clang-format: Initial (incomplete) support for the WebKit coding style.

This is far from implementing all the rules given by
http://www.webkit.org/coding/coding-style.html

The important new feature is the support for styles that don't have a
column limit. For such styles, clang-format will (at the moment) simply
respect the input's formatting decisions within statements.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@187033 91177308-0d34-0410-b5e6-96231b3b80d8

include/clang/Format/Format.h

@@ -31,6 +31,10 @@ namespace format {
 /// specific guidelines.
 struct FormatStyle {
   /// \brief The column limit.
+  ///
+  /// A column limit of \c 0 means that there is no column limit. In this case,
+  /// clang-format will respect the input's line breaking decisions within
+  /// statements.
   unsigned ColumnLimit;
 
   /// \brief The maximum number of consecutive empty lines to keep.
@@ -218,6 +222,10 @@ FormatStyle getChromiumStyle();
 /// https://developer.mozilla.org/en-US/docs/Developer_Guide/Coding_Style.
 FormatStyle getMozillaStyle();
 
+/// \brief Returns a format style complying with Webkit's style guide:
+/// http://www.webkit.org/coding/coding-style.html
+FormatStyle getWebKitStyle();
+
 /// \brief Gets a predefined style by name.
 ///
 /// Currently supported names: LLVM, Google, Chromium, Mozilla. Names are

lib/Format/Format.cpp

@@ -219,6 +219,15 @@ FormatStyle getMozillaStyle() {
   return MozillaStyle;
 }
 
+FormatStyle getWebKitStyle() {
+  FormatStyle Style = getLLVMStyle();
+  Style.ColumnLimit = 0;
+  Style.IndentWidth = 4;
+  Style.BreakBeforeBraces = FormatStyle::BS_Stroustrup;
+  Style.PointerBindsToType = true;
+  return Style;
+}
+
 bool getPredefinedStyle(StringRef Name, FormatStyle *Style) {
   if (Name.equals_lower("llvm"))
     *Style = getLLVMStyle();
@@ -228,6 +237,8 @@ bool getPredefinedStyle(StringRef Name, FormatStyle *Style) {
     *Style = getMozillaStyle();
   else if (Name.equals_lower("google"))
     *Style = getGoogleStyle();
+  else if (Name.equals_lower("webkit"))
+    *Style = getWebKitStyle();
   else
     return false;
 
@@ -299,6 +310,11 @@ public:
     // The first token has already been indented and thus consumed.
     moveStateToNextToken(State, /*DryRun=*/false, /*Newline=*/false);
 
+    if (Style.ColumnLimit == 0) {
+      formatWithoutColumnLimit(State);
+      return;
+    }
+
     // If everything fits on a single line, just put it there.
     unsigned ColumnLimit = Style.ColumnLimit;
     if (NextLine && NextLine->InPPDirective &&
@@ -506,6 +522,15 @@ private:
     }
   };
 
+  /// \brief Formats the line starting at \p State, simply keeping all of the
+  /// input's line breaking decisions.
+  void formatWithoutColumnLimit(LineState &State) {
+    while (State.NextToken != NULL) {
+      bool Newline = State.NextToken->NewlinesBefore > 0;
+      addTokenToState(Newline, /*DryRun=*/false, State);
+    }
+  }
+
   /// \brief Appends the next token to \p State and updates information
   /// necessary for indentation.
   ///
@@ -1592,6 +1617,9 @@ private:
     if (I->Last->Type == TT_LineComment)
       return;
 
+    if (Indent > Style.ColumnLimit)
+      return;
+
     unsigned Limit = Style.ColumnLimit - Indent;
     // If we already exceed the column limit, we set 'Limit' to 0. The different
     // tryMerge..() functions can then decide whether to still do merging.

unittests/Format/FormatTest.cpp

@@ -5361,6 +5361,11 @@ TEST_F(FormatTest, GetsPredefinedStyleByName) {
   EXPECT_TRUE(getPredefinedStyle("moZILla", &Styles[2]));
   EXPECT_TRUE(allStylesEqual(Styles));
 
+  Styles[0] = getWebKitStyle();
+  EXPECT_TRUE(getPredefinedStyle("WebKit", &Styles[1]));
+  EXPECT_TRUE(getPredefinedStyle("wEbKit", &Styles[2]));
+  EXPECT_TRUE(allStylesEqual(Styles));
+
   EXPECT_FALSE(getPredefinedStyle("qwerty", &Styles[0]));
 }
 
@@ -5515,6 +5520,79 @@ TEST_F(FormatTest, SplitsUTF8BlockComments) {
             format("/* 𝓣𝓮𝓼𝓽 𝔣𝔬𝔲𝔯 𝕓𝕪𝕥𝕖 𝖀𝕿𝕱-𝟠 */", getLLVMStyleWithColumns(12)));
 }
 
+TEST_F(FormatTest, FormatsWithWebKitStyle) {
+  FormatStyle Style = getWebKitStyle();
+
+  // Don't indent in outer namespaces.
+  verifyFormat("namespace outer {\n"
+               "int i;\n"
+               "namespace inner {\n"
+               "int i;\n" // FIXME: This should be indented.
+               "} // namespace inner\n"
+               "} // namespace outer\n"
+               "namespace other_outer {\n"
+               "int i;\n"
+               "}",
+               Style);
+
+  // Don't indent case labels.
+  verifyFormat("switch (variable) {\n"
+               "case 1:\n"
+               "case 2:\n"
+               "    doSomething();\n"
+               "    break;\n"
+               "default:\n"
+               "    ++variable;\n"
+               "}",
+               Style);
+
+  // Wrap before binary operators.
+  EXPECT_EQ(
+      "void f()\n"
+      "{\n"
+      "    if (aaaaaaaaaaaaaaaa\n"
+      "        && bbbbbbbbbbbbbbbbbbbbbbbb\n"
+      "        && (cccccccccccccccccccccccccc || dddddddddddddddddddd))\n"
+      "        return;\n"
+      "}",
+      format(
+          "void f() {\n"
+          "if (aaaaaaaaaaaaaaaa\n"
+          "&& bbbbbbbbbbbbbbbbbbbbbbbb\n"
+          "&& (cccccccccccccccccccccccccc || dddddddddddddddddddd))\n"
+          "return;\n"
+          "}",
+          Style));
+
+  // Constructor initializers are formatted one per line with the "," on the
+  // new line.
+  // FIXME: This needs to be implemented.
+  // verifyFormat("Constructor()\n"
+  //              "    : aaaaaaaaaaaaaaaaaaaaaaaa(aaaaaaaaaaaaaaaaaaaaaaaaaaa)\n"
+  //              "    , aaaaaaaaaaaaaaaaaaaaaaaa(aaaaaaaaaaaaaaaaaaaaaaaaaaa,\n"
+  //              "                               aaaaaaaaaaaaaaaaaaaaaaaaaaa)\n"
+  //              "    , aaaaaaaaaaaaaaaaaaaaaaa() {}",
+  //              Style);
+
+  // Do not align comments.
+  // FIXME: Implement option to suppress comment alignment.
+  // verifyFormat("int a; // Do not\n"
+  //              "double b; // align comments.");
+
+  // Accept input's line breaks.
+  EXPECT_EQ("if (aaaaaaaaaaaaaaa\n"
+            "    || bbbbbbbbbbbbbbb) {\n"
+            "    i++;\n"
+            "}",
+            format("if (aaaaaaaaaaaaaaa\n"
+                   "|| bbbbbbbbbbbbbbb) { i++; }",
+                   Style));
+  EXPECT_EQ("if (aaaaaaaaaaaaaaa || bbbbbbbbbbbbbbb) {\n"
+            "    i++;\n"
+            "}",
+            format("if (aaaaaaaaaaaaaaa || bbbbbbbbbbbbbbb) { i++; }", Style));
+}
+
 #endif
 
 } // end namespace tooling