Initial commit

Signed-off-by: Mavridis Philippe <mavridisf@gmail.com>

1 files changed, 310 insertions, 0 deletions

diff --git a/src/sqlite/vacuum.c b/src/sqlite/vacuum.c
new file mode 100644
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+++ b/src/sqlite/vacuum.c
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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: vacuum.c,v 1.1.1.1 2006/02/03 20:35:17 hoganrobert Exp $
+*/
+#include "sqliteInt.h"
+#include "os.h"
+
+#ifndef SQLITE_OMIT_VACUUM
+/*
+** Generate a random name of 20 character in length.
+*/
+static void randomName(unsigned char *zBuf){
+  static const unsigned char zChars[] =
+    "abcdefghijklmnopqrstuvwxyz"
+    "0123456789";
+  int i;
+  sqlite3Randomness(20, zBuf);
+  for(i=0; i<20; i++){
+    zBuf[i] = zChars[ zBuf[i]%(sizeof(zChars)-1) ];
+  }
+}
+
+/*
+** Execute zSql on database db. Return an error code.
+*/
+static int execSql(sqlite3 *db, const char *zSql){
+  sqlite3_stmt *pStmt;
+  if( SQLITE_OK!=sqlite3_prepare(db, zSql, -1, &pStmt, 0) ){
+    return sqlite3_errcode(db);
+  }
+  while( SQLITE_ROW==sqlite3_step(pStmt) );
+  return sqlite3_finalize(pStmt);
+}
+
+/*
+** Execute zSql on database db. The statement returns exactly
+** one column. Execute this as SQL on the same database.
+*/
+static int execExecSql(sqlite3 *db, const char *zSql){
+  sqlite3_stmt *pStmt;
+  int rc;
+
+  rc = sqlite3_prepare(db, zSql, -1, &pStmt, 0);
+  if( rc!=SQLITE_OK ) return rc;
+
+  while( SQLITE_ROW==sqlite3_step(pStmt) ){
+    rc = execSql(db, sqlite3_column_text(pStmt, 0));
+    if( rc!=SQLITE_OK ){
+      sqlite3_finalize(pStmt);
+      return rc;
+    }
+  }
+
+  return sqlite3_finalize(pStmt);
+}
+
+#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 sqlite3Vacuum(Parse *pParse, Token *pTableName){
+  Vdbe *v = sqlite3GetVdbe(pParse);
+  if( v ){
+    sqlite3VdbeAddOp(v, OP_Vacuum, 0, 0);
+  }
+  return;
+}
+
+/*
+** This routine implements the OP_Vacuum opcode of the VDBE.
+*/
+int sqlite3RunVacuum(char **pzErrMsg, sqlite3 *db){
+  int rc = SQLITE_OK;     /* Return code from service routines */
+#ifndef 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 */
+  Btree *pMain;           /* The database being vacuumed */
+  Btree *pTemp;
+  char *zSql = 0;
+  int writeschema_flag;   /* Saved value of the write-schema flag */
+
+  /* Save the current value of the write-schema flag before setting it. */
+  writeschema_flag = db->flags&SQLITE_WriteSchema;
+  db->flags |= SQLITE_WriteSchema;
+
+  if( !db->autoCommit ){
+    sqlite3SetString(pzErrMsg, "cannot VACUUM from within a transaction", 
+       (char*)0);
+    rc = SQLITE_ERROR;
+    goto end_of_vacuum;
+  }
+
+  /* Get the full pathname of the database file and create a
+  ** temporary filename in the same directory as the original file.
+  */
+  pMain = db->aDb[0].pBt;
+  zFilename = sqlite3BtreeGetFilename(pMain);
+  assert( zFilename );
+  if( zFilename[0]=='\0' ){
+    /* The in-memory database. Do nothing. Return directly to avoid causing
+    ** an error trying to DETACH the vacuum_db (which never got attached)
+    ** in the exit-handler.
+    */
+    return SQLITE_OK;
+  }
+  nFilename = strlen(zFilename);
+  zTemp = sqliteMalloc( nFilename+100 );
+  if( zTemp==0 ){
+    rc = SQLITE_NOMEM;
+    goto end_of_vacuum;
+  }
+  strcpy(zTemp, zFilename);
+
+  /* The randomName() procedure in the following loop uses an excellent
+  ** source of randomness to generate a name from a space of 1.3e+31 
+  ** possibilities.  So unless the directory already contains on the order
+  ** of 1.3e+31 files, the probability that the following loop will
+  ** run more than once or twice is vanishingly small.  We are certain
+  ** enough that this loop will always terminate (and terminate quickly)
+  ** that we don't even bother to set a maximum loop count.
+  */
+  do {
+    zTemp[nFilename] = '-';
+    randomName((unsigned char*)&zTemp[nFilename+1]);
+  } while( sqlite3OsFileExists(zTemp) );
+
+  /* Attach the temporary database as 'vacuum_db'. The synchronous pragma
+  ** can be set to 'off' for this file, as it is not recovered if a crash
+  ** occurs anyway. The integrity of the database is maintained by a
+  ** (possibly synchronous) transaction opened on the main database before
+  ** sqlite3BtreeCopyFile() is called.
+  **
+  ** An optimisation would be to use a non-journaled pager.
+  */
+  zSql = sqlite3MPrintf("ATTACH '%q' AS vacuum_db;", zTemp);
+  if( !zSql ){
+    rc = SQLITE_NOMEM;
+    goto end_of_vacuum;
+  }
+  rc = execSql(db, zSql);
+  sqliteFree(zSql);
+  zSql = 0;
+  if( rc!=SQLITE_OK ) goto end_of_vacuum;
+  assert( strcmp(db->aDb[db->nDb-1].zName,"vacuum_db")==0 );
+  pTemp = db->aDb[db->nDb-1].pBt;
+  sqlite3BtreeSetPageSize(pTemp, sqlite3BtreeGetPageSize(pMain),
+     sqlite3BtreeGetReserve(pMain));
+  assert( sqlite3BtreeGetPageSize(pTemp)==sqlite3BtreeGetPageSize(pMain) );
+  execSql(db, "PRAGMA vacuum_db.synchronous=OFF");
+
+#ifndef SQLITE_OMIT_AUTOVACUUM
+  sqlite3BtreeSetAutoVacuum(pTemp, sqlite3BtreeGetAutoVacuum(pMain));
+#endif
+
+  /* Begin a transaction */
+  rc = execSql(db, "BEGIN;");
+  if( rc!=SQLITE_OK ) goto end_of_vacuum;
+
+  /* Query the schema of the main database. Create a mirror schema
+  ** in the temporary database.
+  */
+  rc = execExecSql(db, 
+      "SELECT 'CREATE TABLE vacuum_db.' || substr(sql,14,100000000) "
+      "  FROM sqlite_master WHERE type='table' AND name!='sqlite_sequence'");
+  if( rc!=SQLITE_OK ) goto end_of_vacuum;
+  rc = execExecSql(db, 
+      "SELECT 'CREATE INDEX vacuum_db.' || substr(sql,14,100000000)"
+      "  FROM sqlite_master WHERE sql LIKE 'CREATE INDEX %' ");
+  if( rc!=SQLITE_OK ) goto end_of_vacuum;
+  rc = execExecSql(db, 
+      "SELECT 'CREATE UNIQUE INDEX vacuum_db.' || substr(sql,21,100000000) "
+      "  FROM sqlite_master WHERE sql LIKE 'CREATE UNIQUE INDEX %'");
+  if( rc!=SQLITE_OK ) goto end_of_vacuum;
+  rc = execExecSql(db, 
+      "SELECT 'CREATE VIEW vacuum_db.' || substr(sql,13,100000000) "
+      "  FROM sqlite_master WHERE type='view'"
+  );
+  if( rc!=SQLITE_OK ) goto end_of_vacuum;
+
+  /* Loop through the tables in the main database. For each, do
+  ** an "INSERT INTO vacuum_db.xxx SELECT * FROM xxx;" to copy
+  ** the contents to the temporary database.
+  */
+  rc = execExecSql(db, 
+      "SELECT 'INSERT INTO vacuum_db.' || quote(name) "
+      "|| ' SELECT * FROM ' || quote(name) || ';'"
+      "FROM sqlite_master "
+      "WHERE type = 'table' AND name!='sqlite_sequence';"
+  );
+  if( rc!=SQLITE_OK ) goto end_of_vacuum;
+
+  /* Copy over the sequence table
+  */
+  rc = execExecSql(db, 
+      "SELECT 'DELETE FROM vacuum_db.' || quote(name) || ';' "
+      "FROM vacuum_db.sqlite_master WHERE name='sqlite_sequence' "
+  );
+  if( rc!=SQLITE_OK ) goto end_of_vacuum;
+  rc = execExecSql(db, 
+      "SELECT 'INSERT INTO vacuum_db.' || quote(name) "
+      "|| ' SELECT * FROM ' || quote(name) || ';' "
+      "FROM vacuum_db.sqlite_master WHERE name=='sqlite_sequence';"
+  );
+  if( rc!=SQLITE_OK ) goto end_of_vacuum;
+
+
+  /* Copy the triggers from the main database to the temporary database.
+  ** This was deferred before in case the triggers interfered with copying
+  ** the data. It's possible the indices should be deferred until this
+  ** point also.
+  */
+  rc = execExecSql(db, 
+      "SELECT 'CREATE TRIGGER  vacuum_db.' || substr(sql, 16, 1000000) "
+      "FROM sqlite_master WHERE type='trigger'"
+  );
+  if( rc!=SQLITE_OK ) goto end_of_vacuum;
+
+
+  /* At this point, unless the main db was completely empty, there is now a
+  ** transaction open on the vacuum database, but not on the main database.
+  ** Open a btree level transaction on the main database. This allows a
+  ** call to sqlite3BtreeCopyFile(). The main database btree level
+  ** transaction is then committed, so the SQL level never knows it was
+  ** opened for writing. This way, the SQL transaction used to create the
+  ** temporary database never needs to be committed.
+  */
+  if( sqlite3BtreeIsInTrans(pTemp) ){
+    u32 meta;
+    int i;
+
+    /* This array determines which meta meta values are preserved in the
+    ** vacuum.  Even entries are the meta value number and odd entries
+    ** are an increment to apply to the meta value after the vacuum.
+    ** The increment is used to increase the schema cookie so that other
+    ** connections to the same database will know to reread the schema.
+    */
+    static const unsigned char aCopy[] = {
+       1, 1,    /* Add one to the old schema cookie */
+       3, 0,    /* Preserve the default page cache size */
+       5, 0,    /* Preserve the default text encoding */
+       6, 0,    /* Preserve the user version */
+    };
+
+    assert( 0==sqlite3BtreeIsInTrans(pMain) );
+    rc = sqlite3BtreeBeginTrans(pMain, 1);
+    if( rc!=SQLITE_OK ) goto end_of_vacuum;
+
+    /* Copy Btree meta values */
+    for(i=0; i<sizeof(aCopy)/sizeof(aCopy[0]); i+=2){
+      rc = sqlite3BtreeGetMeta(pMain, aCopy[i], &meta);
+      if( rc!=SQLITE_OK ) goto end_of_vacuum;
+      rc = sqlite3BtreeUpdateMeta(pTemp, aCopy[i], meta+aCopy[i+1]);
+    }
+
+    rc = sqlite3BtreeCopyFile(pMain, pTemp);
+    if( rc!=SQLITE_OK ) goto end_of_vacuum;
+    rc = sqlite3BtreeCommit(pMain);
+  }
+
+end_of_vacuum:
+  /* Restore the original value of the write-schema flag. */
+  db->flags &= ~SQLITE_WriteSchema;
+  db->flags |= writeschema_flag;
+
+  /* Currently there is an SQL level transaction open on the vacuum
+  ** database. No locks are held on any other files (since the main file
+  ** was committed at the btree level). So it safe to end the transaction
+  ** by manually setting the autoCommit flag to true and detaching the
+  ** vacuum database. The vacuum_db journal file is deleted when the pager
+  ** is closed by the DETACH.
+  */
+  db->autoCommit = 1;
+  if( rc==SQLITE_OK ){
+    rc = execSql(db, "DETACH vacuum_db;");
+  }else{
+    execSql(db, "DETACH vacuum_db;");
+  }
+  if( zTemp ){
+    sqlite3OsDelete(zTemp);
+    sqliteFree(zTemp);
+  }
+  if( zSql ) sqliteFree( zSql );
+  sqlite3ResetInternalSchema(db, 0);
+#endif
+
+  return rc;
+}