Config file support for clang-format, part 2.

Summary:
Adds actual config file reading to the clang-format utility.
Configuration file name is .clang-format. It is looked up for each input file
in its parent directories starting from immediate one. First found .clang-format
file is used. When using standard input, .clang-format is searched starting from
the current directory.
Added -dump-config option to easily create configuration files.

Reviewers: djasper, klimek

Reviewed By: klimek

CC: cfe-commits, jordan_rose, kimgr

Differential Revision: http://llvm-reviews.chandlerc.com/D758

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@181589 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 50 insertions, 14 deletions

diff --git a/tools/clang-format/ClangFormat.cpp b/tools/clang-format/ClangFormat.cpp
index 57833edf0f..5ae95781fb 100644
--- a/tools/clang-format/ClangFormat.cpp
+++ b/tools/clang-format/ClangFormat.cpp
@@ -20,6 +20,7 @@
 #include "clang/Format/Format.h"
 #include "clang/Lex/Lexer.h"
 #include "clang/Rewrite/Core/Rewriter.h"
+#include "llvm/Support/Debug.h"
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/Signals.h"
 
@@ -36,13 +37,20 @@ Lengths("length", cl::desc("Format a range of this length. "
                            "Can only be used with one input file."));
 static cl::opt<std::string> Style(
     "style",
-    cl::desc("Coding style, currently supports: LLVM, Google, Chromium, Mozilla."),
+    cl::desc(
+        "Coding style, currently supports: LLVM, Google, Chromium, Mozilla. "
+        "Use '-style file' to load style configuration from .clang-format file "
+        "located in one of the parent directories of the source file (or "
+        "current directory for stdin)."),
     cl::init("LLVM"));
 static cl::opt<bool> Inplace("i",
                              cl::desc("Inplace edit <file>s, if specified."));
 
 static cl::opt<bool> OutputXML(
     "output-replacements-xml", cl::desc("Output replacements as XML."));
+static cl::opt<bool>
+    DumpConfig("dump-config",
+               cl::desc("Dump configuration options to stdout and exit. Can be used with -style option."));
 
 static cl::list<std::string> FileNames(cl::Positional,
                                        cl::desc("[<file> ...]"));
@@ -59,18 +67,38 @@ static FileID createInMemoryFile(StringRef FileName, const MemoryBuffer *Source,
   return Sources.createFileID(Entry, SourceLocation(), SrcMgr::C_User);
 }
 
-static FormatStyle getStyle() {
-  FormatStyle TheStyle = getGoogleStyle();
-  if (Style == "LLVM")
-    TheStyle = getLLVMStyle();
-  else if (Style == "Chromium")
-    TheStyle = getChromiumStyle();
-  else if (Style == "Mozilla")
-    TheStyle = getMozillaStyle();
-  else if (Style != "Google")
-    llvm::errs() << "Unknown style " << Style << ", using Google style.\n";
-
-  return TheStyle;
+FormatStyle getStyle(StringRef StyleName, StringRef FileName) {
+  if (!StyleName.equals_lower("file"))
+    return getPredefinedStyle(StyleName);
+
+  SmallString<128> Path(FileName);
+  llvm::sys::fs::make_absolute(Path);
+  for (StringRef Directory = llvm::sys::path::parent_path(Path);
+       !Directory.empty();
+       Directory = llvm::sys::path::parent_path(Directory)) {
+    SmallString<128> ConfigFile(Directory);
+    llvm::sys::path::append(ConfigFile, ".clang-format");
+    DEBUG(llvm::dbgs() << "Trying " << ConfigFile << "...\n");
+    bool IsFile = false;
+    llvm::sys::fs::is_regular_file(Twine(ConfigFile), IsFile);
+    if (IsFile) {
+      OwningPtr<MemoryBuffer> Text;
+      if (error_code ec = MemoryBuffer::getFile(ConfigFile, Text)) {
+        llvm::errs() << ec.message() << "\n";
+        continue;
+      }
+      FormatStyle Style;
+      if (error_code ec = parseConfiguration(Text->getBuffer(), &Style)) {
+        llvm::errs() << "Error reading " << ConfigFile << ": " << ec.message()
+                     << "\n";
+        continue;
+      }
+      DEBUG(llvm::dbgs() << "Using configuration file " << ConfigFile << "\n");
+      return Style;
+    }
+  }
+  llvm::errs() << "Can't find usable .clang-format, using LLVM style\n";
+  return getLLVMStyle();
 }
 
 // Returns true on error.
@@ -118,7 +146,8 @@ static bool format(std::string FileName) {
     }
     Ranges.push_back(CharSourceRange::getCharRange(Start, End));
   }
-  tooling::Replacements Replaces = reformat(getStyle(), Lex, Sources, Ranges);
+  tooling::Replacements Replaces =
+      reformat(getStyle(Style, FileName), Lex, Sources, Ranges);
   if (OutputXML) {
     llvm::outs()
         << "<?xml version='1.0'?>\n<replacements xml:space='preserve'>\n";
@@ -171,6 +200,13 @@ int main(int argc, const char **argv) {
   if (Help)
     cl::PrintHelpMessage();
 
+  if (DumpConfig) {
+    std::string Config = clang::format::configurationAsText(
+        clang::format::getStyle(Style, FileNames.empty() ? "-" : FileNames[0]));
+    llvm::outs() << Config << "\n";
+    return 0;
+  }
+
   bool Error = false;
   switch (FileNames.size()) {
   case 0: