// Copyright (c) 2011 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 <sys/param.h>

#include "clang/Basic/FileManager.h"

using namespace clang;

namespace {

bool starts_with(const std::string& one, const std::string& two) {
  return one.compare(0, two.size(), two) == 0;
}

bool ends_with(const std::string& one, const std::string& two) {
  if (two.size() > one.size())
    return false;

  return one.compare(one.size() - two.size(), two.size(), two) == 0;
}

}  // namespace

ChromeClassTester::ChromeClassTester(CompilerInstance& instance)
    : instance_(instance),
      diagnostic_(instance.getDiagnostics()) {
  FigureOutSrcRoot();
  BuildBannedLists();
}

void ChromeClassTester::FigureOutSrcRoot() {
  char c_cwd[MAXPATHLEN];
  if (getcwd(c_cwd, MAXPATHLEN) > 0) {
    size_t pos = 1;
    std::string cwd = c_cwd;

    // Add a trailing '/' because the search below requires it.
    if (cwd[cwd.size() - 1] != '/')
      cwd += '/';

    // Search the directory tree downwards until we find a path that contains
    // "build/common.gypi" and assume that that is our srcroot.
    size_t next_slash = cwd.find('/', pos);
    while (next_slash != std::string::npos) {
      next_slash++;
      std::string candidate = cwd.substr(0, next_slash);

      if (ends_with(candidate, "src/")) {
        std::string common = candidate + "build/common.gypi";
        if (access(common.c_str(), F_OK) != -1) {
          src_root_ = candidate;
          break;
        }
      }

      pos = next_slash;
      next_slash = cwd.find('/', pos);
    }
  }

  if (src_root_.empty()) {
    unsigned id = diagnostic().getCustomDiagID(
        Diagnostic::Error,
        "WARNING: Can't figure out srcroot!\n");
    diagnostic().Report(id);
  }
}

void ChromeClassTester::BuildBannedLists() {
  banned_namespaces_.push_back("std");
  banned_namespaces_.push_back("__gnu_cxx");

  banned_directories_.push_back("third_party");
  banned_directories_.push_back("native_client");
  banned_directories_.push_back("breakpad");
  banned_directories_.push_back("courgette");
  banned_directories_.push_back("ppapi");
  banned_directories_.push_back("testing");
  banned_directories_.push_back("googleurl");
  banned_directories_.push_back("v8");
  banned_directories_.push_back("sdch");

  // Don't check autogenerated headers.
  banned_directories_.push_back("out");
  banned_directories_.push_back("llvm");
  banned_directories_.push_back("ninja");
  banned_directories_.push_back("xcodebuild");
  banned_directories_.push_back("clang");

  // You are standing in a mazy of twisty dependencies, all resolved by
  // putting everything in the header.
  banned_directories_.push_back("chrome/test/automation");

  // Don't check system headers.
  banned_directories_.push_back("/usr");
  banned_directories_.push_back("/Developer");

  // Used in really low level threading code that probably shouldn't be out of
  // lined.
  ignored_record_names_.insert("ThreadLocalBoolean");

  // A complicated pickle derived struct that is all packed integers.
  ignored_record_names_.insert("Header");

  // Part of the GPU system that uses multiple included header
  // weirdness. Never getting this right.
  ignored_record_names_.insert("Validators");

  // RAII class that's simple enough (media/base/callback.h).
  ignored_record_names_.insert("AutoCallbackRunner");

  // Has a UNIT_TEST only constructor. Isn't *terribly* complex...
  ignored_record_names_.insert("AutocompleteController");
  ignored_record_names_.insert("HistoryURLProvider");

  // Because of chrome frame
  ignored_record_names_.insert("ReliabilityTestSuite");

  // Used over in the net unittests. A large enough bundle of integers with 1
  // non-pod class member. Probably harmless.
  ignored_record_names_.insert("MockTransaction");

  // Used heavily in app_unittests and once in views_unittests. Fixing this
  // isn't worth the overhead of an additional library.
  ignored_record_names_.insert("TestAnimationDelegate");

  // Part of our public interface that nacl and friends use. (Arguably, this
  // should mean that this is a higher priority but fixing this looks hard.)
  ignored_record_names_.insert("PluginVersionInfo");
}

ChromeClassTester::~ChromeClassTester() {}

void ChromeClassTester::HandleTagDeclDefinition(TagDecl* tag) {
  // We handle class types here where we have semantic information. We can only
  // check structs/classes/enums here, but we get a bunch of nice semantic
  // information instead of just parsing information.

  if (CXXRecordDecl* record = dyn_cast<CXXRecordDecl>(tag)) {
    // If this is a POD or a class template or a type dependent on a
    // templated class, assume there's no ctor/dtor/virtual method
    // optimization that we can do.
    if (record->isPOD() ||
        record->getDescribedClassTemplate() ||
        record->getTemplateSpecializationKind() ||
        record->isDependentType())
      return;

    if (InBannedNamespace(record))
      return;

    SourceLocation record_location = record->getInnerLocStart();
    if (InBannedDirectory(record_location))
      return;

    // We sadly need to maintain a blacklist of types that violate these
    // rules, but do so for good reason or due to limitations of this
    // checker (i.e., we don't handle extern templates very well).
    std::string base_name = record->getNameAsString();
    if (IsIgnoredType(base_name))
      return;

    // We ignore all classes that end with "Matcher" because they're probably
    // GMock artifacts.
    if (ends_with(base_name, "Matcher"))
        return;

    CheckChromeClass(record_location, record);
  }
}

void ChromeClassTester::emitWarning(SourceLocation loc, const char* raw_error) {
  FullSourceLoc full(loc, instance().getSourceManager());
  std::string err;
  err = "[chromium-style] ";
  err += raw_error;
  Diagnostic::Level level =
      diagnostic().getWarningsAsErrors() ?
      Diagnostic::Error :
      Diagnostic::Warning;
  unsigned id = diagnostic().getCustomDiagID(level, err);
  DiagnosticBuilder B = diagnostic().Report(full, id);
}

bool ChromeClassTester::InTestingNamespace(Decl* record) {
  return GetNamespace(record).find("testing") != std::string::npos;
}

bool ChromeClassTester::InBannedNamespace(Decl* record) {
  std::string n = GetNamespace(record);
  if (n != "") {
    return std::find(banned_namespaces_.begin(), banned_namespaces_.end(), n)
        != banned_namespaces_.end();
  }

  return false;
}

std::string ChromeClassTester::GetNamespace(Decl* record) {
  return GetNamespaceImpl(record->getDeclContext(), "");
}

std::string ChromeClassTester::GetNamespaceImpl(const DeclContext* context,
                                                std::string candidate) {
  switch (context->getDeclKind()) {
    case Decl::TranslationUnit: {
      return candidate;
    }
    case Decl::Namespace: {
      const NamespaceDecl* decl = dyn_cast<NamespaceDecl>(context);
      std::string name_str;
      llvm::raw_string_ostream OS(name_str);
      if (decl->isAnonymousNamespace())
        OS << "<anonymous namespace>";
      else
        OS << decl;
      return GetNamespaceImpl(context->getParent(),
                              OS.str());
    }
    default: {
      return GetNamespaceImpl(context->getParent(), candidate);
    }
  }
}

bool ChromeClassTester::InBannedDirectory(SourceLocation loc) {
  const SourceManager &SM = instance_.getSourceManager();
  SourceLocation spelling_location = SM.getSpellingLoc(loc);
  PresumedLoc ploc = SM.getPresumedLoc(spelling_location);
  std::string buffer_name;
  if (ploc.isInvalid()) {
    // If we're in an invalid location, we're looking at things that aren't
    // actually stated in the source; treat this as a banned location instead
    // of going through our full lookup process.
    return true;
  } else {
    std::string b = ploc.getFilename();

    // We need to special case scratch space; which is where clang does its
    // macro expansion. We explicitly want to allow people to do otherwise bad
    // things through macros that were defined due to third party libraries.
    if (b == "<scratch space>")
      return true;

    // Don't complain about these things in implementation files.
    if (ends_with(b, ".cc") || ends_with(b, ".cpp") || ends_with(b, ".mm")) {
      return true;
    }

    // Don't complain about autogenerated protobuf files.
    if (ends_with(b, ".pb.h")) {
      return true;
    }

    // We need to munge the paths so that they are relative to the repository
    // srcroot. We first resolve the symlinktastic relative path and then
    // remove our known srcroot from it if needed.
    char resolvedPath[MAXPATHLEN];
    if (realpath(b.c_str(), resolvedPath)) {
      std::string resolved = resolvedPath;
      if (starts_with(resolved, src_root_)) {
        b = resolved.substr(src_root_.size());
      }
    }

    for (std::vector<std::string>::const_iterator it =
             banned_directories_.begin();
         it != banned_directories_.end(); ++it) {
      if (starts_with(b, *it)) {
        return true;
      }
    }
  }

  return false;
}

bool ChromeClassTester::IsIgnoredType(const std::string& base_name) {
  return ignored_record_names_.find(base_name) != ignored_record_names_.end();
}