output.cc

// Copyright (c) 2015-2017 DMOJ: Modern Online Judge. All rights reserved.
// 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.
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//       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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// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

#include "v8dmoj.h"

#include <cstdio>

static bool autoflush = false;

// The callback that is invoked by v8 whenever the JavaScript 'print'
// function is called.  Prints its arguments on stdout separated by
// spaces and ending with a newline.
static void Print(const v8::FunctionCallbackInfo<v8::Value> &args) {
  bool first = true;
  for (int i = 0; i < args.Length(); i++) {
    v8::HandleScope handle_scope(args.GetIsolate());
    if (first) {
      first = false;
    } else {
      std::putchar(' ');
    }
    v8::String::Utf8Value str(args.GetIsolate(), args[i]);
    std::fputs(ToCString(str), stdout);
  }
  std::putchar('\n');
  if (autoflush) std::fflush(stdout);
}

static void Flush(const v8::FunctionCallbackInfo<v8::Value> &args) {
  std::fflush(stdout);
}

static void GetAutoflush(v8::Local<v8::String> property,
                         const v8::PropertyCallbackInfo<v8::Value> &info) {
  info.GetReturnValue().Set(v8::Boolean::New(info.GetIsolate(), autoflush));
}

static void SetAutoflush(v8::Local<v8::String> property,
                         v8::Local<v8::Value> value,
                         const v8::PropertyCallbackInfo<void> &info) {
  autoflush = value->BooleanValue(info.GetIsolate());
}

void InitializeOutputModule(v8::Isolate *isolate,
                            v8::Local<v8::ObjectTemplate> &global) {
  // Bind the global 'print' function to the C++ Print callback.
  global->Set(
      v8::String::NewFromUtf8(isolate, "print", v8::NewStringType::kNormal)
          .ToLocalChecked(),
      v8::FunctionTemplate::New(isolate, Print));

  // Bind the global 'flush' function to the C++ Flush callback.
  global->Set(
      v8::String::NewFromUtf8(isolate, "flush", v8::NewStringType::kNormal)
          .ToLocalChecked(),
      v8::FunctionTemplate::New(isolate, Flush));

  // Bind the global 'autoflush' property to the autoflush variable.
  global->SetAccessor(
      v8::String::NewFromUtf8(isolate, "autoflush", v8::NewStringType::kNormal)
          .ToLocalChecked(),
      GetAutoflush, SetAutoflush);
}