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+/*
+** 2003 April 6
+**
+** 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 the VACUUM command.
+**
+** Most of the code in this file may be omitted by defining the
+** SQLITE_OMIT_VACUUM macro.
+**
+** $Id$
+*/
+#include "sqliteInt.h"
+#include "os.h"
+
+/*
+** A structure for holding a dynamic string - a string that can grow
+** without bound.
+*/
+typedef struct dynStr dynStr;
+struct dynStr {
+ char *z; /* Text of the string in space obtained from sqliteMalloc() */
+ int nAlloc; /* Amount of space allocated to z[] */
+ int nUsed; /* Next unused slot in z[] */
+};
+
+/*
+** A structure that holds the vacuum context
+*/
+typedef struct vacuumStruct vacuumStruct;
+struct vacuumStruct {
+ sqlite *dbOld; /* Original database */
+ sqlite *dbNew; /* New database */
+ Parse *pParse; /* The parser context */
+ const char *zTable; /* Name of a table being copied */
+ const char *zPragma; /* Pragma to execute with results */
+ dynStr s1, s2; /* Two dynamic strings */
+};
+
+#if !defined(SQLITE_OMIT_VACUUM) || SQLITE_OMIT_VACUUM
+/*
+** Append text to a dynamic string
+*/
+static void appendText(dynStr *p, const char *zText, int nText){
+ if( nText<0 ) nText = strlen(zText);
+ if( p->z==0 || p->nUsed + nText + 1 >= p->nAlloc ){
+ char *zNew;
+ p->nAlloc = p->nUsed + nText + 1000;
+ zNew = sqliteRealloc(p->z, p->nAlloc);
+ if( zNew==0 ){
+ sqliteFree(p->z);
+ memset(p, 0, sizeof(*p));
+ return;
+ }
+ p->z = zNew;
+ }
+ memcpy(&p->z[p->nUsed], zText, nText+1);
+ p->nUsed += nText;
+}
+
+/*
+** Append text to a dynamic string, having first put the text in quotes.
+*/
+static void appendQuoted(dynStr *p, const char *zText){
+ int i, j;
+ appendText(p, "'", 1);
+ for(i=j=0; zText[i]; i++){
+ if( zText[i]=='\'' ){
+ appendText(p, &zText[j], i-j+1);
+ j = i + 1;
+ appendText(p, "'", 1);
+ }
+ }
+ if( j<i ){
+ appendText(p, &zText[j], i-j);
+ }
+ appendText(p, "'", 1);
+}
+
+/*
+** Execute statements of SQL. If an error occurs, write the error
+** message into pParse->zErrMsg and return non-zero.
+*/
+static int execsql(Parse *pParse, sqlite *db, const char *zSql){
+ int rc;
+ char *zErrMsg = 0;
+
+ /* printf("***** executing *****\n%s\n", zSql); */
+ rc = sqlite_exec(db, zSql, 0, 0, &zErrMsg);
+ if( rc ){
+ sqliteErrorMsg(pParse, "%s", zErrMsg);
+ sqlite_freemem(zErrMsg);
+ }
+ return rc;
+}
+
+/*
+** This is the second stage callback. Each invocation contains all the
+** data for a single row of a single table in the original database. This
+** routine must write that information into the new database.
+*/
+static int vacuumCallback2(void *pArg, int argc, char **argv, char **NotUsed){
+ vacuumStruct *p = (vacuumStruct*)pArg;
+ int rc = 0;
+ const char *zSep = "(";
+ int i;
+
+ p->s2.nUsed = 0;
+ appendText(&p->s2, "INSERT INTO ", -1);
+ appendQuoted(&p->s2, p->zTable);
+ appendText(&p->s2, " VALUES", -1);
+ for(i=0; i<argc; i++){
+ appendText(&p->s2, zSep, 1);
+ zSep = ",";
+ if( argv[i]==0 ){
+ appendText(&p->s2, "NULL", 4);
+ }else{
+ appendQuoted(&p->s2, argv[i]);
+ }
+ }
+ appendText(&p->s2,")", 1);
+ rc = execsql(p->pParse, p->dbNew, p->s2.z);
+ return rc;
+}
+
+/*
+** This is the first stage callback. Each invocation contains three
+** arguments where are taken from the SQLITE_MASTER table of the original
+** database: (1) the entry type, (2) the entry name, and (3) the SQL for
+** the entry. In all cases, execute the SQL of the third argument.
+** For tables, run a query to select all entries in that table and
+** transfer them to the second-stage callback.
+*/
+static int vacuumCallback1(void *pArg, int argc, char **argv, char **NotUsed){
+ vacuumStruct *p = (vacuumStruct*)pArg;
+ int rc = 0;
+ assert( argc==3 );
+ assert( argv[0]!=0 );
+ assert( argv[1]!=0 );
+ assert( argv[2]!=0 );
+ rc = execsql(p->pParse, p->dbNew, argv[2]);
+ if( rc==SQLITE_OK && strcmp(argv[0],"table")==0 ){
+ char *zErrMsg = 0;
+ p->s1.nUsed = 0;
+ appendText(&p->s1, "SELECT * FROM ", -1);
+ appendQuoted(&p->s1, argv[1]);
+ p->zTable = argv[1];
+ rc = sqlite_exec(p->dbOld, p->s1.z, vacuumCallback2, p, &zErrMsg);
+ if( rc && p->pParse->zErrMsg==0 ){
+ sqliteErrorMsg(p->pParse, "%s", zErrMsg);
+ }
+ }
+ return rc;
+}
+
+/*
+** This callback is used to transfer PRAGMA settings from one database
+** to the other. The value in argv[0] should be passed to a pragma
+** identified by ((vacuumStruct*)pArg)->zPragma.
+*/
+static int vacuumCallback3(void *pArg, int argc, char **argv, char **NotUsed){
+ vacuumStruct *p = (vacuumStruct*)pArg;
+ int rc = 0;
+ char zBuf[200];
+ assert( argc==1 );
+ assert( argv[0]!=0 );
+ assert( strlen(p->zPragma)<100 );
+ assert( strlen(argv[0])<30 );
+ sprintf(zBuf,"PRAGMA %s=%s;", p->zPragma, argv[0]);
+ rc = execsql(p->pParse, p->dbNew, zBuf);
+ return rc;
+}
+
+/*
+** Generate a random name of 20 character in length.
+*/
+static void randomName(char *zBuf){
+ static const char zChars[] =
+ "abcdefghijklmnopqrstuvwxyz"
+ "0123456789";
+ int i;
+ for(i=0; i<20; i++){
+ int n = sqliteRandomByte() % (sizeof(zChars)-1);
+ zBuf[i] = zChars[n];
+ }
+}
+#endif
+
+/*
+** The non-standard VACUUM command is used to clean up the database,
+** collapse free space, etc. It is modelled after the VACUUM command
+** in PostgreSQL.
+**
+** In version 1.0.x of SQLite, the VACUUM command would call
+** gdbm_reorganize() on all the database tables. But beginning
+** with 2.0.0, SQLite no longer uses GDBM so this command has
+** become a no-op.
+*/
+void sqliteVacuum(Parse *pParse, Token *pTableName){
+#if !defined(SQLITE_OMIT_VACUUM) || SQLITE_OMIT_VACUUM
+ const char *zFilename; /* full pathname of the database file */
+ int nFilename; /* number of characters in zFilename[] */
+ char *zTemp = 0; /* a temporary file in same directory as zFilename */
+ sqlite *dbNew = 0; /* The new vacuumed database */
+ sqlite *db; /* The original database */
+ int rc = SQLITE_OK; /* Return code from service routines */
+ int i; /* Loop counter */
+ char *zErrMsg = 0; /* Error messages stored here */
+ int safety = 0; /* TRUE if safety is off */
+ vacuumStruct sVac; /* Information passed to callbacks */
+
+ /* These are all of the pragmas that need to be transferred over
+ ** to the new database */
+ static const char *zPragma[] = {
+ "default_synchronous",
+ "default_cache_size",
+ /* "default_temp_store", */
+ };
+
+ /* Initial error checks
+ */
+ if( pParse->explain ){
+ return;
+ }
+ db = pParse->db;
+ if( db->flags & SQLITE_InTrans ){
+ sqliteErrorMsg(pParse, "cannot VACUUM from within a transaction");
+ return;
+ }
+ memset(&sVac, 0, sizeof(sVac));
+
+ /* Get the full pathname of the database file and create two
+ ** temporary filenames in the same directory as the original file.
+ */
+ zFilename = sqliteBtreeGetFilename(db->aDb[0].pBt);
+ if( zFilename==0 ){
+ /* This only happens with the in-memory database. VACUUM is a no-op
+ ** there, so just return */
+ return;
+ }
+ nFilename = strlen(zFilename);
+ zTemp = sqliteMalloc( nFilename+100 );
+ if( zTemp==0 ) return;
+ strcpy(zTemp, zFilename);
+ for(i=0; i<10; i++){
+ zTemp[nFilename] = '-';
+ randomName(&zTemp[nFilename+1]);
+ if( !sqliteOsFileExists(zTemp) ) break;
+ }
+ if( i>=10 ){
+ sqliteErrorMsg(pParse, "unable to create a temporary database file "
+ "in the same directory as the original database");
+ goto end_of_vacuum;
+ }
+
+
+ dbNew = sqlite_open(zTemp, 0, &zErrMsg);
+ if( dbNew==0 ){
+ sqliteErrorMsg(pParse, "unable to open a temporary database at %s - %s",
+ zTemp, zErrMsg);
+ goto end_of_vacuum;
+ }
+ if( sqliteSafetyOff(db) ){
+ sqliteErrorMsg(pParse, "library routines called out of sequence");
+ goto end_of_vacuum;
+ }
+ safety = 1;
+ if( execsql(pParse, db, "BEGIN") ) goto end_of_vacuum;
+ if( execsql(pParse, dbNew, "PRAGMA synchronous=off; BEGIN") ){
+ goto end_of_vacuum;
+ }
+ sVac.dbOld = db;
+ sVac.dbNew = dbNew;
+ sVac.pParse = pParse;
+ for(i=0; rc==SQLITE_OK && i<sizeof(zPragma)/sizeof(zPragma[0]); i++){
+ char zBuf[200];
+ assert( strlen(zPragma[i])<100 );
+ sprintf(zBuf, "PRAGMA %s;", zPragma[i]);
+ sVac.zPragma = zPragma[i];
+ rc = sqlite_exec(db, zBuf, vacuumCallback3, &sVac, &zErrMsg);
+ }
+ if( !rc ){
+ rc = sqlite_exec(db, "SELECT type, name, sql FROM sqlite_master "
+ "WHERE sql NOT NULL", vacuumCallback1, &sVac, &zErrMsg);
+ }
+ if( !rc ){
+ rc = sqliteBtreeCopyFile(db->aDb[0].pBt, dbNew->aDb[0].pBt);
+ sqlite_exec(db, "COMMIT", 0, 0, 0);
+ sqlite_exec(db, "ROLLBACK", 0, 0, 0); /* In case the COMMIT failed */
+ sqliteResetInternalSchema(db, 0);
+ }
+
+end_of_vacuum:
+ if( rc && pParse->zErrMsg==0 && zErrMsg!=0 ){
+ sqliteErrorMsg(pParse, "unable to vacuum database - %s", zErrMsg);
+ }
+ if( safety ) {
+ sqlite_exec(db, "COMMIT", 0, 0, 0);
+ sqlite_exec(db, "ROLLBACK", 0, 0, 0); /* In case the COMMIT failed */
+ sqliteSafetyOn(db);
+ }
+ if( dbNew ) sqlite_close(dbNew);
+ sqliteOsDelete(zTemp);
+ sqliteFree(zTemp);
+ sqliteFree(sVac.s1.z);
+ sqliteFree(sVac.s2.z);
+ if( zErrMsg ) sqlite_freemem(zErrMsg);
+ return;
+#endif
+}
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