[libgda] SQLite provider: better BLOB handling regarding transactions

[Vivien Malerba <vivien src gnome org>]

commit 644a09dde69bd27c4c28b0ab1d0bc76399d50614
Author: Vivien Malerba <malerba gnome-db org>
Date:   Tue Sep 22 21:41:06 2009 +0200

    SQLite provider: better BLOB handling regarding transactions
    
    Start a transaction before reading any BLOB from an SQLite
    database, and don't start a transaction when using a BLOB as a
    variable

 libgda/sqlite/gda-sqlite-blob-op.c  |   27 +++++++++++++-
 libgda/sqlite/gda-sqlite-blob-op.h  |    5 ++-
 libgda/sqlite/gda-sqlite-provider.c |   64 ++++++++++-------------------------
 libgda/sqlite/gda-sqlite.h          |    3 +-
 4 files changed, 48 insertions(+), 51 deletions(-)
---
diff --git a/libgda/sqlite/gda-sqlite-blob-op.c b/libgda/sqlite/gda-sqlite-blob-op.c
index cf9343d..bc21ce1 100644
--- a/libgda/sqlite/gda-sqlite-blob-op.c
+++ b/libgda/sqlite/gda-sqlite-blob-op.c
@@ -112,15 +112,33 @@ gda_sqlite_blob_op_finalize (GObject * object)
 	parent_class->finalize (object);
 }
 
+static gboolean
+check_transaction_started (GdaConnection *cnc, gboolean *out_started)
+{
+        GdaTransactionStatus *trans;
+
+        trans = gda_connection_get_transaction_status (cnc);
+        if (!trans) {
+		if (!gda_connection_begin_transaction (cnc, NULL,
+						       GDA_TRANSACTION_ISOLATION_UNKNOWN, NULL))
+			return FALSE;
+		else
+			*out_started = TRUE;
+	}
+	return TRUE;
+}
+
 GdaBlobOp *
-_gda_sqlite_blob_op_new (SqliteConnectionData *cdata, const gchar *db_name, const gchar *table_name,
-			const gchar *column_name, sqlite3_int64 rowid)
+_gda_sqlite_blob_op_new (SqliteConnectionData *cdata,
+			 const gchar *db_name, const gchar *table_name,
+			 const gchar *column_name, sqlite3_int64 rowid)
 {
 	GdaSqliteBlobOp *bop = NULL;
 	int rc;
 	sqlite3_blob *sblob;
 	gchar *db, *table;
 	gboolean free_strings = TRUE;
+	gboolean transaction_started = FALSE;
 
 	g_return_val_if_fail (table_name, NULL);
 	g_return_val_if_fail (column_name, NULL);
@@ -133,11 +151,16 @@ _gda_sqlite_blob_op_new (SqliteConnectionData *cdata, const gchar *db_name, cons
 	else if (! _split_identifier_string (g_strdup (table_name), &db, &table))
 		return NULL;
 
+	if (! check_transaction_started (cdata->gdacnc, &transaction_started))
+		return NULL;
+
 	rc = sqlite3_blob_open (cdata->connection, db ? db : "main", table, column_name, rowid,
 				1, /* Read & Write */
 				&(sblob));
 	if (rc != SQLITE_OK) {
 		/*g_print ("ERROR: %s\n", sqlite3_errmsg (cdata->connection));*/
+		if (transaction_started)
+			gda_connection_rollback_transaction (cdata->gdacnc, NULL, NULL);
 		goto out;
 	}
 
diff --git a/libgda/sqlite/gda-sqlite-blob-op.h b/libgda/sqlite/gda-sqlite-blob-op.h
index 48d6aca..306bb2c 100644
--- a/libgda/sqlite/gda-sqlite-blob-op.h
+++ b/libgda/sqlite/gda-sqlite-blob-op.h
@@ -47,8 +47,9 @@ struct _GdaSqliteBlobOpClass {
 };
 
 GType         _gda_sqlite_blob_op_get_type     (void) G_GNUC_CONST;
-GdaBlobOp    *_gda_sqlite_blob_op_new          (SqliteConnectionData *cdata, const gchar *db_name, const gchar *table_name,
-					       const gchar *column_name, sqlite3_int64 rowid);
+GdaBlobOp    *_gda_sqlite_blob_op_new          (SqliteConnectionData *cdata,
+						const gchar *db_name, const gchar *table_name,
+						const gchar *column_name, sqlite3_int64 rowid);
 
 G_END_DECLS
 
diff --git a/libgda/sqlite/gda-sqlite-provider.c b/libgda/sqlite/gda-sqlite-provider.c
index 3d105c4..58823d1 100644
--- a/libgda/sqlite/gda-sqlite-provider.c
+++ b/libgda/sqlite/gda-sqlite-provider.c
@@ -618,6 +618,8 @@ gda_sqlite_provider_open_connection (GdaServerProvider *provider, GdaConnection
 	}
 
 	cdata = g_new0 (SqliteConnectionData, 1);
+	cdata->gdacnc = cnc;
+	g_object_add_weak_pointer (G_OBJECT (cnc), (gpointer*) &(cdata->gdacnc));
 
 	if (filename)
 		cdata->file = filename;
@@ -1031,6 +1033,7 @@ gda_sqlite_provider_begin_transaction (GdaServerProvider *provider, GdaConnectio
 			status = FALSE;
 	}
 
+	/*g_print ("%s(%p) => %s\n", __FUNCTION__, cnc, status ? "TRUE" : "FALSE");*/
 	return status;
 }
 
@@ -1065,6 +1068,7 @@ gda_sqlite_provider_commit_transaction (GdaServerProvider *provider, GdaConnecti
 			status = FALSE;
 	}
 
+	/*g_print ("%s(%p) => %s\n", __FUNCTION__, cnc, status ? "TRUE" : "FALSE");*/
 	return status;
 }
 
@@ -1100,6 +1104,7 @@ gda_sqlite_provider_rollback_transaction (GdaServerProvider *provider,
 			status = FALSE;
 	}
 
+	/*g_print ("%s(%p) => %s\n", __FUNCTION__, cnc, status ? "TRUE" : "FALSE");*/
 	return status;
 }
 
@@ -2111,23 +2116,6 @@ fill_blob_data (GdaConnection *cnc, GdaSet *params,
 	return NULL;
 }
 
-static gboolean
-check_transaction_started (GdaConnection *cnc, gboolean *out_started)
-{
-        GdaTransactionStatus *trans;
-
-        trans = gda_connection_get_transaction_status (cnc);
-        if (!trans) {
-                if (!gda_connection_begin_transaction (cnc, NULL,
-                                                       GDA_TRANSACTION_ISOLATION_UNKNOWN, NULL))
-                        return FALSE;
-                else
-                        *out_started = TRUE;
-        }
-        return TRUE;
-}
-
-
 /*
  * Execute statement request
  */
@@ -2254,7 +2242,6 @@ gda_sqlite_provider_statement_execute (GdaServerProvider *provider, GdaConnectio
 	GdaConnectionEvent *event = NULL;
 	int i;
 	GSList *blobs_list = NULL; /* list of PendingBlob structures */
-	gboolean transaction_started = FALSE;
 
 	for (i = 1, list = _GDA_PSTMT (ps)->param_ids; list; list = list->next, i++) {
 		const gchar *pname = (gchar *) list->data;
@@ -2351,21 +2338,16 @@ gda_sqlite_provider_statement_execute (GdaServerProvider *provider, GdaConnectio
 			GdaBlob *blob = (GdaBlob*) gda_value_get_blob (value);
 			const gchar *str = NULL;
 
-			/* Start a transaction if necessary */
-                        if (!check_transaction_started (cnc, &transaction_started))
-				str = _("Cannot start transaction");
-			else {
-				/* force reading the complete BLOB into memory */
-				if (blob->op)
-					blob_len = gda_blob_op_get_length (blob->op);
-				else
-					blob_len = ((GdaBinary*) blob)->binary_length;
-				if (blob_len < 0) 
-					str = _("Can't get BLOB's length");
-				else if (blob_len >= G_MAXINT)
-					str = _("BLOB is too big");
-			}
-				
+			/* force reading the complete BLOB into memory */
+			if (blob->op)
+				blob_len = gda_blob_op_get_length (blob->op);
+			else
+				blob_len = ((GdaBinary*) blob)->binary_length;
+			if (blob_len < 0) 
+				str = _("Can't get BLOB's length");
+			else if (blob_len >= G_MAXINT)
+				str = _("BLOB is too big");
+
 			if (str) {
 				event = gda_connection_event_new (GDA_CONNECTION_EVENT_ERROR);
 				gda_connection_event_set_description (event, str);
@@ -2462,8 +2444,6 @@ gda_sqlite_provider_statement_execute (GdaServerProvider *provider, GdaConnectio
 		if (new_ps)
 			g_object_unref (ps);
 		pending_blobs_free_list (blobs_list);
-		if (transaction_started)
-                        gda_connection_rollback_transaction (cnc, NULL, NULL);
 		return NULL;
 	}
 	
@@ -2493,8 +2473,6 @@ gda_sqlite_provider_statement_execute (GdaServerProvider *provider, GdaConnectio
 		if (allow_noparam)
 			g_object_set (data_model, "auto-reset", TRUE, NULL);
 		pending_blobs_free_list (blobs_list);
-		if (transaction_started)
-			gda_connection_commit_transaction (cnc, NULL, NULL);
 		return data_model;
         }
 	else {
@@ -2518,8 +2496,6 @@ gda_sqlite_provider_statement_execute (GdaServerProvider *provider, GdaConnectio
 				if (new_ps)
 					g_object_unref (ps);
 				pending_blobs_free_list (blobs_list);
-				if (transaction_started)
-					gda_connection_rollback_transaction (cnc, NULL, NULL);
 				return NULL;
                         }
 			else {
@@ -2529,8 +2505,6 @@ gda_sqlite_provider_statement_execute (GdaServerProvider *provider, GdaConnectio
 				if (new_ps)
 					g_object_unref (ps);
 				pending_blobs_free_list (blobs_list);
-				if (transaction_started)
-					gda_connection_rollback_transaction (cnc, NULL, NULL);
 				return NULL;
 			}
                 }
@@ -2542,8 +2516,6 @@ gda_sqlite_provider_statement_execute (GdaServerProvider *provider, GdaConnectio
 				sqlite3_reset (ps->sqlite_stmt);
 				if (new_ps)
 					g_object_unref (ps);
-				if (transaction_started)
-					gda_connection_rollback_transaction (cnc, NULL, NULL);
 				return NULL;
 			}
 			
@@ -2585,8 +2557,6 @@ gda_sqlite_provider_statement_execute (GdaServerProvider *provider, GdaConnectio
 			sqlite3_reset (ps->sqlite_stmt);
 			if (new_ps)
 				g_object_unref (ps);
-			if (transaction_started)
-				gda_connection_commit_transaction (cnc, NULL, NULL);
 			return set;
 		}
 	}
@@ -2933,7 +2903,9 @@ gda_sqlite_free_cnc_data (SqliteConnectionData *cdata)
 {
 	if (!cdata)
 		return;
-
+	
+	if (cdata->gdacnc)
+		g_object_remove_weak_pointer (G_OBJECT (cdata->gdacnc), (gpointer*) &(cdata->gdacnc));
 	if (cdata->connection) 
 		sqlite3_close (cdata->connection);
 	g_free (cdata->file);
diff --git a/libgda/sqlite/gda-sqlite.h b/libgda/sqlite/gda-sqlite.h
index c9f3237..30aa7c2 100644
--- a/libgda/sqlite/gda-sqlite.h
+++ b/libgda/sqlite/gda-sqlite.h
@@ -1,5 +1,5 @@
 /* GDA SQLite provider
- * Copyright (C) 1998 - 2008 The GNOME Foundation.
+ * Copyright (C) 1998 - 2009 The GNOME Foundation.
  *
  * AUTHORS:
  *	Rodrigo Moya <rodrigo gnome-db org>
@@ -41,6 +41,7 @@
  * Provider's specific connection data
  */
 typedef struct {
+	GdaConnection *gdacnc;
 	sqlite3      *connection;
 	gchar        *file;
 	GHashTable   *types; /* key = type name, value = GType */