Merge branch 'master' of https://github.com/FirebirdSQL/firebird.git

examples/interfaces/07.blob.cpp

@@ -0,0 +1,187 @@
+/*
+ *	PROGRAM:	Object oriented API samples.
+ *	MODULE:		07.blob.cpp
+ *	DESCRIPTION:	A sample of loading data into blob and reading.
+ *					Run second time (when database already exists) to see
+ *					how FbException is caught and handled by this code.
+ *
+ *					Example for the following interfaces:
+ *					IAttachment - use of open and create blob methods
+ *					IBlob - interface to work with blobs
+ *
+ *  The contents of this file are subject to the Initial
+ *  Developer's Public License Version 1.0 (the "License");
+ *  you may not use this file except in compliance with the
+ *  License. You may obtain a copy of the License at
+ *  http://www.ibphoenix.com/main.nfs?a=ibphoenix&page=ibp_idpl.
+ *
+ *  Software distributed under the License is distributed AS IS,
+ *  WITHOUT WARRANTY OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing rights
+ *  and limitations under the License.
+ *
+ *  The Original Code was created by Alexander Peshkoff
+ *  for the Firebird Open Source RDBMS project.
+ *
+ *  Copyright (c) 2016 Alexander Peshkoff <peshkoff@mail.ru>
+ *  and all contributors signed below.
+ *
+ *  All Rights Reserved.
+ *  Contributor(s): ______________________________________.
+ */
+
+#include "ifaceExamples.h"
+#include <firebird/Message.h>
+
+static IMaster* master = fb_get_master_interface();
+
+static const char* testData[] = {
+	"This is test data",
+	"that is inserted during example execution",
+	"into blobs_table",
+	NULL
+};
+
+static void errPrint(IStatus* status)
+{
+	char buf[256];
+	master->getUtilInterface()->formatStatus(buf, sizeof(buf), status);
+	fprintf(stderr, "%s\n", buf);
+}
+
+static void drop(IAttachment** att)
+{
+	// With CheckStatusWrapper passed as status interface noting is thrown on error
+	// You should check status yourself
+	CheckStatusWrapper status(master->getStatus());
+
+	// drop database (will close interface)
+	(*att)->dropDatabase(&status);
+	if (status.getState() && IStatus::STATE_ERRORS)
+	{
+		errPrint(&status);
+		fprintf(stderr, "*** Drop database failed - do it manually before next run ***\n");
+	}
+	else
+		*att = NULL;
+
+	// cleanup
+	status.dispose();
+}
+
+int main()
+{
+	int rc = 0;
+
+	// set default password if none specified in environment
+	setenv("ISC_USER", "sysdba", 0);
+	setenv("ISC_PASSWORD", "masterkey", 0);
+
+	// With ThrowStatusWrapper passed as status interface FbException will be thrown on error
+	ThrowStatusWrapper status(master->getStatus());
+
+	// Declare pointers to required interfaces
+	IProvider* prov = master->getDispatcher();
+	IAttachment* att = NULL;
+	ITransaction* tra = NULL;
+	IBlob* blob = NULL;
+
+	try
+	{
+		// create database
+		att = prov->createDatabase(&status, "blob_07.fdb", 0, NULL);
+		tra = att->startTransaction(&status, 0, NULL);
+
+		// create table
+		att->execute(&status, tra, 0, "create table blobs_table (b blob sub_type text)", SAMPLES_DIALECT,
+			NULL, NULL, NULL, NULL);
+		tra->commitRetaining(&status);
+
+		// Message for data exchange
+		FB_MESSAGE(Msg, ThrowStatusWrapper,
+			(FB_BLOB, b)
+		) message(&status, master);
+		message.clear();
+
+		// create blob
+		blob = att->createBlob(&status, tra, &message->b, 0, NULL);
+
+		// populate blob with data
+		for (const char** seg = testData; *seg; ++seg)
+			blob->putSegment(&status, strlen(*seg), *seg);
+		blob->close(&status);
+		blob = NULL;
+
+		// insert blob into the table
+		att->execute(&status, tra, 0, "insert into blobs_table(b) values(?)", SAMPLES_DIALECT,
+			message.getMetadata(), message.getData(), NULL, NULL);
+		tra->commitRetaining(&status);
+		printf("Test blob inserted into blobs_table\n...\n");
+
+		// Read blob from table
+		message.clear();
+		att->execute(&status, tra, 0, "select first(1) b from blobs_table", SAMPLES_DIALECT,
+			NULL, NULL, message.getMetadata(), message.getData());
+		blob = att->openBlob(&status, tra, &message->b, 0, NULL);
+
+		// Read segments from blob
+		// Use very small segment buffer to show read of incomplete segment
+		printf("Read inserted blob from blobs_table\n...\n");
+		int bufOver = 0;
+		for(bool eof = false; !eof; )
+		{
+			const char* lineFeed = "\n";
+			char buf[32];
+			unsigned l = 0;
+			switch (blob->getSegment(&status, sizeof(buf) - 1, buf, &l))
+			{
+				case IStatus::RESULT_OK:
+					break;
+				case IStatus::RESULT_SEGMENT:
+					lineFeed = "";
+					bufOver++;
+					break;
+				default:
+					eof = true;
+					continue;
+			}
+			buf[l] = 0;
+			printf("%s%s", buf, lineFeed);
+		}
+		printf("\nSegment not fit in buffer counter = %d\n\n", bufOver);
+
+		// cleanup
+		blob->close(&status);
+		blob = NULL;
+		tra->commit(&status);
+		tra = NULL;
+
+		// uncomment next line to play with errors during drop database
+		// printf("Attach with any client to blob_07.fdb to prevent it being dropped and press enter"); getchar();
+
+		// drop database
+		drop(&att);
+	}
+	catch (const FbException& error)
+	{
+		// handle error
+		rc = 1;
+		errPrint(error.getStatus());
+
+		if (att)
+			drop(&att);
+	}
+
+	// release interfaces after error caught
+	if (blob)
+		blob->release();
+	if (tra)
+		tra->release();
+	if (att)
+		att->release();
+
+	status.dispose();
+	prov->release();
+
+	return rc;
+}