From 0d44be7a686244e07f4f146d5a5ff0ec65204f40 Mon Sep 17 00:00:00 2001
From: sniperbeamer <sniperbeamer@b624d157-de02-0410-bad0-e51aec6abb33>
Date: Mon, 18 Jan 2010 21:48:50 +0000
Subject: [PATCH] Make file saving transactional

git-svn-id: https://svn.code.sf.net/p/keepassx/code/trunk@361 b624d157-de02-0410-bad0-e51aec6abb33
---
 src/Kdb3Database.cpp | 85 ++++++++++++++++++++++++++++++--------------
 src/Kdb3Database.h   |  2 ++
 2 files changed, 60 insertions(+), 27 deletions(-)

diff --git a/src/Kdb3Database.cpp b/src/Kdb3Database.cpp
index e614268..86913bc 100644
--- a/src/Kdb3Database.cpp
+++ b/src/Kdb3Database.cpp
@@ -518,12 +518,6 @@ bool Kdb3Database::load(QString identifier, bool readOnly){
 	return false;
 
 bool Kdb3Database::loadReal(QString filename, bool readOnly, bool differentEncoding) {
-	unsigned long total_size,crypto_size;
-	quint32 Signature1,Signature2,Version,NumGroups,NumEntries,Flags;
-	quint8 FinalRandomSeed[16];
-	quint8 ContentsHash[32];
-	quint8 EncryptionIV[16];
-	
 	File = new QFile(filename);
 	if (readOnly) {
 		if(!File->open(QIODevice::ReadOnly)){
@@ -547,6 +541,14 @@ bool Kdb3Database::loadReal(QString filename, bool readOnly, bool differentEncod
 		}
 	}
 	
+	openedReadOnly = readOnly;
+	
+	unsigned long total_size,crypto_size;
+	quint32 Signature1,Signature2,Version,NumGroups,NumEntries,Flags;
+	quint8 FinalRandomSeed[16];
+	quint8 ContentsHash[32];
+	quint8 EncryptionIV[16];
+	
 	total_size=File->size();
 	char* buffer = new char[total_size];
 	File->read(buffer,total_size);
@@ -1352,6 +1354,18 @@ bool Kdb3Database::save(){
 		return false;
 	}
 	
+	if (!File->isOpen()) {
+		if(!File->open(QIODevice::ReadWrite)){
+			error=tr("Could not open file.");
+			return false;
+		}
+	}
+	
+	if(!(File->openMode() & QIODevice::WriteOnly)){
+		error = tr("The database has been opened read-only.");
+		return false;
+	}
+	
 	//Delete old backup entries
 	if (config->backup() && config->backupDelete() && config->backupDeleteAfter()>0 && backupGroup()){
 		QDateTime time = QDateTime::currentDateTime().addDays(-config->backupDeleteAfter());
@@ -1367,11 +1381,6 @@ bool Kdb3Database::save(){
 	quint8 ContentsHash[32];
 	quint8 EncryptionIV[16];
 
-	if(!(File->openMode() & QIODevice::WriteOnly)){
-		error = tr("The database has been opened read-only.");
-		return false;
-	}
-
 	unsigned int FileSize;
 
 	QList<StdEntry> MetaStreams;
@@ -1488,31 +1497,53 @@ bool Kdb3Database::save(){
 	
 	int size = EncryptedPartSize+DB_HEADER_SIZE;
 	
-	if (!File->resize(size)){
-		// only recreate file if the new database is smaller
-		if (File->size() > size) {
-			qDebug("Unable to resize, trying to recreate file");
-			if (!File->remove() || !File->open(QIODevice::ReadWrite)) {
-				delete [] buffer;
-				error=decodeFileError(File->error());
-				return false;
-			}
-		}
-	}
-	File->seek(0);
-	if (File->write(buffer,size)!=size){
-		delete [] buffer;
+	if (!saveFileTransactional(buffer, size)) {
 		error=decodeFileError(File->error());
+		delete [] buffer;
 		return false;
 	}
-	if (!syncFile(File))
-		qWarning("Unable to flush file to disk");
 
 	delete [] buffer;
 	//if(SearchGroupID!=-1)Groups.push_back(SearchGroup);
 	return true;
 }
 
+bool Kdb3Database::saveFileTransactional(char* buffer, int size) {
+	QString orgFilename = File->fileName();
+	QFile* tmpFile = new QFile(orgFilename + ".tmp");
+	if (!tmpFile->open(QIODevice::WriteOnly|QIODevice::Truncate)) {
+		tmpFile->remove();
+		delete tmpFile;
+		return false;
+	}
+	if (tmpFile->write(buffer,size) != size) {
+		tmpFile->remove();
+		delete tmpFile;
+		return false;
+	}
+	if (!syncFile(tmpFile))
+		qWarning("Unable to flush file to disk");
+	tmpFile->close();
+	if (!File->remove()) {
+		delete tmpFile;
+		return false;
+	}
+	delete File;
+	File = NULL;
+	if (!tmpFile->rename(orgFilename)) {
+		delete tmpFile;
+		File = new QFile(orgFilename);
+		return false;
+	}
+	File = tmpFile;
+	if (!tmpFile->open(QIODevice::ReadWrite)) {
+		delete tmpFile;
+		return false;
+	}
+	
+	return true;
+}
+
 void Kdb3Database::createCustomIconsMetaStream(StdEntry* e){
 	/* Rev 3 */
 	e->BinaryDesc="bin-stream";
diff --git a/src/Kdb3Database.h b/src/Kdb3Database.h
index ca96db9..4e05087 100644
--- a/src/Kdb3Database.h
+++ b/src/Kdb3Database.h
@@ -138,6 +138,7 @@ public:
 	virtual ~Kdb3Database(){};
 	virtual bool load(QString identifier, bool readOnly);
 	virtual bool save();
+	virtual bool saveFileTransactional(char* buffer, int size);
 	virtual bool close();
 	virtual void create();
 	virtual int numEntries();
@@ -236,6 +237,7 @@ private:
 	StdGroup RootGroup;
 	QList<QPixmap>CustomIcons;
 	QFile* File;
+	bool openedReadOnly;
 	QString error;
 	bool KeyError;
 	bool PotentialEncodingIssueLatin1;