Support configurable trailing-whitespace cleanup

Allow the user to configure how trailing whitespace is handled. In some
file types, for example, Markdown, trailing whitespace is semantically
important. This change allows the user to select, via delimited list of
wildcard filename patterns, which files to ignore for trailing
whitespace cleanup.

Task-number: QTCREATORBUG-13358
Change-Id: Ie6814d8c178bed8e3de78e6d359b9940d2ba0ead
Reviewed-by: David Schulz <david.schulz@qt.io>

1 files changed, 49 insertions, 3 deletions

diff --git a/src/plugins/texteditor/storagesettings.cpp b/src/plugins/texteditor/storagesettings.cpp
index a1c4645b0c..2053ffa440 100644
--- a/src/plugins/texteditor/storagesettings.cpp
+++ b/src/plugins/texteditor/storagesettings.cpp
@@ -27,6 +27,7 @@
 
 #include <utils/settingsutils.h>
 
+#include <QRegularExpression>
 #include <QSettings>
 #include <QString>
 
@@ -36,13 +37,18 @@ static const char cleanWhitespaceKey[] = "cleanWhitespace";
 static const char inEntireDocumentKey[] = "inEntireDocument";
 static const char addFinalNewLineKey[] = "addFinalNewLine";
 static const char cleanIndentationKey[] = "cleanIndentation";
+static const char skipTrailingWhitespaceKey[] = "skipTrailingWhitespace";
+static const char ignoreFileTypesKey[] = "ignoreFileTypes";
 static const char groupPostfix[] = "StorageSettings";
+static const char defaultTrailingWhitespaceBlacklist[] = "*.md, *.MD, Makefile";
 
 StorageSettings::StorageSettings()
-    : m_cleanWhitespace(true),
+    : m_ignoreFileTypes(defaultTrailingWhitespaceBlacklist),
+      m_cleanWhitespace(true),
       m_inEntireDocument(false),
       m_addFinalNewLine(true),
-      m_cleanIndentation(true)
+      m_cleanIndentation(true),
+      m_skipTrailingWhitespace(true)
 {
 }
 
@@ -63,6 +69,8 @@ void StorageSettings::toMap(const QString &prefix, QVariantMap *map) const
     map->insert(prefix + QLatin1String(inEntireDocumentKey), m_inEntireDocument);
     map->insert(prefix + QLatin1String(addFinalNewLineKey), m_addFinalNewLine);
     map->insert(prefix + QLatin1String(cleanIndentationKey), m_cleanIndentation);
+    map->insert(prefix + QLatin1String(skipTrailingWhitespaceKey), m_skipTrailingWhitespace);
+    map->insert(prefix + QLatin1String(ignoreFileTypesKey), m_ignoreFileTypes.toLatin1().data());
 }
 
 void StorageSettings::fromMap(const QString &prefix, const QVariantMap &map)
@@ -75,6 +83,42 @@ void StorageSettings::fromMap(const QString &prefix, const QVariantMap &map)
         map.value(prefix + QLatin1String(addFinalNewLineKey), m_addFinalNewLine).toBool();
     m_cleanIndentation =
         map.value(prefix + QLatin1String(cleanIndentationKey), m_cleanIndentation).toBool();
+    m_skipTrailingWhitespace =
+        map.value(prefix + QLatin1String(skipTrailingWhitespaceKey), m_skipTrailingWhitespace).toBool();
+    m_ignoreFileTypes =
+        map.value(prefix + QLatin1String(ignoreFileTypesKey), m_ignoreFileTypes).toString();
+}
+
+bool StorageSettings::removeTrailingWhitespace(const QString &fileName) const
+{
+    // if the user has elected not to trim trailing whitespace altogether, then
+    // early out here
+    if (!m_skipTrailingWhitespace) {
+        return true;
+    }
+
+    const QString ignoreFileTypesRegExp(R"(\s*((?>\*\.)?[\w\d\.\*]+)[,;]?\s*)");
+
+    // use the ignore-files regex to extract the specified file patterns
+    QRegularExpression re(ignoreFileTypesRegExp);
+    QRegularExpressionMatchIterator iter = re.globalMatch(m_ignoreFileTypes);
+
+    while (iter.hasNext()) {
+        QRegularExpressionMatch match = iter.next();
+        QString pattern = match.captured(1);
+
+        QString wildcardRegExp = QRegularExpression::wildcardToRegularExpression(pattern);
+        QRegularExpression patternRegExp(wildcardRegExp);
+        QRegularExpressionMatch patternMatch = patternRegExp.match(fileName);
+        if (patternMatch.hasMatch()) {
+            // if the filename has a pattern we want to ignore, then we need to return
+            // false ("don't remove trailing whitespace")
+            return false;
+        }
+    }
+
+    // the supplied pattern does not match, so we want to remove trailing whitespace
+    return true;
 }
 
 bool StorageSettings::equals(const StorageSettings &ts) const
@@ -82,7 +126,9 @@ bool StorageSettings::equals(const StorageSettings &ts) const
     return m_addFinalNewLine == ts.m_addFinalNewLine
         && m_cleanWhitespace == ts.m_cleanWhitespace
         && m_inEntireDocument == ts.m_inEntireDocument
-        && m_cleanIndentation == ts.m_cleanIndentation;
+        && m_cleanIndentation == ts.m_cleanIndentation
+        && m_skipTrailingWhitespace == ts.m_skipTrailingWhitespace
+        && m_ignoreFileTypes == ts.m_ignoreFileTypes;
 }
 
 } // namespace TextEditor