DiffEditor: add info bar for documents with encoding errors

... with the option to reload the diff document with another encoding.

Fixes: QTCREATORBUG-23835
Change-Id: I1ce07b292688059b37535f2972970d8ea91be81b
Reviewed-by: hjk <hjk@qt.io>

src/plugins/diffeditor/diffeditorconstants.h

@@ -38,6 +38,7 @@ const char DIFF_EDITOR_MIMETYPE[] = "text/x-patch";
 const char C_DIFF_EDITOR_DESCRIPTION[] = "DiffEditor.Description";
 const char SIDE_BY_SIDE_VIEW_ID[] = "DiffEditor.SideBySide";
 const char UNIFIED_VIEW_ID[] = "DiffEditor.Unified";
+const char SELECT_ENCODING[] = "DiffEditor.SelectEncoding";
 
 const char G_TOOLS_DIFF[] = "QtCreator.Group.Tools.Options";
 

src/plugins/diffeditor/diffeditordocument.cpp

@@ -31,7 +31,9 @@
 #include <utils/fileutils.h>
 #include <utils/qtcassert.h>
 
+#include <coreplugin/dialogs/codecselector.h>
 #include <coreplugin/editormanager/editormanager.h>
+#include <coreplugin/icore.h>
 
 #include <QCoreApplication>
 #include <QFile>
@@ -314,10 +316,10 @@ Core::IDocument::OpenResult DiffEditorDocument::open(QString *errorString, const
     beginReload();
     QString patch;
     ReadResult readResult = read(fileName, &patch, errorString);
-    if (readResult == TextFileFormat::ReadEncodingError)
+    if (readResult == TextFileFormat::ReadIOError
-        return OpenResult::CannotHandle;
+        || readResult == TextFileFormat::ReadMemoryAllocationError) {
-    else if (readResult != TextFileFormat::ReadSuccess)
         return OpenResult::ReadError;
+    }
 
     bool ok = false;
     QList<FileData> fileDataList = DiffUtils::readPatch(patch, &ok);
@@ -333,9 +335,29 @@ Core::IDocument::OpenResult DiffEditorDocument::open(QString *errorString, const
         setDiffFiles(fileDataList, fi.absolutePath());
     }
     endReload(ok);
+    if (!ok && readResult == TextFileFormat::ReadEncodingError)
+        ok = selectEncoding();
     return ok ? OpenResult::Success : OpenResult::CannotHandle;
 }
 
+bool DiffEditorDocument::selectEncoding()
+{
+    Core::CodecSelector codecSelector(Core::ICore::dialogParent(), this);
+    switch (codecSelector.exec()) {
+    case Core::CodecSelector::Reload: {
+        setCodec(codecSelector.selectedCodec());
+        QString errorMessage;
+        return reload(&errorMessage, Core::IDocument::FlagReload, Core::IDocument::TypeContents);
+    }
+    case Core::CodecSelector::Save:
+        setCodec(codecSelector.selectedCodec());
+        return Core::EditorManager::saveDocument(this);
+    case Core::CodecSelector::Cancel:
+        break;
+    }
+    return false;
+}
+
 QString DiffEditorDocument::fallbackSaveAsFileName() const
 {
     const int maxSubjectLength = 50;

src/plugins/diffeditor/diffeditordocument.h

@@ -86,6 +86,7 @@ public:
     bool reload(QString *errorString, ReloadFlag flag, ChangeType type) override;
     OpenResult open(QString *errorString, const QString &fileName,
                     const QString &realFileName) override;
+    bool selectEncoding();
     State state() const { return m_state; }
 
     QString plainText() const;

src/plugins/diffeditor/diffeditorwidgetcontroller.cpp

@@ -30,6 +30,7 @@
 
 #include <coreplugin/documentmanager.h>
 #include <coreplugin/editormanager/editormanager.h>
+#include <coreplugin/infobar.h>
 #include <coreplugin/patchtool.h>
 
 #include <texteditor/fontsettings.h>
@@ -76,7 +77,7 @@ void DiffEditorWidgetController::setDocument(DiffEditorDocument *document)
 
     if (m_document) {
         disconnect(m_document, &IDocument::aboutToReload, this, &DiffEditorWidgetController::scheduleShowProgress);
-        disconnect(m_document, &IDocument::reloadFinished, this, &DiffEditorWidgetController::hideProgress);
+        disconnect(m_document, &IDocument::reloadFinished, this, &DiffEditorWidgetController::onDocumentReloadFinished);
     }
 
     const bool wasRunning = m_document && m_document->state() == DiffEditorDocument::Reloading;
@@ -85,7 +86,8 @@ void DiffEditorWidgetController::setDocument(DiffEditorDocument *document)
 
     if (m_document) {
         connect(m_document, &IDocument::aboutToReload, this, &DiffEditorWidgetController::scheduleShowProgress);
-        connect(m_document, &IDocument::reloadFinished, this, &DiffEditorWidgetController::hideProgress);
+        connect(m_document, &IDocument::reloadFinished, this, &DiffEditorWidgetController::onDocumentReloadFinished);
+        updateCannotDecodeInfo();
     }
 
     const bool isRunning = m_document && m_document->state() == DiffEditorDocument::Reloading;
@@ -123,6 +125,12 @@ void DiffEditorWidgetController::hideProgress()
         m_progressIndicator->hide();
 }
 
+void DiffEditorWidgetController::onDocumentReloadFinished()
+{
+    updateCannotDecodeInfo();
+    hideProgress();
+}
+
 void DiffEditorWidgetController::patch(bool revert, int fileIndex, int chunkIndex)
 {
     if (!m_document)
@@ -294,6 +302,27 @@ void DiffEditorWidgetController::addExtraActions(QMenu *menu, int fileIndex, int
         controller->requestChunkActions(menu, fileIndex, chunkIndex, selection);
 }
 
+void DiffEditorWidgetController::updateCannotDecodeInfo()
+{
+    if (!m_document)
+        return;
+
+    InfoBar *infoBar = m_document->infoBar();
+    Id selectEncodingId(Constants::SELECT_ENCODING);
+    if (m_document->hasDecodingError()) {
+        if (!infoBar->canInfoBeAdded(selectEncodingId))
+            return;
+        InfoBarEntry info(selectEncodingId,
+                          tr("<b>Error:</b> Could not decode \"%1\" with \"%2\"-encoding.")
+                              .arg(m_document->displayName(),
+                                   QString::fromLatin1(m_document->codec()->name())));
+        info.setCustomButtonInfo(tr("Select Encoding"), [this]() { m_document->selectEncoding(); });
+        infoBar->addInfo(info);
+    } else {
+        infoBar->removeInfo(selectEncodingId);
+    }
+}
+
 void DiffEditorWidgetController::sendChunkToCodePaster(int fileIndex, int chunkIndex)
 {
     if (!m_document)

src/plugins/diffeditor/diffeditorwidgetcontroller.h

@@ -61,6 +61,7 @@ public:
     void addApplyAction(QMenu *menu, int fileIndex, int chunkIndex);
     void addRevertAction(QMenu *menu, int fileIndex, int chunkIndex);
     void addExtraActions(QMenu *menu, int fileIndex, int chunkIndex, const ChunkSelection &selection);
+    void updateCannotDecodeInfo();
 
     ChunkData chunkData(int fileIndex, int chunkIndex) const;
 
@@ -83,6 +84,7 @@ private:
     void scheduleShowProgress();
     void showProgress();
     void hideProgress();
+    void onDocumentReloadFinished();
 
     QWidget *m_diffEditorWidget = nullptr;