Do not use libcurl for reading local files

We originally used libcurl for both downloading images from
Internet and reading local files to have the same code path for both.

It doesn't work that well in practice, as Qt and libcurl are not
on the same page how special characters such as Chinese characters
are represented in a local file URL.

So create a new class to handle local files.

Closes #76

CMakeLists.txt

@@ -20,7 +20,7 @@ set(CMAKE_AUTORCC ON)
 
 # Adding headers explicity so they are displayed in Qt Creator
 set(HEADERS config.h imagewriter.h networkaccessmanagerfactory.h nan.h drivelistitem.h drivelistmodel.h driveformatthread.h powersaveblocker.h
-    downloadthread.h downloadextractthread.h dependencies/mountutils/src/mountutils.hpp)
+    downloadthread.h downloadextractthread.h localfileextractthread.h dependencies/mountutils/src/mountutils.hpp)
 
 # Add dependencies
 if (APPLE)
@@ -68,7 +68,7 @@ endif()
 
 set(SOURCES "main.cpp" "imagewriter.cpp" "networkaccessmanagerfactory.cpp"
     "drivelistitem.cpp" "drivelistmodel.cpp" "downloadthread.cpp" "downloadextractthread.cpp"
-     "driveformatthread.cpp" "powersaveblocker.cpp" "qml.qrc")
+     "driveformatthread.cpp" "localfileextractthread.cpp" "powersaveblocker.cpp" "qml.qrc")
 
 find_package(Qt5 COMPONENTS Core Quick LinguistTools Svg OPTIONAL_COMPONENTS Widgets)
 if (Qt5Widgets_FOUND)

downloadextractthread.cpp

@@ -382,12 +382,12 @@ int DownloadExtractThread::_on_close(struct archive *)
 // static callback functions that call object oriented equivalents
 ssize_t DownloadExtractThread::_archive_read(struct archive *a, void *client_data, const void **buff)
 {
-   return static_cast<DownloadExtractThread *>(client_data)->_on_read(a, buff);
+   return qobject_cast<DownloadExtractThread *>((QObject *) client_data)->_on_read(a, buff);
 }
 
 int DownloadExtractThread::_archive_close(struct archive *a, void *client_data)
 {
-   return static_cast<DownloadExtractThread *>(client_data)->_on_close(a);
+   return qobject_cast<DownloadExtractThread *>((QObject *) client_data)->_on_close(a);
 }
 
 bool DownloadExtractThread::isImage()

downloadextractthread.h

@@ -48,13 +48,13 @@ protected:
 
     QByteArray _popQueue();
     void _pushQueue(const char *data, size_t len);
-    void _cancelExtract();
+    virtual void _cancelExtract();
     virtual size_t _writeData(const char *buf, size_t len);
     virtual void _onDownloadSuccess();
     virtual void _onDownloadError(const QString &msg);
 
-    ssize_t _on_read(struct archive *a, const void **buff);
-    int _on_close(struct archive *a);
+    virtual ssize_t _on_read(struct archive *a, const void **buff);
+    virtual int _on_close(struct archive *a);
 
     static ssize_t _archive_read(struct archive *a, void *client_data, const void **buff);
     static int _archive_close(struct archive *a, void *client_data);

imagewriter.cpp

@@ -8,6 +8,7 @@
 #include "downloadextractthread.h"
 #include "dependencies/drivelist/src/drivelist.hpp"
 #include "driveformatthread.h"
+#include "localfileextractthread.h"
 #include <archive.h>
 #include <archive_entry.h>
 #include <QFileInfo>
@@ -182,7 +183,11 @@ void ImageWriter::startWrite()
         urlstr = QUrl::fromLocalFile(_cacheFileName).toString(_src.FullyEncoded).toLatin1();
     }
 
-    if (compressed)
+    if (QUrl(urlstr).isLocalFile())
+    {
+        _thread = new LocalFileExtractThread(urlstr, _dst.toLatin1(), _expectedHash, this);
+    }
+    else if (compressed)
     {
         _thread = new DownloadExtractThread(urlstr, _dst.toLatin1(), _expectedHash, this);
     }

localfileextractthread.cpp

@@ -0,0 +1,74 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ * Copyright (C) 2020 Raspberry Pi (Trading) Limited
+ */
+
+#include "localfileextractthread.h"
+#include "config.h"
+
+LocalFileExtractThread::LocalFileExtractThread(const QByteArray &url, const QByteArray &dst, const QByteArray &expectedHash, QObject *parent)
+    : DownloadExtractThread(url, dst, expectedHash, parent)
+{
+    _inputBuf = (char *) qMallocAligned(IMAGEWRITER_UNCOMPRESSED_BLOCKSIZE, 4096);
+}
+
+LocalFileExtractThread::~LocalFileExtractThread()
+{
+    _cancelled = true;
+    wait();
+    qFreeAligned(_inputBuf);
+}
+
+void LocalFileExtractThread::_cancelExtract()
+{
+    _cancelled = true;
+    if (_inputfile.isOpen())
+        _inputfile.close();
+}
+
+void LocalFileExtractThread::run()
+{
+    if (isImage() && !_openAndPrepareDevice())
+        return;
+
+    _timer.start();
+    _inputfile.setFileName( QUrl(_url).toLocalFile() );
+    if (!_inputfile.open(_inputfile.ReadOnly))
+    {
+        _onDownloadError(tr("Error opening image file"));
+        return;
+    }
+    _lastDlTotal = _inputfile.size();
+
+    if (isImage())
+        extractImageRun();
+    else
+        extractMultiFileRun();
+
+}
+
+ssize_t LocalFileExtractThread::_on_read(struct archive *, const void **buff)
+{
+    if (_cancelled)
+        return -1;
+
+    *buff = _inputBuf;
+    ssize_t len = _inputfile.read(_inputBuf, IMAGEWRITER_UNCOMPRESSED_BLOCKSIZE);
+
+    if (len > 0)
+    {
+        _lastDlNow += len;
+        if (!_isImage)
+        {
+            _inputHash.addData(_inputBuf, len);
+        }
+    }
+
+    return len;
+}
+
+int LocalFileExtractThread::_on_close(struct archive *)
+{
+    _inputfile.close();
+    return 0;
+}

localfileextractthread.h

@@ -0,0 +1,28 @@
+#ifndef LOCALFILEEXTRACTTHREAD_H
+#define LOCALFILEEXTRACTTHREAD_H
+
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ * Copyright (C) 2020 Raspberry Pi (Trading) Limited
+ */
+
+#include "downloadextractthread.h"
+#include <QFile>
+
+class LocalFileExtractThread : public DownloadExtractThread
+{
+    Q_OBJECT
+public:
+    explicit LocalFileExtractThread(const QByteArray &url, const QByteArray &dst = "", const QByteArray &expectedHash = "", QObject *parent = nullptr);
+    virtual ~LocalFileExtractThread();
+
+protected:
+    virtual void _cancelExtract();
+    virtual void run();
+    virtual ssize_t _on_read(struct archive *a, const void **buff);
+    virtual int _on_close(struct archive *a);
+    QFile _inputfile;
+    char *_inputBuf;
+};
+
+#endif // LOCALFILEEXTRACTTHREAD_H