//===--- tools/extra/clang-tidy/ClangTidyMain.cpp - Clang tidy tool -------===//
//
// 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
//
//===----------------------------------------------------------------------===//
///
///  \file This file implements a clang-tidy tool.
///
///  This tool uses the Clang Tooling infrastructure, see
///    http://clang.llvm.org/docs/HowToSetupToolingForLLVM.html
///  for details on setting it up with LLVM source tree.
///
//===----------------------------------------------------------------------===//

#include "../ClangTidy.h"
#include "../ClangTidyForceLinker.h"
#include "../GlobList.h"
#include "clang/Tooling/CommonOptionsParser.h"
#include "llvm/Support/Process.h"
#include "llvm/Support/Signals.h"
#include "llvm/Support/TargetSelect.h"

using namespace clang::ast_matchers;
using namespace clang::driver;
using namespace clang::tooling;
using namespace llvm;

static cl::OptionCategory ClangTidyCategory("clang-tidy options");

static cl::extrahelp CommonHelp(CommonOptionsParser::HelpMessage);
static cl::extrahelp ClangTidyHelp(R"(
Configuration files:
  clang-tidy attempts to read configuration for each source file from a
  .clang-tidy file located in the closest parent directory of the source
  file. If any configuration options have a corresponding command-line
  option, command-line option takes precedence. The effective
  configuration can be inspected using -dump-config:

    $ clang-tidy -dump-config
    ---
    Checks:          '-*,some-check'
    WarningsAsErrors: ''
    HeaderFilterRegex: ''
    FormatStyle:     none
    User:            user
    CheckOptions:
      - key:             some-check.SomeOption
        value:           'some value'
    ...

)");

const char DefaultChecks[] = // Enable these checks by default:
    "clang-diagnostic-*,"    //   * compiler diagnostics
    "clang-analyzer-*";      //   * Static Analyzer checks

static cl::opt<std::string> Checks("checks", cl::desc(R"(
Comma-separated list of globs with optional '-'
prefix. Globs are processed in order of
appearance in the list. Globs without '-'
prefix add checks with matching names to the
set, globs with the '-' prefix remove checks
with matching names from the set of enabled
checks. This option's value is appended to the
value of the 'Checks' option in .clang-tidy
file, if any.
)"),
                                   cl::init(""), cl::cat(ClangTidyCategory));

static cl::opt<std::string> WarningsAsErrors("warnings-as-errors", cl::desc(R"(
Upgrades warnings to errors. Same format as
'-checks'.
This option's value is appended to the value of
the 'WarningsAsErrors' option in .clang-tidy
file, if any.
)"),
                                             cl::init(""),
                                             cl::cat(ClangTidyCategory));

static cl::opt<std::string> HeaderFilter("header-filter", cl::desc(R"(
Regular expression matching the names of the
headers to output diagnostics from. Diagnostics
from the main file of each translation unit are
always displayed.
Can be used together with -line-filter.
This option overrides the 'HeaderFilterRegex'
option in .clang-tidy file, if any.
)"),
                                         cl::init(""),
                                         cl::cat(ClangTidyCategory));

static cl::opt<bool>
    SystemHeaders("system-headers",
                  cl::desc("Display the errors from system headers."),
                  cl::init(false), cl::cat(ClangTidyCategory));
static cl::opt<std::string> LineFilter("line-filter", cl::desc(R"(
List of files with line ranges to filter the
warnings. Can be used together with
-header-filter. The format of the list is a
JSON array of objects:
  [
    {"name":"file1.cpp","lines":[[1,3],[5,7]]},
    {"name":"file2.h"}
  ]
)"),
                                       cl::init(""),
                                       cl::cat(ClangTidyCategory));

static cl::opt<bool> Fix("fix", cl::desc(R"(
Apply suggested fixes. Without -fix-errors
clang-tidy will bail out if any compilation
errors were found.
)"),
                         cl::init(false), cl::cat(ClangTidyCategory));

static cl::opt<bool> FixErrors("fix-errors", cl::desc(R"(
Apply suggested fixes even if compilation
errors were found. If compiler errors have
attached fix-its, clang-tidy will apply them as
well.
)"),
                               cl::init(false), cl::cat(ClangTidyCategory));

static cl::opt<std::string> FormatStyle("format-style", cl::desc(R"(
Style for formatting code around applied fixes:
  - 'none' (default) turns off formatting
  - 'file' (literally 'file', not a placeholder)
    uses .clang-format file in the closest parent
    directory
  - '{ <json> }' specifies options inline, e.g.
    -format-style='{BasedOnStyle: llvm, IndentWidth: 8}'
  - 'llvm', 'google', 'webkit', 'mozilla'
See clang-format documentation for the up-to-date
information about formatting styles and options.
This option overrides the 'FormatStyle` option in
.clang-tidy file, if any.
)"),
                                   cl::init("none"),
                                   cl::cat(ClangTidyCategory));

static cl::opt<bool> ListChecks("list-checks", cl::desc(R"(
List all enabled checks and exit. Use with
-checks=* to list all available checks.
)"),
                                cl::init(false), cl::cat(ClangTidyCategory));

static cl::opt<bool> ExplainConfig("explain-config", cl::desc(R"(
For each enabled check explains, where it is
enabled, i.e. in clang-tidy binary, command
line or a specific configuration file.
)"),
                                   cl::init(false), cl::cat(ClangTidyCategory));

static cl::opt<std::string> Config("config", cl::desc(R"(
Specifies a configuration in YAML/JSON format:
  -config="{Checks: '*',
            CheckOptions: [{key: x,
                            value: y}]}"
When the value is empty, clang-tidy will
attempt to find a file named .clang-tidy for
each source file in its parent directories.
)"),
                                   cl::init(""), cl::cat(ClangTidyCategory));

static cl::opt<bool> DumpConfig("dump-config", cl::desc(R"(
Dumps configuration in the YAML format to
stdout. This option can be used along with a
file name (and '--' if the file is outside of a
project with configured compilation database).
The configuration used for this file will be
printed.
Use along with -checks=* to include
configuration of all checks.
)"),
                                cl::init(false), cl::cat(ClangTidyCategory));

static cl::opt<bool> EnableCheckProfile("enable-check-profile", cl::desc(R"(
Enable per-check timing profiles, and print a
report to stderr.
)"),
                                        cl::init(false),
                                        cl::cat(ClangTidyCategory));

static cl::opt<std::string> StoreCheckProfile("store-check-profile",
                                              cl::desc(R"(
By default reports are printed in tabulated
format to stderr. When this option is passed,
these per-TU profiles are instead stored as JSON.
)"),
                                              cl::value_desc("prefix"),
                                              cl::cat(ClangTidyCategory));

/// This option allows enabling the experimental alpha checkers from the static
/// analyzer. This option is set to false and not visible in help, because it is
/// highly not recommended for users.
static cl::opt<bool>
    AllowEnablingAnalyzerAlphaCheckers("allow-enabling-analyzer-alpha-checkers",
                                       cl::init(false), cl::Hidden,
                                       cl::cat(ClangTidyCategory));

static cl::opt<std::string> ExportFixes("export-fixes", cl::desc(R"(
YAML file to store suggested fixes in. The
stored fixes can be applied to the input source
code with clang-apply-replacements.
)"),
                                        cl::value_desc("filename"),
                                        cl::cat(ClangTidyCategory));

static cl::opt<bool> Quiet("quiet", cl::desc(R"(
Run clang-tidy in quiet mode. This suppresses
printing statistics about ignored warnings and
warnings treated as errors if the respective
options are specified.
)"),
                           cl::init(false),
                           cl::cat(ClangTidyCategory));

static cl::opt<std::string> VfsOverlay("vfsoverlay", cl::desc(R"(
Overlay the virtual filesystem described by file
over the real file system.
)"),
                                       cl::value_desc("filename"),
                                       cl::cat(ClangTidyCategory));

namespace clang {
namespace tidy {

static void printStats(const ClangTidyStats &Stats) {
  if (Stats.errorsIgnored()) {
    llvm::errs() << "Suppressed " << Stats.errorsIgnored() << " warnings (";
    StringRef Separator = "";
    if (Stats.ErrorsIgnoredNonUserCode) {
      llvm::errs() << Stats.ErrorsIgnoredNonUserCode << " in non-user code";
      Separator = ", ";
    }
    if (Stats.ErrorsIgnoredLineFilter) {
      llvm::errs() << Separator << Stats.ErrorsIgnoredLineFilter
                   << " due to line filter";
      Separator = ", ";
    }
    if (Stats.ErrorsIgnoredNOLINT) {
      llvm::errs() << Separator << Stats.ErrorsIgnoredNOLINT << " NOLINT";
      Separator = ", ";
    }
    if (Stats.ErrorsIgnoredCheckFilter)
      llvm::errs() << Separator << Stats.ErrorsIgnoredCheckFilter
                   << " with check filters";
    llvm::errs() << ").\n";
    if (Stats.ErrorsIgnoredNonUserCode)
      llvm::errs() << "Use -header-filter=.* to display errors from all "
                      "non-system headers. Use -system-headers to display "
                      "errors from system headers as well.\n";
  }
}

static std::unique_ptr<ClangTidyOptionsProvider> createOptionsProvider(
   llvm::IntrusiveRefCntPtr<vfs::FileSystem> FS) {
  ClangTidyGlobalOptions GlobalOptions;
  if (std::error_code Err = parseLineFilter(LineFilter, GlobalOptions)) {
    llvm::errs() << "Invalid LineFilter: " << Err.message() << "\n\nUsage:\n";
    llvm::cl::PrintHelpMessage(/*Hidden=*/false, /*Categorized=*/true);
    return nullptr;
  }

  ClangTidyOptions DefaultOptions;
  DefaultOptions.Checks = DefaultChecks;
  DefaultOptions.WarningsAsErrors = "";
  DefaultOptions.HeaderFilterRegex = HeaderFilter;
  DefaultOptions.SystemHeaders = SystemHeaders;
  DefaultOptions.FormatStyle = FormatStyle;
  DefaultOptions.User = llvm::sys::Process::GetEnv("USER");
  // USERNAME is used on Windows.
  if (!DefaultOptions.User)
    DefaultOptions.User = llvm::sys::Process::GetEnv("USERNAME");

  ClangTidyOptions OverrideOptions;
  if (Checks.getNumOccurrences() > 0)
    OverrideOptions.Checks = Checks;
  if (WarningsAsErrors.getNumOccurrences() > 0)
    OverrideOptions.WarningsAsErrors = WarningsAsErrors;
  if (HeaderFilter.getNumOccurrences() > 0)
    OverrideOptions.HeaderFilterRegex = HeaderFilter;
  if (SystemHeaders.getNumOccurrences() > 0)
    OverrideOptions.SystemHeaders = SystemHeaders;
  if (FormatStyle.getNumOccurrences() > 0)
    OverrideOptions.FormatStyle = FormatStyle;

  if (!Config.empty()) {
    if (llvm::ErrorOr<ClangTidyOptions> ParsedConfig =
            parseConfiguration(Config)) {
      return std::make_unique<ConfigOptionsProvider>(
          GlobalOptions,
          ClangTidyOptions::getDefaults().mergeWith(DefaultOptions),
          *ParsedConfig, OverrideOptions);
    } else {
      llvm::errs() << "Error: invalid configuration specified.\n"
                   << ParsedConfig.getError().message() << "\n";
      return nullptr;
    }
  }
  return std::make_unique<FileOptionsProvider>(GlobalOptions, DefaultOptions,
                                                OverrideOptions, std::move(FS));
}

llvm::IntrusiveRefCntPtr<vfs::FileSystem>
getVfsFromFile(const std::string &OverlayFile,
               llvm::IntrusiveRefCntPtr<vfs::FileSystem> BaseFS) {
  llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>> Buffer =
      BaseFS->getBufferForFile(OverlayFile);
  if (!Buffer) {
    llvm::errs() << "Can't load virtual filesystem overlay file '"
                 << OverlayFile << "': " << Buffer.getError().message()
                 << ".\n";
    return nullptr;
  }

  IntrusiveRefCntPtr<vfs::FileSystem> FS = vfs::getVFSFromYAML(
      std::move(Buffer.get()), /*DiagHandler*/ nullptr, OverlayFile);
  if (!FS) {
    llvm::errs() << "Error: invalid virtual filesystem overlay file '"
                 << OverlayFile << "'.\n";
    return nullptr;
  }
  return FS;
}

static int clangTidyMain(int argc, const char **argv) {
  llvm::sys::PrintStackTraceOnErrorSignal(argv[0]);
  CommonOptionsParser OptionsParser(argc, argv, ClangTidyCategory,
                                    cl::ZeroOrMore);
  llvm::IntrusiveRefCntPtr<vfs::OverlayFileSystem> BaseFS(
      new vfs::OverlayFileSystem(vfs::getRealFileSystem()));

  if (!VfsOverlay.empty()) {
    IntrusiveRefCntPtr<vfs::FileSystem> VfsFromFile =
        getVfsFromFile(VfsOverlay, BaseFS);
    if (!VfsFromFile)
      return 1;
    BaseFS->pushOverlay(VfsFromFile);
  }

  auto OwningOptionsProvider = createOptionsProvider(BaseFS);
  auto *OptionsProvider = OwningOptionsProvider.get();
  if (!OptionsProvider)
    return 1;

  auto MakeAbsolute = [](const std::string &Input) -> SmallString<256> {
    if (Input.empty())
      return {};
    SmallString<256> AbsolutePath(Input);
    if (std::error_code EC = llvm::sys::fs::make_absolute(AbsolutePath)) {
      llvm::errs() << "Can't make absolute path from " << Input << ": "
                   << EC.message() << "\n";
    }
    return AbsolutePath;
  };

  SmallString<256> ProfilePrefix = MakeAbsolute(StoreCheckProfile);

  StringRef FileName("dummy");
  auto PathList = OptionsParser.getSourcePathList();
  if (!PathList.empty()) {
    FileName = PathList.front();
  }

  SmallString<256> FilePath = MakeAbsolute(FileName);

  ClangTidyOptions EffectiveOptions = OptionsProvider->getOptions(FilePath);
  std::vector<std::string> EnabledChecks =
      getCheckNames(EffectiveOptions, AllowEnablingAnalyzerAlphaCheckers);

  if (ExplainConfig) {
    // FIXME: Show other ClangTidyOptions' fields, like ExtraArg.
    std::vector<clang::tidy::ClangTidyOptionsProvider::OptionsSource>
        RawOptions = OptionsProvider->getRawOptions(FilePath);
    for (const std::string &Check : EnabledChecks) {
      for (auto It = RawOptions.rbegin(); It != RawOptions.rend(); ++It) {
        if (It->first.Checks && GlobList(*It->first.Checks).contains(Check)) {
          llvm::outs() << "'" << Check << "' is enabled in the " << It->second
                       << ".\n";
          break;
        }
      }
    }
    return 0;
  }

  if (ListChecks) {
    if (EnabledChecks.empty()) {
      llvm::errs() << "No checks enabled.\n";
      return 1;
    }
    llvm::outs() << "Enabled checks:";
    for (const auto &CheckName : EnabledChecks)
      llvm::outs() << "\n    " << CheckName;
    llvm::outs() << "\n\n";
    return 0;
  }

  if (DumpConfig) {
    EffectiveOptions.CheckOptions =
        getCheckOptions(EffectiveOptions, AllowEnablingAnalyzerAlphaCheckers);
    llvm::outs() << configurationAsText(
                        ClangTidyOptions::getDefaults().mergeWith(
                            EffectiveOptions))
                 << "\n";
    return 0;
  }

  if (EnabledChecks.empty()) {
    llvm::errs() << "Error: no checks enabled.\n";
    llvm::cl::PrintHelpMessage(/*Hidden=*/false, /*Categorized=*/true);
    return 1;
  }

  if (PathList.empty()) {
    llvm::errs() << "Error: no input files specified.\n";
    llvm::cl::PrintHelpMessage(/*Hidden=*/false, /*Categorized=*/true);
    return 1;
  }

  llvm::InitializeAllTargetInfos();
  llvm::InitializeAllTargetMCs();
  llvm::InitializeAllAsmParsers();

  ClangTidyContext Context(std::move(OwningOptionsProvider),
                           AllowEnablingAnalyzerAlphaCheckers);
  std::vector<ClangTidyError> Errors =
      runClangTidy(Context, OptionsParser.getCompilations(), PathList, BaseFS,
                   EnableCheckProfile, ProfilePrefix);
  bool FoundErrors = llvm::find_if(Errors, [](const ClangTidyError &E) {
                       return E.DiagLevel == ClangTidyError::Error;
                     }) != Errors.end();

  const bool DisableFixes = Fix && FoundErrors && !FixErrors;

  unsigned WErrorCount = 0;

  // -fix-errors implies -fix.
  handleErrors(Errors, Context, (FixErrors || Fix) && !DisableFixes, WErrorCount,
               BaseFS);

  if (!ExportFixes.empty() && !Errors.empty()) {
    std::error_code EC;
    llvm::raw_fd_ostream OS(ExportFixes, EC, llvm::sys::fs::OF_None);
    if (EC) {
      llvm::errs() << "Error opening output file: " << EC.message() << '\n';
      return 1;
    }
    exportReplacements(FilePath.str(), Errors, OS);
  }

  if (!Quiet) {
    printStats(Context.getStats());
    if (DisableFixes)
      llvm::errs()
          << "Found compiler errors, but -fix-errors was not specified.\n"
             "Fixes have NOT been applied.\n\n";
  }

  if (WErrorCount) {
    if (!Quiet) {
      StringRef Plural = WErrorCount == 1 ? "" : "s";
      llvm::errs() << WErrorCount << " warning" << Plural << " treated as error"
                   << Plural << "\n";
    }
    return WErrorCount;
  }

  if (FoundErrors) {
    // TODO: Figure out when zero exit code should be used with -fix-errors:
    //   a. when a fix has been applied for an error
    //   b. when a fix has been applied for all errors
    //   c. some other condition.
    // For now always returning zero when -fix-errors is used.
    if (FixErrors)
      return 0;
    if (!Quiet)
      llvm::errs() << "Found compiler error(s).\n";
    return 1;
  }

  return 0;
}

} // namespace tidy
} // namespace clang

int main(int argc, const char **argv) {
  return clang::tidy::clangTidyMain(argc, argv);
}