//===- AbseilMatcher.h - clang-tidy ---------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

#include "clang/AST/ASTContext.h"
#include "clang/ASTMatchers/ASTMatchFinder.h"
#include <algorithm>

namespace clang::ast_matchers {

/// Matches AST nodes that were found within Abseil files.
///
/// Example matches Y but not X
///     (matcher = cxxRecordDecl(isInAbseilFile())
/// \code
///   #include "absl/strings/internal-file.h"
///   class X {};
/// \endcode
/// absl/strings/internal-file.h:
/// \code
///   class Y {};
/// \endcode
///
/// Usable as: Matcher<Decl>, Matcher<Stmt>, Matcher<TypeLoc>,
/// Matcher<NestedNameSpecifierLoc>
AST_POLYMORPHIC_MATCHER(
    isInAbseilFile, AST_POLYMORPHIC_SUPPORTED_TYPES(Decl, Stmt, TypeLoc,
                                                    NestedNameSpecifierLoc)) {
  auto &SourceManager = Finder->getASTContext().getSourceManager();
  SourceLocation Loc = SourceManager.getSpellingLoc(Node.getBeginLoc());
  if (Loc.isInvalid())
    return false;
  OptionalFileEntryRef FileEntry =
      SourceManager.getFileEntryRefForID(SourceManager.getFileID(Loc));
  if (!FileEntry)
    return false;
  // Determine whether filepath contains "absl/[absl-library]" substring, where
  // [absl-library] is AbseilLibraries list entry.
  StringRef Path = FileEntry->getName();
  static constexpr llvm::StringLiteral AbslPrefix("absl/");
  size_t PrefixPosition = Path.find(AbslPrefix);
  if (PrefixPosition == StringRef::npos)
    return false;
  Path = Path.drop_front(PrefixPosition + AbslPrefix.size());
  static constexpr llvm::StringLiteral AbseilLibraries[] = {
      "algorithm", "base",     "container", "debugging", "flags",
      "hash",      "iterator", "memory",    "meta",      "numeric",
      "profiling", "random",   "status",    "strings",   "synchronization",
      "time",      "types",    "utility"};
  return llvm::any_of(AbseilLibraries, [&](llvm::StringLiteral Library) {
    return Path.starts_with(Library);
  });
}

} // namespace clang::ast_matchers
