C++: support smart splitting of strings.

If 'enter' is pressed while the cursor is in the middle of a string,
the string is ended at the current cursor position, and a new string
is started on the next line.  This makes it very easy to split a long
string onto multiple lines.

In addition, Shift+Enter insert an escape in the string, to continue the
string at the beginning of next line.

A setting can be used to enable or disable this option.

Change-Id: Ia5f3c6989fc00d40d06bc4fe1182fe8b1318f565
Reviewed-by: Francois Ferrand <thetypz@gmail.com>
Reviewed-by: hjk <hjk121@nokiamail.com>

src/plugins/cppeditor/cppautocompleter.cpp

@@ -85,6 +85,37 @@ static bool isInCommentHelper(const QTextCursor &cursor, Token *retToken = 0)
     return tk.isComment();
 }
 
+static bool isInStringHelper(const QTextCursor &cursor, Token *retToken = 0)
+{
+    LanguageFeatures features;
+    features.qtEnabled = false;
+    features.qtKeywordsEnabled = false;
+    features.qtMocRunEnabled = false;
+    features.cxx11Enabled = true;
+    features.c99Enabled = true;
+
+    SimpleLexer tokenize;
+    tokenize.setLanguageFeatures(features);
+
+    const int prevState = BackwardsScanner::previousBlockState(cursor.block()) & 0xFF;
+    const QList<Token> tokens = tokenize(cursor.block().text(), prevState);
+
+    const unsigned pos = cursor.selectionEnd() - cursor.block().position();
+
+    if (tokens.isEmpty() || pos < tokens.first().utf16charsBegin())
+        return prevState > 0;
+
+    if (pos >= tokens.last().utf16charsEnd()) {
+        const Token tk = tokens.last();
+        return tk.isStringLiteral() && prevState > 0;
+    }
+
+    Token tk = tokenAtPosition(tokens, pos);
+    if (retToken)
+        *retToken = tk;
+    return tk.isStringLiteral();
+}
+
 bool CppAutoCompleter::contextAllowsAutoParentheses(const QTextCursor &cursor,
                                                     const QString &textToInsert) const
 {
@@ -124,6 +155,11 @@ bool CppAutoCompleter::isInComment(const QTextCursor &cursor) const
     return isInCommentHelper(cursor);
 }
 
+bool CppAutoCompleter::isInString(const QTextCursor &cursor) const
+{
+    return isInStringHelper(cursor);
+}
+
 QString CppAutoCompleter::insertMatchingBrace(const QTextCursor &cursor,
                                                 const QString &text,
                                                 QChar la,

src/plugins/cppeditor/cppautocompleter.h

@@ -45,6 +45,7 @@ public:
                                               const QString &textToInsert = QString()) const;
     virtual bool contextAllowsElectricCharacters(const QTextCursor &cursor) const;
     virtual bool isInComment(const QTextCursor &cursor) const;
+    virtual bool isInString(const QTextCursor &cursor) const;
     virtual QString insertMatchingBrace(const QTextCursor &cursor,
                                         const QString &text,
                                         QChar la,

src/plugins/cppeditor/cppeditor.cpp

@@ -59,8 +59,10 @@
 #include <cpptools/cppworkingcopy.h>
 #include <cpptools/symbolfinder.h>
 
+#include <texteditor/completionsettings.h>
 #include <texteditor/textdocument.h>
 #include <texteditor/textdocumentlayout.h>
+#include <texteditor/texteditorsettings.h>
 #include <texteditor/codeassist/assistproposalitem.h>
 #include <texteditor/codeassist/genericproposalmodel.h>
 #include <texteditor/codeassist/genericproposal.h>
@@ -536,12 +538,47 @@ void CppEditorWidget::keyPressEvent(QKeyEvent *e)
     if (d->m_localRenaming.handleKeyPressEvent(e))
         return;
 
+    if (handleStringSplitting(e))
+        return;
+
     if (d->m_cppDocumentationCommentHelper.handleKeyPressEvent(e))
         return;
 
     TextEditorWidget::keyPressEvent(e);
 }
 
+bool CppEditorWidget::handleStringSplitting(QKeyEvent *e) const
+{
+    if (!TextEditorSettings::completionSettings().m_autoSplitStrings)
+        return false;
+
+    if (e->key() == Qt::Key_Return || e->key() == Qt::Key_Enter) {
+        QTextCursor cursor = textCursor();
+
+        if (autoCompleter()->isInString(cursor)) {
+            cursor.beginEditBlock();
+            if (cursor.positionInBlock() > 0
+                    && cursor.block().text().at(cursor.positionInBlock() - 1) == QLatin1Char('\\')) {
+                // Already escaped: simply go back to line, but do not indent.
+                cursor.insertText(QLatin1String("\n"));
+            } else if (e->modifiers() & Qt::ShiftModifier) {
+                // With 'shift' modifier, escape the end of line character
+                // and start at beginning of next line.
+                cursor.insertText(QLatin1String("\\\n"));
+            } else {
+                // End the current string, and start a new one on the line, properly indented.
+                cursor.insertText(QLatin1String("\"\n\""));
+                textDocument()->autoIndent(cursor);
+            }
+            cursor.endEditBlock();
+            e->accept();
+            return true;
+        }
+    }
+
+    return false;
+}
+
 void CppEditorWidget::applyFontSettings()
 {
     // This also makes the document apply font settings

src/plugins/cppeditor/cppeditor.h

@@ -101,6 +101,7 @@ protected:
     bool event(QEvent *e) Q_DECL_OVERRIDE;
     void contextMenuEvent(QContextMenuEvent *) Q_DECL_OVERRIDE;
     void keyPressEvent(QKeyEvent *e) Q_DECL_OVERRIDE;
+    bool handleStringSplitting(QKeyEvent *e) const;
 
     void applyFontSettings() Q_DECL_OVERRIDE;
 

src/plugins/cpptools/completionsettingspage.cpp

@@ -99,6 +99,7 @@ QWidget *CompletionSettingsPage::widget()
         m_page->surroundSelectedText->setChecked(settings.m_surroundingAutoBrackets);
         m_page->partiallyComplete->setChecked(settings.m_partiallyComplete);
         m_page->spaceAfterFunctionName->setChecked(settings.m_spaceAfterFunctionName);
+        m_page->autoSplitStrings->setChecked(settings.m_autoSplitStrings);
         m_page->enableDoxygenCheckBox->setChecked(m_commentsSettings.m_enableDoxygen);
         m_page->generateBriefCheckBox->setChecked(m_commentsSettings.m_generateBrief);
         m_page->leadingAsterisksCheckBox->setChecked(m_commentsSettings.m_leadingAsterisks);
@@ -118,6 +119,7 @@ void CompletionSettingsPage::apply()
     settings.m_surroundingAutoBrackets = m_page->surroundSelectedText->isChecked();
     settings.m_partiallyComplete = m_page->partiallyComplete->isChecked();
     settings.m_spaceAfterFunctionName = m_page->spaceAfterFunctionName->isChecked();
+    settings.m_autoSplitStrings = m_page->autoSplitStrings->isChecked();
 
     TextEditor::TextEditorSettings::setCompletionSettings(settings);
 

src/plugins/cpptools/completionsettingspage.ui

@@ -17,6 +17,72 @@
       <string>Behavior</string>
      </property>
      <layout class="QGridLayout" name="gridLayout">
+      <item row="4" column="0">
+       <layout class="QHBoxLayout" name="horizontalLayout">
+        <item>
+         <spacer name="horizontalSpacer_2">
+          <property name="orientation">
+           <enum>Qt::Horizontal</enum>
+          </property>
+          <property name="sizeType">
+           <enum>QSizePolicy::Fixed</enum>
+          </property>
+          <property name="sizeHint" stdset="0">
+           <size>
+            <width>30</width>
+            <height>20</height>
+           </size>
+          </property>
+         </spacer>
+        </item>
+        <item>
+         <widget class="QCheckBox" name="surroundSelectedText">
+          <property name="toolTip">
+           <string>When typing a matching character and there is a text selection, instead of removing the selection, surrounds it with the corresponding characters.</string>
+          </property>
+          <property name="text">
+           <string>Surround &amp;text selections</string>
+          </property>
+          <property name="checked">
+           <bool>true</bool>
+          </property>
+         </widget>
+        </item>
+       </layout>
+      </item>
+      <item row="0" column="2" colspan="2">
+       <spacer name="horizontalSpacer">
+        <property name="orientation">
+         <enum>Qt::Horizontal</enum>
+        </property>
+        <property name="sizeHint" stdset="0">
+         <size>
+          <width>70</width>
+          <height>24</height>
+         </size>
+        </property>
+       </spacer>
+      </item>
+      <item row="1" column="0">
+       <widget class="QLabel" name="completionTriggerLabel">
+        <property name="text">
+         <string>Activate completion:</string>
+        </property>
+       </widget>
+      </item>
+      <item row="1" column="3">
+       <spacer name="horizontalSpacer_3">
+        <property name="orientation">
+         <enum>Qt::Horizontal</enum>
+        </property>
+        <property name="sizeHint" stdset="0">
+         <size>
+          <width>40</width>
+          <height>24</height>
+         </size>
+        </property>
+       </spacer>
+      </item>
       <item row="0" column="0">
        <widget class="QLabel" name="caseSensitivityLabel">
         <property name="text">
@@ -52,23 +118,10 @@
         </item>
        </widget>
       </item>
-      <item row="0" column="2" colspan="2">
-       <spacer name="horizontalSpacer">
-        <property name="orientation">
-         <enum>Qt::Horizontal</enum>
-        </property>
-        <property name="sizeHint" stdset="0">
-         <size>
-          <width>70</width>
-          <height>24</height>
-         </size>
-        </property>
-       </spacer>
-      </item>
-      <item row="1" column="0">
-       <widget class="QLabel" name="completionTriggerLabel">
+      <item row="6" column="0">
+       <widget class="QCheckBox" name="autoSplitStrings">
         <property name="text">
-         <string>Activate completion:</string>
+         <string>Automatically split strings</string>
         </property>
        </widget>
       </item>
@@ -91,19 +144,6 @@
         </item>
        </widget>
       </item>
-      <item row="1" column="3">
-       <spacer name="horizontalSpacer_3">
-        <property name="orientation">
-         <enum>Qt::Horizontal</enum>
-        </property>
-        <property name="sizeHint" stdset="0">
-         <size>
-          <width>40</width>
-          <height>24</height>
-         </size>
-        </property>
-       </spacer>
-      </item>
       <item row="2" column="0">
        <widget class="QCheckBox" name="partiallyComplete">
         <property name="toolTip">
@@ -130,40 +170,7 @@
         </property>
        </widget>
       </item>
-      <item row="4" column="0">
-       <layout class="QHBoxLayout" name="horizontalLayout">
-        <item>
-         <spacer name="horizontalSpacer_2">
-          <property name="orientation">
-           <enum>Qt::Horizontal</enum>
-          </property>
-          <property name="sizeType">
-           <enum>QSizePolicy::Fixed</enum>
-          </property>
-          <property name="sizeHint" stdset="0">
-           <size>
-            <width>30</width>
-            <height>20</height>
-           </size>
-          </property>
-         </spacer>
-        </item>
-        <item>
-         <widget class="QCheckBox" name="surroundSelectedText">
-          <property name="toolTip">
-           <string>When typing a matching character and there is a text selection, instead of removing the selection, surrounds it with the corresponding characters.</string>
-          </property>
-          <property name="text">
-           <string>Surround &amp;text selections</string>
-          </property>
-          <property name="checked">
-           <bool>true</bool>
-          </property>
-         </widget>
-        </item>
-       </layout>
-      </item>
-      <item row="5" column="0" colspan="2">
+      <item row="5" column="0">
        <layout class="QHBoxLayout" name="horizontalLayout_2">
         <item>
          <spacer name="horizontalSpacer_4">

src/plugins/texteditor/autocompleter.cpp

@@ -332,6 +332,12 @@ bool AutoCompleter::isInComment(const QTextCursor &cursor) const
     return false;
 }
 
+bool AutoCompleter::isInString(const QTextCursor &cursor) const
+{
+    Q_UNUSED(cursor);
+    return false;
+}
+
 QString AutoCompleter::insertMatchingBrace(const QTextCursor &cursor,
                                            const QString &text,
                                            QChar la,

src/plugins/texteditor/autocompleter.h

@@ -72,6 +72,9 @@ public:
     // Returns true if the cursor is inside a comment.
     virtual bool isInComment(const QTextCursor &cursor) const;
 
+    // Returns true if the cursor is inside a string.
+    virtual bool isInString(const QTextCursor &cursor) const;
+
     virtual QString insertMatchingBrace(const QTextCursor &cursor, const
                                         QString &text,
                                         QChar la,

src/plugins/texteditor/completionsettings.cpp

@@ -39,6 +39,7 @@ static const char autoInsertBracesKey[] = "AutoInsertBraces";
 static const char surroundingAutoBracketsKey[] = "SurroundingAutoBrackets";
 static const char partiallyCompleteKey[] = "PartiallyComplete";
 static const char spaceAfterFunctionNameKey[] = "SpaceAfterFunctionName";
+static const char autoSplitStringsKey[] = "AutoSplitStrings";
 
 using namespace TextEditor;
 
@@ -49,6 +50,7 @@ CompletionSettings::CompletionSettings()
     , m_surroundingAutoBrackets(true)
     , m_partiallyComplete(true)
     , m_spaceAfterFunctionName(false)
+    , m_autoSplitStrings(true)
 {
 }
 
@@ -65,6 +67,7 @@ void CompletionSettings::toSettings(const QString &category, QSettings *s) const
     s->setValue(QLatin1String(surroundingAutoBracketsKey), m_surroundingAutoBrackets);
     s->setValue(QLatin1String(partiallyCompleteKey), m_partiallyComplete);
     s->setValue(QLatin1String(spaceAfterFunctionNameKey), m_spaceAfterFunctionName);
+    s->setValue(QLatin1String(autoSplitStringsKey), m_autoSplitStrings);
     s->endGroup();
 }
 
@@ -83,6 +86,7 @@ void CompletionSettings::fromSettings(const QString &category, const QSettings *
     m_surroundingAutoBrackets = s->value(group + QLatin1String(surroundingAutoBracketsKey), m_surroundingAutoBrackets).toBool();
     m_partiallyComplete = s->value(group + QLatin1String(partiallyCompleteKey), m_partiallyComplete).toBool();
     m_spaceAfterFunctionName = s->value(group + QLatin1String(spaceAfterFunctionNameKey), m_spaceAfterFunctionName).toBool();
+    m_autoSplitStrings = s->value(group + QLatin1String(autoSplitStringsKey), m_autoSplitStrings).toBool();
 }
 
 bool CompletionSettings::equals(const CompletionSettings &cs) const
@@ -93,5 +97,6 @@ bool CompletionSettings::equals(const CompletionSettings &cs) const
         && m_surroundingAutoBrackets == cs.m_surroundingAutoBrackets
         && m_partiallyComplete == cs.m_partiallyComplete
         && m_spaceAfterFunctionName == cs.m_spaceAfterFunctionName
+        && m_autoSplitStrings == cs.m_autoSplitStrings
         ;
 }

src/plugins/texteditor/completionsettings.h

@@ -70,6 +70,7 @@ public:
     bool m_surroundingAutoBrackets;
     bool m_partiallyComplete;
     bool m_spaceAfterFunctionName;
+    bool m_autoSplitStrings;
 };
 
 inline bool operator==(const CompletionSettings &t1, const CompletionSettings &t2) { return t1.equals(t2); }