public:

NodeBIO() : env_(nullptr),

initial_(kInitialBufferLength),

length_(0),

read_head_(nullptr),

write_head_(nullptr) {

}

~NodeBIO();

static BIO* New();

void AssignEnvironment(Environment* env);

// 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 internal data and amount of

// contiguous data available for future writes

char* PeekWritable(size_t* size);

// Commit reserved data

void Commit(size_t size);

// Return size of buffer in bytes

inline size_t Length() const {

return length_;

}

inline void set_initial(size_t initial) {

initial_ = initial;

}

static inline NodeBIO* FromBIO(BIO* bio) {

CHECK_NE(bio->ptr, nullptr);

return static_cast<NodeBIO*>(bio->ptr);

}

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, void* ptr);

// Enough to handle the most of the client hellos

static const size_t kInitialBufferLength = 1024;

static const size_t kThroughputBufferLength = 16384;

static const BIO_METHOD method;

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_->isolate()->AdjustAmountOfExternalAllocatedMemory(len);

}

~Buffer() {

delete[] data_;

if (env_ != nullptr) {

const int64_t len = static_cast<int64_t>(len_);

env_->isolate()->AdjustAmountOfExternalAllocatedMemory(-len);

}

}

Environment* env_;

size_t read_pos_;

size_t write_pos_;

size_t len_;

Buffer* next_;

char* data_;

};

Environment* env_;

size_t initial_;

size_t length_;

Buffer* read_head_;

Buffer* write_head_;