SQLite: Check-in [de72a773]

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Overview

Comment:	In the sessions module, avoid collecting rebase data if the user has not requested it.
Downloads:	Tarball \| ZIP archive \| SQL archive
Timelines:	family \| ancestors \| descendants \| both \| trunk
Files:	files \| file ages \| folders
SHA3-256:	de72a773dd3ad58a7f2233e1fc06bf60deb8892a2719ea8e9b42e7d592c1279f
User & Date:	dan 2018-10-29 17:08:27

Context

2018-10-29
18:33		Fix minor memory leak in the dbstat extension that can occur following an attempt to analyze a corrupt database file. check-in: cb874fd8 user: drh tags: trunk
17:53		Add the sqlite3_normalized_sql() API. Closed-Leaf check-in: 592b66e8 user: mistachkin tags: normalized_sql
17:08		In the sessions module, avoid collecting rebase data if the user has not requested it. check-in: de72a773 user: dan tags: trunk
16:07		Harden the dbstat extension against corrupt database files. check-in: a0d47f25 user: drh tags: trunk

Changes

Hide Diffs Unified Diffs Ignore Whitespace Patch

Changes to ext/session/sqlite3session.c.

  int nCol;                       /* Size of azCol[] and abPK[] arrays */
  const char **azCol;             /* Array of column names */
  u8 *abPK;                       /* Boolean array - true if column is in PK */
  int bStat1;                     /* True if table is sqlite_stat1 */
  int bDeferConstraints;          /* True to defer constraints */
  SessionBuffer constraints;      /* Deferred constraints are stored here */
  SessionBuffer rebase;           /* Rebase information (if any) here */
  int bRebaseStarted;             /* If table header is already in rebase */

};

/*
** Formulate a statement to DELETE a row from database db. Assuming a table
** structure like this:
**
**     CREATE TABLE x(a, b, c, d, PRIMARY KEY(a, c));
................................................................................
*/
static int sessionRebaseAdd(
  SessionApplyCtx *p,             /* Apply context */
  int eType,                      /* Conflict resolution (OMIT or REPLACE) */
  sqlite3_changeset_iter *pIter   /* Iterator pointing at current change */
){
  int rc = SQLITE_OK;

  int i;
  int eOp = pIter->op;
  if( p->bRebaseStarted==0 ){
    /* Append a table-header to the rebase buffer */
    const char *zTab = pIter->zTab;
    sessionAppendByte(&p->rebase, 'T', &rc);
    sessionAppendVarint(&p->rebase, p->nCol, &rc);
    sessionAppendBlob(&p->rebase, p->abPK, p->nCol, &rc);
    sessionAppendBlob(&p->rebase, (u8*)zTab, (int)strlen(zTab)+1, &rc);
    p->bRebaseStarted = 1;
  }

  assert( eType==SQLITE_CHANGESET_REPLACE||eType==SQLITE_CHANGESET_OMIT );
  assert( eOp==SQLITE_DELETE || eOp==SQLITE_INSERT || eOp==SQLITE_UPDATE );

  sessionAppendByte(&p->rebase, 
      (eOp==SQLITE_DELETE ? SQLITE_DELETE : SQLITE_INSERT), &rc
  );
  sessionAppendByte(&p->rebase, (eType==SQLITE_CHANGESET_REPLACE), &rc);
  for(i=0; i<p->nCol; i++){
    sqlite3_value *pVal = 0;
    if( eOp==SQLITE_DELETE || (eOp==SQLITE_UPDATE && p->abPK[i]) ){
      sqlite3changeset_old(pIter, i, &pVal);
    }else{
      sqlite3changeset_new(pIter, i, &pVal);
    }
    sessionAppendValue(&p->rebase, pVal, &rc);
  }

  return rc;
}

/*
** Invoke the conflict handler for the change that the changeset iterator
** currently points to.
**
................................................................................
  SessionApplyCtx sApply;         /* changeset_apply() context object */
  int bPatchset;

  assert( xConflict!=0 );

  pIter->in.bNoDiscard = 1;
  memset(&sApply, 0, sizeof(sApply));

  sqlite3_mutex_enter(sqlite3_db_mutex(db));
  if( (flags & SQLITE_CHANGESETAPPLY_NOSAVEPOINT)==0 ){
    rc = sqlite3_exec(db, "SAVEPOINT changeset_apply", 0, 0, 0);
  }
  if( rc==SQLITE_OK ){
    rc = sqlite3_exec(db, "PRAGMA defer_foreign_keys = 1", 0, 0, 0);
  }
................................................................................
      rc = sqlite3_exec(db, "RELEASE changeset_apply", 0, 0, 0);
    }else{
      sqlite3_exec(db, "ROLLBACK TO changeset_apply", 0, 0, 0);
      sqlite3_exec(db, "RELEASE changeset_apply", 0, 0, 0);
    }
  }


  if( rc==SQLITE_OK && bPatchset==0 && ppRebase && pnRebase ){
    *ppRebase = (void*)sApply.rebase.aBuf;
    *pnRebase = sApply.rebase.nBuf;
    sApply.rebase.aBuf = 0;
  }
  sqlite3_finalize(sApply.pInsert);
  sqlite3_finalize(sApply.pDelete);
  sqlite3_finalize(sApply.pUpdate);








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  int nCol;                       /* Size of azCol[] and abPK[] arrays */
  const char **azCol;             /* Array of column names */
  u8 *abPK;                       /* Boolean array - true if column is in PK */
  int bStat1;                     /* True if table is sqlite_stat1 */
  int bDeferConstraints;          /* True to defer constraints */
  SessionBuffer constraints;      /* Deferred constraints are stored here */
  SessionBuffer rebase;           /* Rebase information (if any) here */
  u8 bRebaseStarted;              /* If table header is already in rebase */
  u8 bRebase;                     /* True to collect rebase information */
};

/*
** Formulate a statement to DELETE a row from database db. Assuming a table
** structure like this:
**
**     CREATE TABLE x(a, b, c, d, PRIMARY KEY(a, c));
................................................................................
*/
static int sessionRebaseAdd(
  SessionApplyCtx *p,             /* Apply context */
  int eType,                      /* Conflict resolution (OMIT or REPLACE) */
  sqlite3_changeset_iter *pIter   /* Iterator pointing at current change */
){
  int rc = SQLITE_OK;
  if( p->bRebase ){
    int i;
    int eOp = pIter->op;
    if( p->bRebaseStarted==0 ){
      /* Append a table-header to the rebase buffer */
      const char *zTab = pIter->zTab;
      sessionAppendByte(&p->rebase, 'T', &rc);
      sessionAppendVarint(&p->rebase, p->nCol, &rc);
      sessionAppendBlob(&p->rebase, p->abPK, p->nCol, &rc);
      sessionAppendBlob(&p->rebase, (u8*)zTab, (int)strlen(zTab)+1, &rc);
      p->bRebaseStarted = 1;
    }

    assert( eType==SQLITE_CHANGESET_REPLACE||eType==SQLITE_CHANGESET_OMIT );
    assert( eOp==SQLITE_DELETE || eOp==SQLITE_INSERT || eOp==SQLITE_UPDATE );

    sessionAppendByte(&p->rebase, 
        (eOp==SQLITE_DELETE ? SQLITE_DELETE : SQLITE_INSERT), &rc
        );
    sessionAppendByte(&p->rebase, (eType==SQLITE_CHANGESET_REPLACE), &rc);
    for(i=0; i<p->nCol; i++){
      sqlite3_value *pVal = 0;
      if( eOp==SQLITE_DELETE || (eOp==SQLITE_UPDATE && p->abPK[i]) ){
        sqlite3changeset_old(pIter, i, &pVal);
      }else{
        sqlite3changeset_new(pIter, i, &pVal);
      }
      sessionAppendValue(&p->rebase, pVal, &rc);
    }
  }
  return rc;
}

/*
** Invoke the conflict handler for the change that the changeset iterator
** currently points to.
**
................................................................................
  SessionApplyCtx sApply;         /* changeset_apply() context object */
  int bPatchset;

  assert( xConflict!=0 );

  pIter->in.bNoDiscard = 1;
  memset(&sApply, 0, sizeof(sApply));
  sApply.bRebase = (ppRebase && pnRebase);
  sqlite3_mutex_enter(sqlite3_db_mutex(db));
  if( (flags & SQLITE_CHANGESETAPPLY_NOSAVEPOINT)==0 ){
    rc = sqlite3_exec(db, "SAVEPOINT changeset_apply", 0, 0, 0);
  }
  if( rc==SQLITE_OK ){
    rc = sqlite3_exec(db, "PRAGMA defer_foreign_keys = 1", 0, 0, 0);
  }
................................................................................
      rc = sqlite3_exec(db, "RELEASE changeset_apply", 0, 0, 0);
    }else{
      sqlite3_exec(db, "ROLLBACK TO changeset_apply", 0, 0, 0);
      sqlite3_exec(db, "RELEASE changeset_apply", 0, 0, 0);
    }
  }

  assert( sApply.bRebase || sApply.rebase.nBuf==0 );
  if( rc==SQLITE_OK && bPatchset==0 && sApply.bRebase ){
    *ppRebase = (void*)sApply.rebase.aBuf;
    *pnRebase = sApply.rebase.nBuf;
    sApply.rebase.aBuf = 0;
  }
  sqlite3_finalize(sApply.pInsert);
  sqlite3_finalize(sApply.pDelete);
  sqlite3_finalize(sApply.pUpdate);