clang-format 2014-12-03 (new formula)

clang-format is a versatile source code formatter, part of the clang
(and thus llvm) project. It can be used for C++, ObjC, Java, and
JavaScript.

The build is using cmake and ninja for speed; building all of llvm or
using configure and make is very slow.

clang-format is released in roughly monthly testing pushes, tracked by
the subversion tags in "google/testing/yyyy-MM-dd". This formula uses
tarballs from github that correspond to the resolved tags.

Closes #35777.

Signed-off-by: Mike McQuaid <mike@mikemcquaid.com>

Library/Formula/clang-format.rb

@@ -0,0 +1,47 @@
+class ClangFormat < Formula
+  homepage "http://clang.llvm.org/docs/ClangFormat.html"
+  version "2014-12-03"
+
+  stable do
+    url "http://llvm.org/svn/llvm-project/llvm/tags/google/testing/2014-12-03/", :using => :svn
+
+    resource "clang" do
+      url "http://llvm.org/svn/llvm-project/cfe/tags/google/testing/2014-12-03/", :using => :svn
+    end
+
+    resource "libcxx" do
+      url "http://llvm.org/releases/3.5.0/libcxx-3.5.0.src.tar.xz"
+      sha1 "c98beed86ae1adf9ab7132aeae8fd3b0893ea995"
+    end
+  end
+
+  depends_on "cmake" => :build
+  depends_on "ninja" => :build
+  depends_on "subversion" => :build
+
+  fails_with :clang do
+    build 503
+    cause "Host Clang must be able to find libstdc++4.7 or newer!"
+  end
+
+  def install
+    (buildpath/"projects/libcxx").install resource("libcxx")
+    (buildpath/"tools/clang").install resource("clang")
+
+    mkdir "build" do
+      system "cmake", "..", "-G", "Ninja", *std_cmake_args
+      system "ninja", "clang-format"
+      bin.install "bin/clang-format"
+    end
+  end
+
+  test do
+    # NB: below C code is messily formatted on purpose.
+    (testpath/"test.c").write <<-EOS
+      int         main(char *args) { \n   \t printf("hello"); }
+    EOS
+
+    assert_equal "int main(char *args) { printf(\"hello\"); }\n",
+        shell_output("#{bin}/clang-format -style=Google test.c")
+  end
+end