// Copyright Joyent, Inc. and other Node contributors.

//

// Permission is hereby granted, free of charge, to any person obtaining a

// copy of this software and associated documentation files (the

// "Software"), to deal in the Software without restriction, including

// without limitation the rights to use, copy, modify, merge, publish,

// distribute, sublicense, and/or sell copies of the Software, and to permit

// persons to whom the Software is furnished to do so, subject to the

// following conditions:

//

// The above copyright notice and this permission notice shall be included

// in all copies or substantial portions of the Software.

//

// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS

// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF

// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN

// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,

// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR

// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE

// USE OR OTHER DEALINGS IN THE SOFTWARE.

#ifndef SRC_CRYPTO_CRYPTO_BIO_H_

#define SRC_CRYPTO_CRYPTO_BIO_H_

#if defined(NODE_WANT_INTERNALS) && NODE_WANT_INTERNALS

#include "node_crypto.h"

#include "openssl/bio.h"

#include "util.h"

#include "v8.h"

namespace node {

class Environment;

namespace crypto {

// This class represents buffers for OpenSSL I/O, implemented as a singly-linked

// list of chunks. It can be used either for writing data from Node to OpenSSL,

// or for reading data back, but not both.

// The structure is only accessed, and owned by, the OpenSSL BIOPointer

// (a.k.a. std::unique_ptr<BIO>).

class NodeBIO : public MemoryRetainer {

 public:

  ~NodeBIO() override;

  static ncrypto::BIOPointer New(Environment* env = nullptr);

  // NewFixed takes a copy of `len` bytes from `data` and returns a BIO that,

  // when read from, returns those bytes followed by EOF.

  static ncrypto::BIOPointer NewFixed(const char* data,

                                      size_t len,

                                      Environment* env = nullptr);

  // Move read head to next buffer if needed

  void TryMoveReadHead();

  // Allocate new buffer for write if needed

  void TryAllocateForWrite(size_t hint);

  // Read `len` bytes maximum into `out`, return actual number of read bytes

  size_t Read(char* out, size_t size);

  // Memory optimization:

  // Deallocate children of write head's child if they're empty

  void FreeEmpty();

  // Return pointer to internal data and amount of

  // contiguous data available to read

  char* Peek(size_t* size);

  // Return pointers and sizes of multiple internal data chunks available for

  // reading

  size_t PeekMultiple(char** out, size_t* size, size_t* count);

  // Find first appearance of `delim` in buffer or `limit` if `delim`

  // wasn't found.

  size_t IndexOf(char delim, size_t limit);

  // Discard all available data

  void Reset();

  // Put `len` bytes from `data` into buffer

  void Write(const char* data, size_t size);

  // Return pointer to contiguous block of reserved data and the size available

  // for future writes. Call Commit() once the write is complete.

  char* PeekWritable(size_t* size);

  // Specify how much data was written into the block returned by

  // PeekWritable().

  void Commit(size_t size);

  // Return size of buffer in bytes

  inline size_t Length() const {

    return length_;

  }

  // Provide a hint about the size of the next pending set of writes. TLS

  // writes records of a maximum length of 16k of data plus a 5-byte header,

  // a MAC (up to 20 bytes for SSLv3, TLS 1.0, TLS 1.1, and up to 32 bytes

  // for TLS 1.2), and padding if a block cipher is used.  If there is a

  // large write this will result in potentially many buffers being

  // allocated and gc'ed which can cause long pauses. By providing a

  // guess about the amount of buffer space that will be needed in the

  // next allocation this overhead is removed.

  inline void set_allocate_tls_hint(size_t size) {

    constexpr size_t kThreshold = 16 * 1024;

    if (size >= kThreshold) {

      allocate_hint_ = (size / kThreshold + 1) * (kThreshold + 5 + 32);

    }

  }

  inline void set_eof_return(int num) {

    eof_return_ = num;

  }

  inline int eof_return() {

    return eof_return_;

  }

  inline void set_initial(size_t initial) {

    initial_ = initial;

  }

  static NodeBIO* FromBIO(BIO* bio);

  void MemoryInfo(MemoryTracker* tracker) const override {

    tracker->TrackFieldWithSize("buffer", length_, "NodeBIO::Buffer");

  }

  SET_MEMORY_INFO_NAME(NodeBIO)

  SET_SELF_SIZE(NodeBIO)

 private:

  static int New(BIO* bio);

  static int Free(BIO* bio);

  static int Read(BIO* bio, char* out, int len);

  static int Write(BIO* bio, const char* data, int len);

  static int Puts(BIO* bio, const char* str);

  static int Gets(BIO* bio, char* out, int size);

  static long Ctrl(BIO* bio, int cmd, long num,  // NOLINT(runtime/int)

                   void* ptr);

  static const BIO_METHOD* GetMethod();

  // Enough to handle the most of the client hellos

  static const size_t kInitialBufferLength = 1024;

  static const size_t kThroughputBufferLength = 16384;

  class Buffer {

   public:

    Buffer(Environment* env, size_t len) : env_(env),

                                           read_pos_(0),

                                           write_pos_(0),

                                           len_(len),

                                           next_(nullptr) {

      data_ = new char[len];

      if (env_ != nullptr) {

        env_->external_memory_accounter()->Increase(env_->isolate(), len);

      }

    }

    ~Buffer() {

      delete[] data_;

      if (env_ != nullptr) {

        env_->external_memory_accounter()->Decrease(env_->isolate(), len_);

      }

    }

    Environment* env_;

    size_t read_pos_;

    size_t write_pos_;

    size_t len_;

    Buffer* next_;

    char* data_;

  };

  Environment* env_ = nullptr;

  size_t initial_ = kInitialBufferLength;

  size_t length_ = 0;

  size_t allocate_hint_ = 0;

  int eof_return_ = -1;

  Buffer* read_head_ = nullptr;

  Buffer* write_head_ = nullptr;

};

}  // namespace crypto

}  // namespace node

#endif  // defined(NODE_WANT_INTERNALS) && NODE_WANT_INTERNALS

#endif  // SRC_CRYPTO_CRYPTO_BIO_H_