Clang plugin: Support for Blink in web/.

tools/clang/plugins/ChromeClassTester.cpp

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // A general interface for filtering and only acting on classes in Chromium C++
 // code.
 
 #include "ChromeClassTester.h"
 
 #include <algorithm>
@@ skipping 139 matching lines @@
     size_needed = WideCharToMultiByte(CP_UTF8, 0, full_utf16.data(), -1,
                                       nullptr, 0, nullptr, nullptr);
     filename.resize(size_needed);
     WideCharToMultiByte(CP_UTF8, 0, full_utf16.data(), -1, &filename[0],
                         size_needed, nullptr, nullptr);
   }
 
   std::replace(filename.begin(), filename.end(), '\\', '/');
 #endif
 
+  if (options_.check_for_blink)

[dcheng, 2017/04/17 02:40:57]

Hmm, so the potential issue with this is that Blink files include other
third_party code--and we want those SourceLocations to still be treated as
kThirdParty. Otherwise, this could cause the style checker plugin to warn on
third-party code if a Blink file includes a header from third_party.

I've been thinking about it more, and I have two main ideas to fix this:
- Use a namespace check to determine if something should be Blink or not. e.g.
namespace blink == Blink, otherwise something else
- Specify "web/public", "web/Source" as the blink directory paths.

I kind of prefer using "namespace blink" as the main check if possible, though
that's a bit clunky to implement atm. I think once
https://chromium-review.googlesource.com/c/478907/ land, this should be pretty
easy to do though. WDYT?

[tkent, 2017/04/17 08:00:23]

Ah, I see.
Patch Set 5 implemented this.
We'd like to omit "Source/". So, this would be "web/public, web/bindings,
web/core, web/devtools, web/modules, web/platform, web/web, or web/wtf".  It
wouldn't be robust for Blink-internal structure changes.  I'd like to assume
it's the last fallback option.

+    return LocationType::kBlink;
+  // TODO(tkent): Remove blink_directories_. We specify "-Xclang
+  // -plugin-arg-find-bad-constructs -Xclang check-for-blink" in BUILD.gn
+  // instead.
   for (const std::string& blink_dir : blink_directories_) {
     // If any of the allowed directories occur as a component in filename,
     // this file is allowed.
     assert(blink_dir.front() == '/' && "Allowed dir must start with '/'");
     assert(blink_dir.back() == '/' && "Allowed dir must end with '/'");
 
     if (filename.find(blink_dir) != std::string::npos)
       return LocationType::kBlink;
   }
 
@@ skipping 164 matching lines @@
   }
 
   *filename = ploc.getFilename();
   return true;
 }
 
 DiagnosticsEngine::Level ChromeClassTester::getErrorLevel() {
   return diagnostic().getWarningsAsErrors() ? DiagnosticsEngine::Error
                                             : DiagnosticsEngine::Warning;
 }