//===--- CompilationDatabase.cpp - ----------------------------------------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
//  This file contains multiple implementations for CompilationDatabases.
//
//===----------------------------------------------------------------------===//

#include "clang/Tooling/CompilationDatabase.h"
#include "clang/Tooling/Tooling.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/Support/YAMLParser.h"
#include "llvm/Support/Path.h"
#include "llvm/Support/system_error.h"

namespace clang {
namespace tooling {

namespace {

/// \brief 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()) {
      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 (!parseQuotedStringInto(String)) return false;
      } else {
        if (!parseFreeStringInto(String)) return false;
      }
    } while (*Position != ' ');
    return true;
  }

  bool parseQuotedStringInto(std::string &String) {
    if (!next()) return false;
    while (*Position != '"') {
      if (!skipEscapeCharacter()) return false;
      String.push_back(*Position);
      if (!next()) return false;
    }
    return next();
  }

  bool parseFreeStringInto(std::string &String) {
    do {
      if (!skipEscapeCharacter()) return false;
      String.push_back(*Position);
      if (!next()) return false;
    } while (*Position != ' ' && *Position != '"');
    return true;
  }

  bool skipEscapeCharacter() {
    if (*Position == '\\') {
      return next();
    }
    return true;
  }

  bool nextNonWhitespace() {
    do {
      if (!next()) return false;
    } 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(
    StringRef EscapedCommandLine) {
  CommandLineArgumentParser parser(EscapedCommandLine);
  return parser.parse();
}

} // end namespace

CompilationDatabase::~CompilationDatabase() {}

CompilationDatabase *
CompilationDatabase::loadFromDirectory(StringRef BuildDirectory,
                                       std::string &ErrorMessage) {
  llvm::SmallString<1024> JSONDatabasePath(BuildDirectory);
  llvm::sys::path::append(JSONDatabasePath, "compile_commands.json");
  llvm::OwningPtr<CompilationDatabase> Database(
    JSONCompilationDatabase::loadFromFile(JSONDatabasePath, ErrorMessage));
  if (!Database) {
    return NULL;
  }
  return Database.take();
}

static CompilationDatabase *
findCompilationDatabaseFromDirectory(StringRef Directory) {
  while (!Directory.empty()) {
    std::string LoadErrorMessage;

    if (CompilationDatabase *DB =
           CompilationDatabase::loadFromDirectory(Directory, LoadErrorMessage))
      return DB;

    Directory = llvm::sys::path::parent_path(Directory);
  }
  return NULL;
}

CompilationDatabase *
CompilationDatabase::autoDetectFromSource(StringRef SourceFile,
                                          std::string &ErrorMessage) {
  llvm::SmallString<1024> AbsolutePath(getAbsolutePath(SourceFile));
  StringRef Directory = llvm::sys::path::parent_path(AbsolutePath);

  CompilationDatabase *DB = findCompilationDatabaseFromDirectory(Directory);

  if (!DB)
    ErrorMessage = ("Could not auto-detect compilation database for file \"" +
                   SourceFile + "\"").str();
  return DB;
}

CompilationDatabase *
CompilationDatabase::autoDetectFromDirectory(StringRef SourceDir,
                                             std::string &ErrorMessage) {
  llvm::SmallString<1024> AbsolutePath(getAbsolutePath(SourceDir));

  CompilationDatabase *DB = findCompilationDatabaseFromDirectory(AbsolutePath);

  if (!DB)
    ErrorMessage = ("Could not auto-detect compilation database from directory \"" +
                   SourceDir + "\"").str();
  return DB;
}

FixedCompilationDatabase *
FixedCompilationDatabase::loadFromCommandLine(int &Argc,
                                              const char **Argv,
                                              Twine Directory) {
  const char **DoubleDash = std::find(Argv, Argv + Argc, StringRef("--"));
  if (DoubleDash == Argv + Argc)
    return NULL;
  std::vector<std::string> CommandLine(DoubleDash + 1, Argv + Argc);
  Argc = DoubleDash - Argv;
  return new FixedCompilationDatabase(Directory, CommandLine);
}

FixedCompilationDatabase::
FixedCompilationDatabase(Twine Directory, ArrayRef<std::string> CommandLine) {
  std::vector<std::string> ToolCommandLine(1, "clang-tool");
  ToolCommandLine.insert(ToolCommandLine.end(),
                         CommandLine.begin(), CommandLine.end());
  CompileCommands.push_back(CompileCommand(Directory, ToolCommandLine));
}

std::vector<CompileCommand>
FixedCompilationDatabase::getCompileCommands(StringRef FilePath) const {
  std::vector<CompileCommand> Result(CompileCommands);
  Result[0].CommandLine.push_back(FilePath);
  return Result;
}

JSONCompilationDatabase *
JSONCompilationDatabase::loadFromFile(StringRef FilePath,
                                      std::string &ErrorMessage) {
  llvm::OwningPtr<llvm::MemoryBuffer> DatabaseBuffer;
  llvm::error_code Result =
    llvm::MemoryBuffer::getFile(FilePath, DatabaseBuffer);
  if (Result != 0) {
    ErrorMessage = "Error while opening JSON database: " + Result.message();
    return NULL;
  }
  llvm::OwningPtr<JSONCompilationDatabase> Database(
    new JSONCompilationDatabase(DatabaseBuffer.take()));
  if (!Database->parse(ErrorMessage))
    return NULL;
  return Database.take();
}

JSONCompilationDatabase *
JSONCompilationDatabase::loadFromBuffer(StringRef DatabaseString,
                                        std::string &ErrorMessage) {
  llvm::OwningPtr<llvm::MemoryBuffer> DatabaseBuffer(
      llvm::MemoryBuffer::getMemBuffer(DatabaseString));
  llvm::OwningPtr<JSONCompilationDatabase> Database(
    new JSONCompilationDatabase(DatabaseBuffer.take()));
  if (!Database->parse(ErrorMessage))
    return NULL;
  return Database.take();
}

std::vector<CompileCommand>
JSONCompilationDatabase::getCompileCommands(StringRef FilePath) const {
  llvm::SmallString<128> NativeFilePath;
  llvm::sys::path::native(FilePath, NativeFilePath);
  llvm::StringMap< std::vector<CompileCommandRef> >::const_iterator
    CommandsRefI = IndexByFile.find(NativeFilePath);
  if (CommandsRefI == IndexByFile.end())
    return std::vector<CompileCommand>();
  const std::vector<CompileCommandRef> &CommandsRef = CommandsRefI->getValue();
  std::vector<CompileCommand> Commands;
  for (int I = 0, E = CommandsRef.size(); I != E; ++I) {
    llvm::SmallString<8> DirectoryStorage;
    llvm::SmallString<1024> CommandStorage;
    Commands.push_back(CompileCommand(
      // FIXME: Escape correctly:
      CommandsRef[I].first->getValue(DirectoryStorage),
      unescapeCommandLine(CommandsRef[I].second->getValue(CommandStorage))));
  }
  return Commands;
}

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 == NULL) {
    ErrorMessage = "Error while parsing YAML.";
    return false;
  }
  llvm::yaml::SequenceNode *Array =
    llvm::dyn_cast<llvm::yaml::SequenceNode>(Root);
  if (Array == NULL) {
    ErrorMessage = "Expected array.";
    return false;
  }
  for (llvm::yaml::SequenceNode::iterator AI = Array->begin(),
                                          AE = Array->end();
       AI != AE; ++AI) {
    llvm::yaml::MappingNode *Object =
      llvm::dyn_cast<llvm::yaml::MappingNode>(&*AI);
    if (Object == NULL) {
      ErrorMessage = "Expected object.";
      return false;
    }
    llvm::yaml::ScalarNode *Directory = NULL;
    llvm::yaml::ScalarNode *Command = NULL;
    llvm::yaml::ScalarNode *File = NULL;
    for (llvm::yaml::MappingNode::iterator KVI = Object->begin(),
                                           KVE = Object->end();
         KVI != KVE; ++KVI) {
      llvm::yaml::Node *Value = (*KVI).getValue();
      if (Value == NULL) {
        ErrorMessage = "Expected value.";
        return false;
      }
      llvm::yaml::ScalarNode *ValueString =
        llvm::dyn_cast<llvm::yaml::ScalarNode>(Value);
      if (ValueString == NULL) {
        ErrorMessage = "Expected string as value.";
        return false;
      }
      llvm::yaml::ScalarNode *KeyString =
        llvm::dyn_cast<llvm::yaml::ScalarNode>((*KVI).getKey());
      if (KeyString == NULL) {
        ErrorMessage = "Expected strings as key.";
        return false;
      }
      llvm::SmallString<8> KeyStorage;
      if (KeyString->getValue(KeyStorage) == "directory") {
        Directory = ValueString;
      } else if (KeyString->getValue(KeyStorage) == "command") {
        Command = ValueString;
      } else if (KeyString->getValue(KeyStorage) == "file") {
        File = ValueString;
      } else {
        ErrorMessage = ("Unknown key: \"" +
                        KeyString->getRawValue() + "\"").str();
        return false;
      }
    }
    if (!File) {
      ErrorMessage = "Missing key: \"file\".";
      return false;
    }
    if (!Command) {
      ErrorMessage = "Missing key: \"command\".";
      return false;
    }
    if (!Directory) {
      ErrorMessage = "Missing key: \"directory\".";
      return false;
    }
    llvm::SmallString<8> FileStorage;
    llvm::SmallString<128> NativeFilePath;
    llvm::sys::path::native(File->getValue(FileStorage), NativeFilePath);
    IndexByFile[NativeFilePath].push_back(
      CompileCommandRef(Directory, Command));
  }
  return true;
}

} // end namespace tooling
} // end namespace clang