fakevim: Added basic code folding

Implemented folding commands "za" (toggle fold), "zA", "zR" and "zM"
(toggle/open/close all folds recursively).

Other commands should work with folded blocks, e.g. dd on folded block
deletes whole block.

Folding a block moves cursor to the top of the block. Moving cursor left
or right or unfolding the block again won't restore the cursor position
as it was before folding (in Vim the position is restored).

Change-Id: I9fde30ea9358760419486e092d1032e85f415dc1
Reviewed-by: hjk <qthjk@ovi.com>

src/plugins/fakevim/fakevimplugin.cpp

@@ -843,6 +843,9 @@ private slots:
     void windowCommand(int key);
     void find(bool reverse);
     void findNext(bool reverse);
+    void foldToggle(int depth);
+    void foldAll(bool fold);
+    void fold(int depth, bool fold);
     void showSettingsDialog();
     void maybeReadVimRc();
     void setBlockSelection(bool);
@@ -1348,6 +1351,96 @@ void FakeVimPluginPrivate::findNext(bool reverse)
         triggerAction(Find::Constants::FIND_NEXT);
 }
 
+void FakeVimPluginPrivate::foldToggle(int depth)
+{
+    IEditor *ieditor = EditorManager::currentEditor();
+    BaseTextEditorWidget *editor = qobject_cast<BaseTextEditorWidget *>(ieditor->widget());
+    QTC_ASSERT(editor != 0, return);
+
+    QTextBlock block = editor->textCursor().block();
+    fold(depth, !BaseTextDocumentLayout::isFolded(block));
+}
+
+void FakeVimPluginPrivate::foldAll(bool fold)
+{
+    IEditor *ieditor = EditorManager::currentEditor();
+    BaseTextEditorWidget *editor = qobject_cast<BaseTextEditorWidget *>(ieditor->widget());
+    QTC_ASSERT(editor != 0, return);
+
+    QTextDocument *doc = editor->document();
+    BaseTextDocumentLayout *documentLayout =
+            qobject_cast<BaseTextDocumentLayout*>(doc->documentLayout());
+    QTC_ASSERT(documentLayout != 0, return);
+
+    QTextBlock block = editor->document()->firstBlock();
+    while (block.isValid()) {
+        BaseTextDocumentLayout::doFoldOrUnfold(block, !fold);
+        block = block.next();
+    }
+
+    documentLayout->requestUpdate();
+    documentLayout->emitDocumentSizeChanged();
+}
+
+void FakeVimPluginPrivate::fold(int depth, bool fold)
+{
+    IEditor *ieditor = EditorManager::currentEditor();
+    BaseTextEditorWidget *editor = qobject_cast<BaseTextEditorWidget *>(ieditor->widget());
+    QTC_ASSERT(editor != 0, return);
+
+    QTextDocument *doc = editor->document();
+    BaseTextDocumentLayout *documentLayout =
+            qobject_cast<BaseTextDocumentLayout*>(doc->documentLayout());
+    QTC_ASSERT(documentLayout != 0, return);
+
+    QTextBlock block = editor->textCursor().block();
+    int indent = BaseTextDocumentLayout::foldingIndent(block);
+    if (fold) {
+        if (BaseTextDocumentLayout::isFolded(block)) {
+            while (block.isValid() && (BaseTextDocumentLayout::foldingIndent(block) >= indent
+                || !block.isVisible())) {
+                block = block.previous();
+            }
+        }
+        if (BaseTextDocumentLayout::canFold(block))
+            ++indent;
+        while (depth != 0 && block.isValid()) {
+            const int indent2 = BaseTextDocumentLayout::foldingIndent(block);
+            if (BaseTextDocumentLayout::canFold(block) && indent2 < indent) {
+                BaseTextDocumentLayout::doFoldOrUnfold(block, false);
+                if (depth > 0)
+                    --depth;
+                indent = indent2;
+            }
+            block = block.previous();
+        }
+    } else {
+        if (BaseTextDocumentLayout::isFolded(block)) {
+            if (depth < 0) {
+                // recursively open fold
+                while (depth < 0 && block.isValid()
+                    && BaseTextDocumentLayout::foldingIndent(block) >= indent) {
+                    if (BaseTextDocumentLayout::canFold(block)) {
+                        BaseTextDocumentLayout::doFoldOrUnfold(block, true);
+                        if (depth > 0)
+                            --depth;
+                    }
+                    block = block.next();
+                }
+            } else {
+                if (BaseTextDocumentLayout::canFold(block)) {
+                    BaseTextDocumentLayout::doFoldOrUnfold(block, true);
+                    if (depth > 0)
+                        --depth;
+                }
+            }
+        }
+    }
+
+    documentLayout->requestUpdate();
+    documentLayout->emitDocumentSizeChanged();
+}
+
 // This class defers deletion of a child FakeVimHandler using deleteLater().
 class DeferredDeleter : public QObject
 {
@@ -1420,6 +1513,12 @@ void FakeVimPluginPrivate::editorOpened(IEditor *editor)
         SLOT(find(bool)));
     connect(handler, SIGNAL(findNextRequested(bool)),
         SLOT(findNext(bool)));
+    connect(handler, SIGNAL(foldToggle(int)),
+        SLOT(foldToggle(int)));
+    connect(handler, SIGNAL(foldAll(bool)),
+        SLOT(foldAll(bool)));
+    connect(handler, SIGNAL(fold(int,bool)),
+        SLOT(fold(int,bool)));
 
     connect(handler, SIGNAL(handleExCommandRequested(bool*,ExCommand)),
         SLOT(handleExCommand(bool*,ExCommand)));