src/d8-readline.cc

// Copyright 2012 the V8 project authors. All rights reserved.
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
//     * Redistributions of source code must retain the above copyright
//       notice, this list of conditions and the following disclaimer.
//     * Redistributions in binary form must reproduce the above
//       copyright notice, this list of conditions and the following
//       disclaimer in the documentation and/or other materials provided
//       with the distribution.
//     * Neither the name of Google Inc. nor the names of its
//       contributors may be used to endorse or promote products derived
//       from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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#include <cstdio>  // NOLINT
#include <readline/readline.h> // NOLINT
#include <readline/history.h> // NOLINT

// The readline includes leaves RETURN defined which breaks V8 compilation.
#undef RETURN

#include "d8.h"


// There are incompatibilities between different versions and different
// implementations of readline.  This smooths out one known incompatibility.
#if RL_READLINE_VERSION >= 0x0500
#define completion_matches rl_completion_matches
#endif


namespace v8 {


class ReadLineEditor: public LineEditor {
 public:
  ReadLineEditor() : LineEditor(LineEditor::READLINE, "readline") { }
  virtual Handle<String> Prompt(const char* prompt);
  virtual bool Open();
  virtual bool Close();
  virtual void AddHistory(const char* str);

  static const char* kHistoryFileName;
  static const int kMaxHistoryEntries;

 private:
  static char** AttemptedCompletion(const char* text, int start, int end);
  static char* CompletionGenerator(const char* text, int state);
  static char kWordBreakCharacters[];
};


static ReadLineEditor read_line_editor;
char ReadLineEditor::kWordBreakCharacters[] = {' ', '\t', '\n', '"',
    '\\', '\'', '`', '@', '.', '>', '<', '=', ';', '|', '&', '{', '(',
    '\0'};


const char* ReadLineEditor::kHistoryFileName = ".d8_history";
const int ReadLineEditor::kMaxHistoryEntries = 1000;


bool ReadLineEditor::Open() {
  rl_initialize();
  rl_attempted_completion_function = AttemptedCompletion;
  rl_completer_word_break_characters = kWordBreakCharacters;
  rl_bind_key('\t', rl_complete);
  using_history();
  stifle_history(kMaxHistoryEntries);
  return read_history(kHistoryFileName) == 0;
}


bool ReadLineEditor::Close() {
  return write_history(kHistoryFileName) == 0;
}


Handle<String> ReadLineEditor::Prompt(const char* prompt) {
  char* result = NULL;
  {  // Release lock for blocking input.
    Unlocker unlock(Isolate::GetCurrent());
    result = readline(prompt);
  }
  if (result != NULL) {
    AddHistory(result);
  } else {
    return Handle<String>();
  }
  return String::New(result);
}


void ReadLineEditor::AddHistory(const char* str) {
  // Do not record empty input.
  if (strlen(str) == 0) return;
  // Remove duplicate history entry.
  history_set_pos(history_length-1);
  if (current_history()) {
    do {
      if (strcmp(current_history()->line, str) == 0) {
        remove_history(where_history());
        break;
      }
    } while (previous_history());
  }
  add_history(str);
}


char** ReadLineEditor::AttemptedCompletion(const char* text,
                                           int start,
                                           int end) {
  char** result = completion_matches(text, CompletionGenerator);
  rl_attempted_completion_over = true;
  return result;
}


char* ReadLineEditor::CompletionGenerator(const char* text, int state) {
  static unsigned current_index;
  static Persistent<Array> current_completions;
  if (state == 0) {
    HandleScope scope;
    Local<String> full_text = String::New(rl_line_buffer, rl_point);
    Handle<Array> completions =
      Shell::GetCompletions(String::New(text), full_text);
    current_completions = Persistent<Array>::New(completions);
    current_index = 0;
  }
  if (current_index < current_completions->Length()) {
    HandleScope scope;
    Handle<Integer> index = Integer::New(current_index);
    Handle<Value> str_obj = current_completions->Get(index);
    current_index++;
    String::Utf8Value str(str_obj);
    return strdup(*str);
  } else {
    current_completions.Dispose();
    current_completions.Clear();
    return NULL;
  }
}


}  // namespace v8