From 33a6cce45a86b74f2e596253876f8bad71844ea4 Mon Sep 17 00:00:00 2001
From: "Robert C. Helling" <helling@atdotde.de>
Date: Mon, 23 Feb 2015 12:00:55 +0100
Subject: [PATCH 2/4] Save and use database of image hashes.

This patch adds a directory crawler to compute hashes of image files and load and save those to a persistent file.

Signed-off-by: Robert C. Helling <helling@atdotde.de>
---
 qt-ui/divepicturewidget.cpp | 16 +++++++----
 qt-ui/mainwindow.cpp        |  4 +++
 qthelper.cpp                | 70 +++++++++++++++++++++++++++++++++++++++++++++
 qthelper.h                  |  6 ++++
 4 files changed, 90 insertions(+), 6 deletions(-)

diff --git a/qt-ui/divepicturewidget.cpp b/qt-ui/divepicturewidget.cpp
index 4a205da..d4b29e6 100644
--- a/qt-ui/divepicturewidget.cpp
+++ b/qt-ui/divepicturewidget.cpp
@@ -3,22 +3,26 @@
 #include "dive.h"
 #include "divelist.h"
 #include <QtConcurrentMap>
+#include <QtConcurrentRun>
 #include <QDir>
 #include <QCryptographicHash>
 #include <mainwindow.h>
+#include <qthelper.h>
 
 SHashedImage::SHashedImage(struct picture *picture) : QImage(picture->filename)
 {
 	if (isNull()) {
 		// Hash lookup.
+		qDebug() << picture->filename << "not found, trying" << picture->hash << MainWindow::instance()->localFilenameOf[QByteArray::fromHex(picture->hash)];
+		load(MainWindow::instance()->localFilenameOf[QByteArray::fromHex(picture->hash)]);
+		if (!isNull())
+			QtConcurrent::run(updateHash, picture);
 	} else {
-		QCryptographicHash hash(QCryptographicHash::Sha1);
-		QFile imagefile(picture->filename);
-		imagefile.open(QIODevice::ReadOnly);
-		hash.addData(&imagefile);
+		QByteArray hash = hashFile(picture->filename);
 		free(picture->hash);
-		picture->hash = strdup(hash.result().toHex().data());
-		MainWindow::instance()->hashOf.insert(QString(picture->filename), hash.result());
+		picture->hash = strdup(hash.toHex().data());
+		MainWindow::instance()->hashOf.insert(QString(picture->filename), hash);
+		MainWindow::instance()->localFilenameOf[hash] = QString(picture->filename);
 	}
 }
 
diff --git a/qt-ui/mainwindow.cpp b/qt-ui/mainwindow.cpp
index 648ead1..a0fbaeb 100644
--- a/qt-ui/mainwindow.cpp
+++ b/qt-ui/mainwindow.cpp
@@ -37,6 +37,7 @@
 #endif
 #include <QNetworkProxy>
 #include <QUndoStack>
+#include <qthelper.h>
 
 MainWindow *MainWindow::m_Instance = NULL;
 
@@ -50,6 +51,8 @@ MainWindow::MainWindow() : QMainWindow(),
 	Q_ASSERT_X(m_Instance == NULL, "MainWindow", "MainWindow recreated!");
 	m_Instance = this;
 	ui.setupUi(this);
+	read_hashes();
+	learnImages(QDir("/Users/helling/Pictures/subsurfaceimages.away"), 3);
 	// Define the States of the Application Here, Currently the states are situations where the different
 	// widgets will change on the mainwindow.
 
@@ -201,6 +204,7 @@ MainWindow::MainWindow() : QMainWindow(),
 
 MainWindow::~MainWindow()
 {
+	write_hashes();
 	m_Instance = NULL;
 }
 
diff --git a/qthelper.cpp b/qthelper.cpp
index d449268..a58a21d 100644
--- a/qthelper.cpp
+++ b/qthelper.cpp
@@ -22,6 +22,10 @@
 #include <QNetworkAccessManager>
 #include <QUrlQuery>
 #include <QEventLoop>
+#include <QSaveFile>
+#include <QDir>
+#include <QImageReader>
+#include <QtConcurrent>
 
 #include <libxslt/documents.h>
 
@@ -407,3 +411,69 @@ extern "C" char * hashstring(char * filename)
 {
 	return MainWindow::instance()->hashOf[QString(filename)].toHex().data();
 }
+
+void read_hashes()
+{
+	QFile hashfile(QString(system_default_directory()).append("/hashes"));
+	qDebug() << QString(system_default_directory()).append("/hashes");
+	if (hashfile.open(QIODevice::ReadOnly)) {
+		QDataStream stream(&hashfile);
+		stream >> MainWindow::instance()->localFilenameOf;
+		hashfile.close();
+	}
+}
+
+void write_hashes()
+{
+	QSaveFile hashfile(QString(system_default_directory()).append("/hashes"));
+	if (hashfile.open(QIODevice::WriteOnly)) {
+		QDataStream stream(&hashfile);
+		stream << MainWindow::instance()->localFilenameOf;
+		hashfile.commit();
+	} else {
+		qDebug() << "cannot open" << hashfile.fileName();
+	}
+}
+
+QByteArray hashFile(const char *filename)
+{
+	QCryptographicHash hash(QCryptographicHash::Sha1);
+	QFile imagefile(filename);
+	imagefile.open(QIODevice::ReadOnly);
+	hash.addData(&imagefile);
+	return hash.result();
+}
+
+void updateHash(struct picture *picture) {
+	char *old = picture->hash;
+	picture->hash = strdup(hashFile(MainWindow::instance()->localFilenameOf[QByteArray::fromHex(picture->hash)].toUtf8().data()).toHex());
+	free(old);
+}
+
+void learnImage(const QByteArray filename)
+{
+	MainWindow::instance()->localFilenameOf[hashFile(filename.data())] = strdup(filename.data());
+}
+
+void learnImages(const QDir &dir, int maxdepth)
+{
+	QDir current(dir);
+	QList<QByteArray> files;
+	QStringList filters;
+
+	if (maxdepth) {
+		foreach (QString dirname, dir.entryList(QStringList(), QDir::NoDotAndDotDot | QDir::Dirs)) {
+			learnImages(QDir(dir.filePath(dirname)), maxdepth - 1);
+		}
+	}
+
+	foreach (QString format, QImageReader::supportedImageFormats()) {
+		filters.append(QString("*.").append(format));
+	}
+
+	foreach (QString file, dir.entryList(filters, QDir::Files)) {
+		files.append(dir.absoluteFilePath(file).toUtf8());
+	}
+
+	QtConcurrent::blockingMap(files, learnImage);
+}
diff --git a/qthelper.h b/qthelper.h
index 61e968c..3826efa 100644
--- a/qthelper.h
+++ b/qthelper.h
@@ -7,6 +7,7 @@
 #include "dive.h"
 #include "divelist.h"
 #include <QTranslator>
+#include <QDir>
 
 // global pointers for our translation
 extern QTranslator *qtTranslator, *ssrfTranslator;
@@ -16,4 +17,9 @@ bool gpsHasChanged(struct dive *dive, struct dive *master, const QString &gps_te
 extern "C" const char *printGPSCoords(int lat, int lon);
 QList<int> getDivesInTrip(dive_trip_t *trip);
 QString gasToStr(struct gasmix gas);
+void read_hashes();
+void write_hashes();
+void updateHash(struct picture *picture);
+QByteArray hashFile(const char *filename);
+void learnImages(const QDir &dir, int maxdepth);
 #endif // QTHELPER_H
-- 
1.9.3 (Apple Git-50)