//===- JSONCompilationDatabase.cpp ----------------------------------------===//

//

// 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

//

//===----------------------------------------------------------------------===//

//

//  This file contains the implementation of the JSONCompilationDatabase.

//

//===----------------------------------------------------------------------===//

#include "clang/Tooling/JSONCompilationDatabase.h"

#include "clang/Basic/LLVM.h"

#include "clang/Tooling/CompilationDatabase.h"

#include "clang/Tooling/CompilationDatabasePluginRegistry.h"

#include "clang/Tooling/Tooling.h"

#include "llvm/ADT/Optional.h"

#include "llvm/ADT/STLExtras.h"

#include "llvm/ADT/SmallString.h"

#include "llvm/ADT/SmallVector.h"

#include "llvm/ADT/StringRef.h"

#include "llvm/ADT/Triple.h"

#include "llvm/Support/Allocator.h"

#include "llvm/Support/Casting.h"

#include "llvm/Support/CommandLine.h"

#include "llvm/Support/ErrorOr.h"

#include "llvm/Support/Host.h"

#include "llvm/Support/MemoryBuffer.h"

#include "llvm/Support/Path.h"

#include "llvm/Support/StringSaver.h"

#include "llvm/Support/VirtualFileSystem.h"

#include "llvm/Support/YAMLParser.h"

#include "llvm/Support/raw_ostream.h"

#include <cassert>

#include <memory>

#include <string>

#include <system_error>

#include <tuple>

#include <utility>

#include <vector>

using namespace clang;

using namespace tooling;

namespace {

/// A parser for escaped strings of command line arguments.

///

/// Assumes \-escaping for quoted arguments (see the documentation of

/// unescapeCommandLine(...)).

class CommandLineArgumentParser {

 public:

  CommandLineArgumentParser(StringRef CommandLine)

      : Input(CommandLine), Position(Input.begin()-1) {}

  std::vector<std::string> parse() {

    bool HasMoreInput = true;

    while (HasMoreInput && 
nextNonWhitespace()700
) {

      std::string Argument;

      HasMoreInput = parseStringInto(Argument);

      CommandLine.push_back(Argument);

    }

    return CommandLine;

  }

 private:

  // All private methods return true if there is more input available.

  bool parseStringInto(std::string &String) {

    do {

      if (*Position == '"') {

        if (!parseDoubleQuotedStringInto(String)) 
return false8
;

      } else if (*Position == '\'') {

        if (!parseSingleQuotedStringInto(String)) return false;

      } else {

        if (!parseFreeStringInto(String)) 
return false114
;

      }

    } while (*Position != ' ');

    return true;

  }

  bool parseDoubleQuotedStringInto(std::string &String) {

    if (!next()) 
return false1
;

    
while (17
*Position != '"') {

      if (!skipEscapeCharacter()) 
return false0
;

      String.push_back(*Position);

      if (!next()) 
return false1
;

    }

    return next();

  }

  bool parseSingleQuotedStringInto(std::string &String) {

    if (!next()) 
return false0
;

    
while (1
*Position != '\'') {

      String.push_back(*Position);

      if (!next()) 
return false0
;

    }

    return next();

  }

  bool parseFreeStringInto(std::string &String) {

    do {

      if (!skipEscapeCharacter()) 
return false0
;

      String.push_back(*Position);

      if (!next()) 
return false114
;

    } while (*Position != ' ' && 
*Position != '"'20.9k
 && 
*Position != '\''20.9k
);

    return true;

  }

  bool skipEscapeCharacter() {

    if (*Position == '\\') {

      return next();

    }

    return true;

  }

  bool nextNonWhitespace() {

    do {

      if (!next()) 
return false3
;

    } while (*Position == ' ');

    return true;

  }

  bool next() {

    ++Position;

    return Position != Input.end();

  }

  const StringRef Input;

  StringRef::iterator Position;

  std::vector<std::string> CommandLine;

};

std::vector<std::string> unescapeCommandLine(JSONCommandLineSyntax Syntax,

                                             StringRef EscapedCommandLine) {

  if (Syntax == JSONCommandLineSyntax::AutoDetect) {

    Syntax = JSONCommandLineSyntax::Gnu;

    llvm::Triple Triple(llvm::sys::getProcessTriple());

    if (Triple.getOS() == llvm::Triple::OSType::Win32) {

      // Assume Windows command line parsing on Win32 unless the triple

      // explicitly tells us otherwise.

      if (!Triple.hasEnvironment() ||

          Triple.getEnvironment() == llvm::Triple::EnvironmentType::MSVC)

        Syntax = JSONCommandLineSyntax::Windows;

    }

  }

  if (Syntax == JSONCommandLineSyntax::Windows) {

    llvm::BumpPtrAllocator Alloc;

    llvm::StringSaver Saver(Alloc);

    llvm::SmallVector<const char *, 64> T;

    llvm::cl::TokenizeWindowsCommandLine(EscapedCommandLine, Saver, T);

    std::vector<std::string> Result(T.begin(), T.end());

    return Result;

  }

  assert(Syntax == JSONCommandLineSyntax::Gnu);

  CommandLineArgumentParser parser(EscapedCommandLine);

  return parser.parse();

}

// This plugin locates a nearby compile_command.json file, and also infers

// compile commands for files not present in the database.

class JSONCompilationDatabasePlugin : public CompilationDatabasePlugin {

  std::unique_ptr<CompilationDatabase>

  loadFromDirectory(StringRef Directory, std::string &ErrorMessage) override {

    SmallString<1024> JSONDatabasePath(Directory);

    llvm::sys::path::append(JSONDatabasePath, "compile_commands.json");

    auto Base = JSONCompilationDatabase::loadFromFile(

        JSONDatabasePath, ErrorMessage, JSONCommandLineSyntax::AutoDetect);

    return Base ? inferTargetAndDriverMode(

                      inferMissingCompileCommands(expandResponseFiles(

                          std::move(Base), llvm::vfs::getRealFileSystem())))

                : nullptr;

  }

};

} // namespace

// Register the JSONCompilationDatabasePlugin with the

// CompilationDatabasePluginRegistry using this statically initialized variable.

static CompilationDatabasePluginRegistry::Add<JSONCompilationDatabasePlugin>

X("json-compilation-database", "Reads JSON formatted compilation databases");

namespace clang {

namespace tooling {

// This anchor is used to force the linker to link in the generated object file

// and thus register the JSONCompilationDatabasePlugin.

volatile int JSONAnchorSource = 0;

} // namespace tooling

} // namespace clang

std::unique_ptr<JSONCompilationDatabase>

JSONCompilationDatabase::loadFromFile(StringRef FilePath,

                                      std::string &ErrorMessage,

                                      JSONCommandLineSyntax Syntax) {

  // Don't mmap: if we're a long-lived process, the build system may overwrite.

  llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>> DatabaseBuffer =

      llvm::MemoryBuffer::getFile(FilePath, /*FileSize=*/-1,

                                  /*RequiresNullTerminator=*/true,

                                  /*IsVolatile=*/true);

  if (std::error_code Result = DatabaseBuffer.getError()) {

    ErrorMessage = "Error while opening JSON database: " + Result.message();

    return nullptr;

  }

  std::unique_ptr<JSONCompilationDatabase> Database(

      new JSONCompilationDatabase(std::move(*DatabaseBuffer), Syntax));

  if (!Database->parse(ErrorMessage))

    return nullptr;

  return Database;

}

std::unique_ptr<JSONCompilationDatabase>

JSONCompilationDatabase::loadFromBuffer(StringRef DatabaseString,

                                        std::string &ErrorMessage,

                                        JSONCommandLineSyntax Syntax) {

  std::unique_ptr<llvm::MemoryBuffer> DatabaseBuffer(

      llvm::MemoryBuffer::getMemBufferCopy(DatabaseString));

  std::unique_ptr<JSONCompilationDatabase> Database(

      new JSONCompilationDatabase(std::move(DatabaseBuffer), Syntax));

  if (!Database->parse(ErrorMessage))

    return nullptr;

  return Database;

}

std::vector<CompileCommand>

JSONCompilationDatabase::getCompileCommands(StringRef FilePath) const {

  SmallString<128> NativeFilePath;

  llvm::sys::path::native(FilePath, NativeFilePath);

  std::string Error;

  llvm::raw_string_ostream ES(Error);

  StringRef Match = MatchTrie.findEquivalent(NativeFilePath, ES);

  if (Match.empty())

    return {};

  const auto CommandsRefI = IndexByFile.find(Match);

  if (CommandsRefI == IndexByFile.end())

    return {};

  std::vector<CompileCommand> Commands;

  getCommands(CommandsRefI->getValue(), Commands);

  return Commands;

}

std::vector<std::string>

JSONCompilationDatabase::getAllFiles() const {

  std::vector<std::string> Result;

  for (const auto &CommandRef : IndexByFile)

    Result.push_back(CommandRef.first().str());

  return Result;

}

std::vector<CompileCommand>

JSONCompilationDatabase::getAllCompileCommands() const {

  std::vector<CompileCommand> Commands;

  getCommands(AllCommands, Commands);

  return Commands;

}

static llvm::StringRef stripExecutableExtension(llvm::StringRef Name) {

  Name.consume_back(".exe");

  return Name;

}

// There are compiler-wrappers (ccache, distcc, gomacc) that take the "real"

// compiler as an argument, e.g. distcc gcc -O3 foo.c.

// These end up in compile_commands.json when people set CC="distcc gcc".

// Clang's driver doesn't understand this, so we need to unwrap.

static bool unwrapCommand(std::vector<std::string> &Args) {

  if (Args.size() < 2)

    return false;

  StringRef Wrapper =

      stripExecutableExtension(llvm::sys::path::filename(Args.front()));

  if (Wrapper == "distcc" || 
Wrapper == "gomacc"113
 || 
Wrapper == "ccache"112
 ||

      Wrapper == "sccache") {

    // Most of these wrappers support being invoked 3 ways:

    // `distcc g++ file.c` This is the mode we're trying to match.

    //                     We need to drop `distcc`.

    // `distcc file.c`     This acts like compiler is cc or similar.

    //                     Clang's driver can handle this, no change needed.

    // `g++ file.c`        g++ is a symlink to distcc.

    //                     We don't even notice this case, and all is well.

    //

    // We need to distinguish between the first and second case.

    // The wrappers themselves don't take flags, so Args[1] is a compiler flag,

    // an input file, or a compiler. Inputs have extensions, compilers don't.

    bool HasCompiler =

        (Args[1][0] != '-') &&

        !llvm::sys::path::has_extension(stripExecutableExtension(Args[1]));

    if (HasCompiler) {

      Args.erase(Args.begin());

      return true;

    }

    // If !HasCompiler, wrappers act like GCC. Fine: so do we.

  }

  return false;

}

static std::vector<std::string>

nodeToCommandLine(JSONCommandLineSyntax Syntax,

                  const std::vector<llvm::yaml::ScalarNode *> &Nodes) {

  SmallString<1024> Storage;

  std::vector<std::string> Arguments;

  if (Nodes.size() == 1)

    Arguments = unescapeCommandLine(Syntax, Nodes[0]->getValue(Storage));

  else

    for (const auto *Node : Nodes)

      Arguments.push_back(std::string(Node->getValue(Storage)));

  // There may be multiple wrappers: using distcc and ccache together is common.

  while (unwrapCommand(Arguments))

    ;

  return Arguments;

}

void JSONCompilationDatabase::getCommands(

    ArrayRef<CompileCommandRef> CommandsRef,

    std::vector<CompileCommand> &Commands) const {

  for (const auto &CommandRef : CommandsRef) {

    SmallString<8> DirectoryStorage;

    SmallString<32> FilenameStorage;

    SmallString<32> OutputStorage;

    auto Output = std::get<3>(CommandRef);

    Commands.emplace_back(

        std::get<0>(CommandRef)->getValue(DirectoryStorage),

        std::get<1>(CommandRef)->getValue(FilenameStorage),

        nodeToCommandLine(Syntax, std::get<2>(CommandRef)),

        Output ? 
Output->getValue(OutputStorage)1
 : "");

  }

}

bool JSONCompilationDatabase::parse(std::string &ErrorMessage) {

  llvm::yaml::document_iterator I = YAMLStream.begin();

  if (I == YAMLStream.end()) {

    ErrorMessage = "Error while parsing YAML.";

    return false;

  }

  llvm::yaml::Node *Root = I->getRoot();

  if (!Root) {

    ErrorMessage = "Error while parsing YAML.";

    return false;

  }

  auto *Array = dyn_cast<llvm::yaml::SequenceNode>(Root);

  if (!Array) {

    ErrorMessage = "Expected array.";

    return false;

  }

  
for (auto &NextObject : *Array)99
 {

    auto *Object = dyn_cast<llvm::yaml::MappingNode>(&NextObject);

    if (!Object) {

      ErrorMessage = "Expected object.";

      return false;

    }

    llvm::yaml::ScalarNode *Directory = nullptr;

    llvm::Optional<std::vector<llvm::yaml::ScalarNode *>> Command;

    llvm::yaml::ScalarNode *File = nullptr;

    llvm::yaml::ScalarNode *Output = nullptr;

    for (auto& NextKeyValue : *Object) {

      auto *KeyString = dyn_cast<llvm::yaml::ScalarNode>(NextKeyValue.getKey());

      if (!KeyString) {

        ErrorMessage = "Expected strings as key.";

        return false;

      }

      SmallString<10> KeyStorage;

      StringRef KeyValue = KeyString->getValue(KeyStorage);

      llvm::yaml::Node *Value = NextKeyValue.getValue();

      if (!Value) {

        ErrorMessage = "Expected value.";

        return false;

      }

      auto *ValueString = dyn_cast<llvm::yaml::ScalarNode>(Value);

      auto *SequenceString = dyn_cast<llvm::yaml::SequenceNode>(Value);

      if (KeyValue == "arguments") {

        if (!SequenceString) {

          ErrorMessage = "Expected sequence as value.";

          return false;

        }

        Command = std::vector<llvm::yaml::ScalarNode *>();

        for (auto &Argument : *SequenceString) {

          auto *Scalar = dyn_cast<llvm::yaml::ScalarNode>(&Argument);

          if (!Scalar) {

            ErrorMessage = "Only strings are allowed in 'arguments'.";

            return false;

          }

          Command->push_back(Scalar);

        }

      } else {

        if (!ValueString) {

          ErrorMessage = "Expected string as value.";

          return false;

        }

        if (KeyValue == "directory") {

          Directory = ValueString;

        } else if (KeyValue == "command") {

          if (!Command)

            Command = std::vector<llvm::yaml::ScalarNode *>(1, ValueString);

        } else if (KeyValue == "file") {

          File = ValueString;

        } else if (KeyValue == "output") {

          Output = ValueString;

        } else {

          ErrorMessage =

              ("Unknown key: \"" + KeyString->getRawValue() + "\"").str();

          return false;

        }

      }

    }

    if (!File) {

      ErrorMessage = "Missing key: \"file\".";

      return false;

    }

    if (!Command) {

      ErrorMessage = "Missing key: \"command\" or \"arguments\".";

      return false;

    }

    if (!Directory) {

      ErrorMessage = "Missing key: \"directory\".";

      return false;

    }

    SmallString<8> FileStorage;

    StringRef FileName = File->getValue(FileStorage);

    SmallString<128> NativeFilePath;

    if (llvm::sys::path::is_relative(FileName)) {

      SmallString<8> DirectoryStorage;

      SmallString<128> AbsolutePath(

          Directory->getValue(DirectoryStorage));

      llvm::sys::path::append(AbsolutePath, FileName);

      llvm::sys::path::remove_dots(AbsolutePath, /*remove_dot_dot=*/ true);

      llvm::sys::path::native(AbsolutePath, NativeFilePath);

    } else {

      llvm::sys::path::native(FileName, NativeFilePath);

    }

    auto Cmd = CompileCommandRef(Directory, File, *Command, Output);

    IndexByFile[NativeFilePath].push_back(Cmd);

    AllCommands.push_back(Cmd);

    MatchTrie.insert(NativeFilePath);

  }

  return true;

}