/*
 * Copyright 2015 Facebook, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include <folly/io/IOBufQueue.h>
#include <folly/Range.h>

#include <gflags/gflags.h>
#include <gtest/gtest.h>

#include <iostream>
#include <stdexcept>
#include <string.h>

using folly::IOBuf;
using folly::IOBufQueue;
using folly::StringPiece;
using std::pair;
using std::string;
using std::unique_ptr;

// String Comma Length macro for string literals
#define SCL(x) (x), sizeof(x) - 1

namespace {

IOBufQueue::Options clOptions;
struct Initializer {
  Initializer() {
    clOptions.cacheChainLength = true;
  }
};
Initializer initializer;

unique_ptr<IOBuf>
stringToIOBuf(const char* s, uint32_t len) {
  unique_ptr<IOBuf> buf = IOBuf::create(len);
  memcpy(buf->writableTail(), s, len);
  buf->append(len);
  return buf;
}

void checkConsistency(const IOBufQueue& queue) {
  if (queue.options().cacheChainLength) {
    size_t len = queue.front() ? queue.front()->computeChainDataLength() : 0;
    EXPECT_EQ(len, queue.chainLength());
  }
}

}

TEST(IOBufQueue, Simple) {
  IOBufQueue queue(clOptions);
  EXPECT_EQ(nullptr, queue.front());
  queue.append(SCL(""));
  EXPECT_EQ(nullptr, queue.front());
  queue.append(unique_ptr<IOBuf>());
  EXPECT_EQ(nullptr, queue.front());
  string emptyString;
  queue.append(emptyString);
  EXPECT_EQ(nullptr, queue.front());
}

TEST(IOBufQueue, Append) {
  IOBufQueue queue(clOptions);
  queue.append(SCL("Hello"));
  IOBufQueue queue2(clOptions);
  queue2.append(SCL(", "));
  queue2.append(SCL("World"));
  checkConsistency(queue);
  checkConsistency(queue2);
  queue.append(queue2.move());
  checkConsistency(queue);
  checkConsistency(queue2);
  const IOBuf* chain = queue.front();
  EXPECT_NE((IOBuf*)nullptr, chain);
  EXPECT_EQ(12, chain->computeChainDataLength());
  EXPECT_EQ(nullptr, queue2.front());
}

TEST(IOBufQueue, Append2) {
  IOBufQueue queue(clOptions);
  queue.append(SCL("Hello"));
  IOBufQueue queue2(clOptions);
  queue2.append(SCL(", "));
  queue2.append(SCL("World"));
  checkConsistency(queue);
  checkConsistency(queue2);
  queue.append(queue2);
  checkConsistency(queue);
  checkConsistency(queue2);
  const IOBuf* chain = queue.front();
  EXPECT_NE((IOBuf*)nullptr, chain);
  EXPECT_EQ(12, chain->computeChainDataLength());
  EXPECT_EQ(nullptr, queue2.front());
}

TEST(IOBufQueue, AppendStringPiece) {
  std::string s("Hello, World");
  IOBufQueue queue(clOptions);
  IOBufQueue queue2(clOptions);
  queue.append(s.data(), s.length());
  queue2.append(s);
  checkConsistency(queue);
  checkConsistency(queue2);
  const IOBuf* chain = queue.front();
  const IOBuf* chain2 = queue2.front();
  EXPECT_EQ(s.length(), chain->computeChainDataLength());
  EXPECT_EQ(s.length(), chain2->computeChainDataLength());
  EXPECT_EQ(0, memcmp(chain->data(), chain2->data(), s.length()));
}

TEST(IOBufQueue, Split) {
  IOBufQueue queue(clOptions);
  queue.append(stringToIOBuf(SCL("Hello")));
  queue.append(stringToIOBuf(SCL(",")));
  queue.append(stringToIOBuf(SCL(" ")));
  queue.append(stringToIOBuf(SCL("")));
  queue.append(stringToIOBuf(SCL("World")));
  checkConsistency(queue);
  EXPECT_EQ(12, queue.front()->computeChainDataLength());

  unique_ptr<IOBuf> prefix(queue.split(1));
  checkConsistency(queue);
  EXPECT_EQ(1, prefix->computeChainDataLength());
  EXPECT_EQ(11, queue.front()->computeChainDataLength());
  prefix = queue.split(2);
  checkConsistency(queue);
  EXPECT_EQ(2, prefix->computeChainDataLength());
  EXPECT_EQ(9, queue.front()->computeChainDataLength());
  prefix = queue.split(3);
  checkConsistency(queue);
  EXPECT_EQ(3, prefix->computeChainDataLength());
  EXPECT_EQ(6, queue.front()->computeChainDataLength());
  prefix = queue.split(1);
  checkConsistency(queue);
  EXPECT_EQ(1, prefix->computeChainDataLength());
  EXPECT_EQ(5, queue.front()->computeChainDataLength());
  prefix = queue.split(5);
  checkConsistency(queue);
  EXPECT_EQ(5, prefix->computeChainDataLength());
  EXPECT_EQ((IOBuf*)nullptr, queue.front());

  queue.append(stringToIOBuf(SCL("Hello,")));
  queue.append(stringToIOBuf(SCL(" World")));
  checkConsistency(queue);
  EXPECT_THROW({prefix = queue.split(13);}, std::underflow_error);
  checkConsistency(queue);
}

TEST(IOBufQueue, Preallocate) {
  IOBufQueue queue(clOptions);
  queue.append(string("Hello"));
  pair<void*,uint32_t> writable = queue.preallocate(2, 64, 64);
  checkConsistency(queue);
  EXPECT_NE((void*)nullptr, writable.first);
  EXPECT_LE(2, writable.second);
  EXPECT_GE(64, writable.second);
  memcpy(writable.first, SCL(", "));
  queue.postallocate(2);
  checkConsistency(queue);
  EXPECT_EQ(7, queue.front()->computeChainDataLength());
  queue.append(SCL("World"));
  checkConsistency(queue);
  EXPECT_EQ(12, queue.front()->computeChainDataLength());
  // There are not 2048 bytes available, this will alloc a new buf
  writable = queue.preallocate(2048, 4096);
  checkConsistency(queue);
  EXPECT_LE(2048, writable.second);
  // IOBuf allocates more than newAllocationSize, and we didn't cap it
  EXPECT_GE(writable.second, 4096);
  queue.postallocate(writable.second);
  // queue has no empty space, make sure we allocate at least min, even if
  // newAllocationSize < min
  writable = queue.preallocate(1024, 1, 1024);
  checkConsistency(queue);
  EXPECT_EQ(1024, writable.second);
}

TEST(IOBufQueue, Wrap) {
  IOBufQueue queue(clOptions);
  const char* buf = "hello world goodbye";
  size_t len = strlen(buf);
  queue.wrapBuffer(buf, len, 6);
  auto iob = queue.move();
  EXPECT_EQ((len - 1) / 6 + 1, iob->countChainElements());
  iob->unshare();
  iob->coalesce();
  EXPECT_EQ(StringPiece(buf),
            StringPiece(reinterpret_cast<const char*>(iob->data()),
                        iob->length()));
}

TEST(IOBufQueue, Trim) {
  IOBufQueue queue(clOptions);
  unique_ptr<IOBuf> a = IOBuf::create(4);
  a->append(4);
  queue.append(std::move(a));
  checkConsistency(queue);
  a = IOBuf::create(6);
  a->append(6);
  queue.append(std::move(a));
  checkConsistency(queue);
  a = IOBuf::create(8);
  a->append(8);
  queue.append(std::move(a));
  checkConsistency(queue);
  a = IOBuf::create(10);
  a->append(10);
  queue.append(std::move(a));
  checkConsistency(queue);

  EXPECT_EQ(4, queue.front()->countChainElements());
  EXPECT_EQ(28, queue.front()->computeChainDataLength());
  EXPECT_EQ(4, queue.front()->length());

  queue.trimStart(1);
  checkConsistency(queue);
  EXPECT_EQ(4, queue.front()->countChainElements());
  EXPECT_EQ(27, queue.front()->computeChainDataLength());
  EXPECT_EQ(3, queue.front()->length());

  queue.trimStart(5);
  checkConsistency(queue);
  EXPECT_EQ(3, queue.front()->countChainElements());
  EXPECT_EQ(22, queue.front()->computeChainDataLength());
  EXPECT_EQ(4, queue.front()->length());

  queue.trimEnd(1);
  checkConsistency(queue);
  EXPECT_EQ(3, queue.front()->countChainElements());
  EXPECT_EQ(21, queue.front()->computeChainDataLength());
  EXPECT_EQ(9, queue.front()->prev()->length());

  queue.trimEnd(20);
  checkConsistency(queue);
  EXPECT_EQ(1, queue.front()->countChainElements());
  EXPECT_EQ(1, queue.front()->computeChainDataLength());
  EXPECT_EQ(1, queue.front()->prev()->length());

  queue.trimEnd(1);
  checkConsistency(queue);
  EXPECT_EQ(nullptr, queue.front());

  EXPECT_THROW(queue.trimStart(2), std::underflow_error);
  checkConsistency(queue);

  EXPECT_THROW(queue.trimEnd(30), std::underflow_error);
  checkConsistency(queue);
}

TEST(IOBufQueue, TrimPack) {
  IOBufQueue queue(clOptions);
  unique_ptr<IOBuf> a = IOBuf::create(64);
  a->append(4);
  queue.append(std::move(a), true);
  checkConsistency(queue);
  a = IOBuf::create(6);
  a->append(6);
  queue.append(std::move(a), true);
  checkConsistency(queue);
  a = IOBuf::create(8);
  a->append(8);
  queue.append(std::move(a), true);
  checkConsistency(queue);
  a = IOBuf::create(10);
  a->append(10);
  queue.append(std::move(a), true);
  checkConsistency(queue);

  EXPECT_EQ(1, queue.front()->countChainElements());
  EXPECT_EQ(28, queue.front()->computeChainDataLength());
  EXPECT_EQ(28, queue.front()->length());

  queue.trimStart(1);
  checkConsistency(queue);
  EXPECT_EQ(1, queue.front()->countChainElements());
  EXPECT_EQ(27, queue.front()->computeChainDataLength());
  EXPECT_EQ(27, queue.front()->length());

  queue.trimStart(5);
  checkConsistency(queue);
  EXPECT_EQ(1, queue.front()->countChainElements());
  EXPECT_EQ(22, queue.front()->computeChainDataLength());
  EXPECT_EQ(22, queue.front()->length());

  queue.trimEnd(1);
  checkConsistency(queue);
  EXPECT_EQ(1, queue.front()->countChainElements());
  EXPECT_EQ(21, queue.front()->computeChainDataLength());
  EXPECT_EQ(21, queue.front()->prev()->length());

  queue.trimEnd(20);
  checkConsistency(queue);
  EXPECT_EQ(1, queue.front()->countChainElements());
  EXPECT_EQ(1, queue.front()->computeChainDataLength());
  EXPECT_EQ(1, queue.front()->prev()->length());

  queue.trimEnd(1);
  checkConsistency(queue);
  EXPECT_EQ(nullptr, queue.front());

  EXPECT_THROW(queue.trimStart(2), std::underflow_error);
  checkConsistency(queue);

  EXPECT_THROW(queue.trimEnd(30), std::underflow_error);
  checkConsistency(queue);
}

TEST(IOBufQueue, Prepend) {
  folly::IOBufQueue queue;

  auto buf = folly::IOBuf::create(10);
  buf->advance(5);
  queue.append(std::move(buf));

  queue.append(SCL(" World"));
  queue.prepend(SCL("Hello"));

  EXPECT_THROW(queue.prepend(SCL("x")), std::overflow_error);

  auto out = queue.move();
  out->coalesce();
  EXPECT_EQ("Hello World",
            StringPiece(reinterpret_cast<const char*>(out->data()),
                        out->length()));
}

TEST(IOBufQueue, PopFirst) {
  IOBufQueue queue(IOBufQueue::cacheChainLength());
  const char * strings[] = {
    "Hello",
    ",",
    " ",
    "",
    "World"
  };

  const size_t numStrings=sizeof(strings)/sizeof(*strings);
  size_t chainLength = 0;
  for(size_t i = 0; i < numStrings; ++i) {
    queue.append(stringToIOBuf(strings[i], strlen(strings[i])));
    checkConsistency(queue);
    chainLength += strlen(strings[i]);
  }

  unique_ptr<IOBuf> first;
  for(size_t i = 0; i < numStrings; ++i) {
    checkConsistency(queue);
    EXPECT_EQ(chainLength, queue.front()->computeChainDataLength());
    EXPECT_EQ(chainLength, queue.chainLength());
    first = queue.pop_front();
    chainLength-=strlen(strings[i]);
    EXPECT_EQ(strlen(strings[i]), first->computeChainDataLength());
  }
  checkConsistency(queue);
  EXPECT_EQ(chainLength, queue.chainLength());

  EXPECT_EQ((IOBuf*)nullptr, queue.front());
  first = queue.pop_front();
  EXPECT_EQ((IOBuf*)nullptr, first.get());

  checkConsistency(queue);
  EXPECT_EQ((IOBuf*)nullptr, queue.front());
  EXPECT_EQ(0, queue.chainLength());
}

TEST(IOBufQueue, AppendToString) {
  IOBufQueue queue;
  queue.append("hello ", 6);
  queue.append("world", 5);
  std::string s;
  queue.appendToString(s);
  EXPECT_EQ("hello world", s);
}

int main(int argc, char** argv) {
  testing::InitGoogleTest(&argc, argv);
  gflags::ParseCommandLineFlags(&argc, &argv, true);

  return RUN_ALL_TESTS();
}
