improve sync locking and status messages

1 files changed, 115 insertions, 30 deletions

diff --git a/smartpensyncer.cc b/smartpensyncer.cc
index 551162e..cdf9bc6 100644
--- a/smartpensyncer.cc
+++ b/smartpensyncer.cc
@@ -21,6 +21,7 @@
 #include <QtCore/QThread>
 #include <QtCore/QDebug>
 #include <quazip/quazipfile.h>
+#include <cstdio>
 #include "paperreplay.h"
 #include "notebookmodel.h"
 #include "smartpensyncer.h"
@@ -28,33 +29,98 @@
 #define BUFFER_SIZE 16 * 1024
 
 namespace {
-static QDateTime getTimestampFileDate(const QString &path)
+class LockFile
 {
-	QFileInfo info(path);
-	qDebug() << "Checking timestamp" << info.filePath();
+public:
+	LockFile(const QString &path);
+	~LockFile();
+
+	bool lock();
+
+private:
+	QString _path;
+	FILE * _file;
+	bool _locked;
+};
+
+class TimestampFile
+{
+public:
+	TimestampFile(const QString &path);
+
+	QDateTime get();
+	void set();
+
+private:
+	QFileInfo _fi;
+};
+
+LockFile::LockFile(const QString &path)
+    : _path(path), _file(0), _locked(false)
+{
+
+}
+
+LockFile::~LockFile()
+{
+	if (_file) {
+		fclose(_file);
+	}
+	if (_locked) {
+		if (!QFile::remove(_path)) {
+			qWarning() << "Cannot remove lock file:" << _path;
+		}
+	}
+}
+
+bool LockFile::lock()
+{
+	Q_ASSERT(!_locked);
+
+	QFileInfo info(_path);
 	if (info.exists()) {
-		return info.lastModified();
+		if (info.created().secsTo(QDateTime::currentDateTime()) > 10 * 60) {
+			if (QFile::remove(info.filePath())) {
+				qDebug() << "Removing stale lock file:" << info.absoluteFilePath();
+			}
+		} else {
+			return false;
+		}
+	}
+
+	_file = ::fopen(info.absoluteFilePath().toLocal8Bit().data(), "wx");
+	if (_file) {
+		_locked = true;
+		return true;
 	} else {
-		return QDateTime();
+		return false;
 	}
 }
 
-static void setTimestampFileDate(const QString &path)
+TimestampFile::TimestampFile(const QString &path)
+    : _fi(path)
 {
-	QFile f(path);
-	if (!f.open(QIODevice::WriteOnly | QIODevice::Truncate)) {
-		qWarning() << "Could not set timestamp file:" << path;
-		return;
+}
+
+QDateTime TimestampFile::get()
+{
+	qDebug() << "Checking timestamp" << _fi.filePath();
+	if (_fi.exists()) {
+		return _fi.lastModified();
+	} else {
+		return QDateTime();
 	}
-	f.close();
 }
 
-void removeTimestampFile(const QString &path)
+void TimestampFile::set()
 {
-	QFile f(path);
-	if (!f.remove()) {
-		qWarning() << "Cannot remove timestamp file:" << path;
+	QFile f(_fi.filePath());
+	if (!f.open(QIODevice::WriteOnly | QIODevice::Truncate)) {
+		qWarning() << "Could not set timestamp file:" << _fi.absoluteFilePath();
+		return;
 	}
+	f.close();
+	_fi.refresh();
 }
 }
 
@@ -81,6 +147,11 @@ QString SmartpenSyncer::penName() const
 	return _penName;
 }
 
+bool SmartpenSyncer::hasErrors() const
+{
+	return _errored;
+}
+
 void SmartpenSyncer::abort()
 {
 	_aborted = true;
@@ -123,10 +194,14 @@ void SmartpenSyncer::run()
 
 bool SmartpenSyncer::syncPen()
 {
-	QDateTime lastSyncTime = getTimestampFileDate(_penDataDir.filePath(".lastsync"));
-	QList<Smartpen::ChangeReport> changes = _pen->getChangeList(lastSyncTime);
+	LockFile lock(_penDataDir.filePath(".sync.lck"));
+	if (!lock.lock()) {
+		qWarning() << "Pen is already being synchronized; delete this file if it is not:" << _penDataDir.absoluteFilePath(".sync.lck");
+		return false;
+	}
 
-	setTimestampFileDate(_penDataDir.filePath(".sync.lck"));
+	TimestampFile lastSync(_penDataDir.filePath(".lastsync"));
+	QList<Smartpen::ChangeReport> changes = _pen->getChangeList(lastSync.get());
 
 	foreach(const Smartpen::ChangeReport &change, changes) {
 		if (!change.guid.isEmpty()) {
@@ -140,10 +215,14 @@ bool SmartpenSyncer::syncPen()
 				return false;
 			}
 		}
+
+		if (_aborted) {
+			qWarning() << "Aborting sync";
+			return false;
+		}
 	}
 
-	setTimestampFileDate(_penDataDir.filePath(".lastsync"));
-	removeTimestampFile(_penDataDir.filePath(".sync.lck"));
+	lastSync.set();
 
 	return true;
 }
@@ -157,17 +236,20 @@ bool SmartpenSyncer::syncNotebook(const Smartpen::ChangeReport &change)
 		}
 	}
 
-	setTimestampFileDate(notebookDir.filePath(".sync.lck"));
+	LockFile lock(notebookDir.filePath(".sync.lck"));
+	if (!lock.lock()) {
+		qWarning() << "Notebook is already being synchronized; delete this file if it is not:" << notebookDir.absoluteFilePath(".sync.lck");
+		return false;
+	}
 
-	QDateTime lastSyncTime = getTimestampFileDate(notebookDir.filePath(".lastsync"));
-	QByteArray lspData = _pen->getLspData(change.guid, lastSyncTime);
+	TimestampFile lastSync(notebookDir.filePath(".lastsync"));
+	QByteArray lspData = _pen->getLspData(change.guid, lastSync.get());
 
 	if (!extractZip(lspData, notebookDir)) {
 		return false;
 	}
 
-	setTimestampFileDate(notebookDir.filePath(".lastsync"));
-	removeTimestampFile(notebookDir.filePath(".sync.lck"));
+	lastSync.set();
 
 	return true;
 }
@@ -181,17 +263,20 @@ bool SmartpenSyncer::syncPaperReplay()
 		}
 	}
 
-	setTimestampFileDate(replayDir.filePath(".sync.lck"));
+	LockFile lock(replayDir.filePath(".sync.lck"));
+	if (!lock.lock()) {
+		qWarning() << "Paper replay is already being synchronized; delete this file if it is not:" << replayDir.absoluteFilePath(".sync.lck");
+		return false;
+	}
 
-	QDateTime lastSyncTime = getTimestampFileDate(replayDir.filePath(".lastsync"));
-	QByteArray replayData = _pen->getPaperReplay(lastSyncTime);
+	TimestampFile lastSync(replayDir.filePath(".lastsync"));
+	QByteArray replayData = _pen->getPaperReplay(lastSync.get());
 
 	if (!extractZip(replayData, replayDir)) {
 		return false;
 	}
 
-	setTimestampFileDate(replayDir.filePath(".lastsync"));
-	removeTimestampFile(replayDir.filePath(".sync.lck"));
+	lastSync.set();
 
 	return true;
 }