pnCkpt                     /* OUT: Number of backfilled frames in WAL */
+);
+
+/* Return the value to pass to a sqlite3_wal_hook callback, the
+** number of frames in the WAL at the point of the last commit since
+** sqlite3WalCallback() was called.  If no commits have occurred since
+** the last call, then return 0.
+*/
+int sqlite3WalCallback(Wal *pWal);
+
+/* Tell the wal layer that an EXCLUSIVE lock has been obtained (or released)
+** by the pager layer on the database file.
+*/
+int sqlite3WalExclusiveMode(Wal *pWal, int op);
+
+/* Return true if the argument is non-NULL and the WAL module is using
+** heap-memory for the wal-index. Otherwise, if the argument is NULL or the
+** WAL module is using shared-memory, return false. 
+*/
+int sqlite3WalHeapMemory(Wal *pWal);
+
+#ifdef SQLITE_ENABLE_SNAPSHOT
+int sqlite3WalSnapshotGet(Wal *pWal, sqlite3_snapshot **ppSnapshot);
+void sqlite3WalSnapshotOpen(Wal *pWal, sqlite3_snapshot *pSnapshot);
+int sqlite3WalSnapshotRecover(Wal *pWal);
+int sqlite3WalSnapshotCheck(Wal *pWal, sqlite3_snapshot *pSnapshot);
+void sqlite3WalSnapshotUnlock(Wal *pWal);
+#endif
+
+#ifdef SQLITE_ENABLE_ZIPVFS
+/* If the WAL file is not empty, return the number of bytes of content
+** stored in each frame (i.e. the db page-size when the WAL was created).
+*/
+int sqlite3WalFramesize(Wal *pWal);
+#endif
+
+/* Return the sqlite3_file object for the WAL file */
+sqlite3_file *sqlite3WalFile(Wal *pWal);
+
+#ifdef SQLITE_ENABLE_SETLK_TIMEOUT
+int sqlite3WalWriteLock(Wal *pWal, int bLock);
+void sqlite3WalDb(Wal *pWal, sqlite3 *db);
+#endif
+
+#endif /* ifndef SQLITE_OMIT_WAL */
+#endif /* SQLITE_WAL_H */