wangle::LineBasedFrameDecoder Class Reference

#include <LineBasedFrameDecoder.h>

Inheritance diagram for wangle::LineBasedFrameDecoder:

Public Types
enum	TerminatorType { TerminatorType::BOTH, TerminatorType::NEWLINE, TerminatorType::CARRIAGENEWLINE }
Public Types inherited from wangle::ByteToMessageDecoder< M >
typedef InboundHandler< folly::IOBufQueue &, M >::Context	Context
Public Types inherited from wangle::InboundHandler< folly::IOBufQueue &, M >
typedef folly::IOBufQueue &	rin
typedef M	rout
typedef folly::Unit	win
typedef folly::Unit	wout
typedef InboundHandlerContext< M >	Context

Public Member Functions
	LineBasedFrameDecoder (uint32_t maxLength=UINT_MAX, bool stripDelimiter=true, TerminatorType terminatorType=TerminatorType::BOTH)
bool	decode (Context *ctx, folly::IOBufQueue &buf, std::unique_ptr< folly::IOBuf > &result, size_t &) override
Public Member Functions inherited from wangle::ByteToMessageDecoder< M >
virtual bool	decode (Context *ctx, folly::IOBufQueue &buf, M &result, size_t &)=0
void	transportActive (Context *ctx) override
void	transportInactive (Context *ctx) override
void	read (Context *ctx, folly::IOBufQueue &q) override
Public Member Functions inherited from wangle::InboundHandler< folly::IOBufQueue &, M >
	~InboundHandler () override=default
virtual void	read (Context *ctx, folly::IOBufQueue &msg)=0
virtual void	readEOF (Context *ctx)
virtual void	readException (Context *ctx, folly::exception_wrapper e)
virtual void	transportActive (Context *ctx)
virtual void	transportInactive (Context *ctx)
Public Member Functions inherited from wangle::HandlerBase< InboundHandlerContext< M > >
virtual	~HandlerBase ()=default
virtual void	attachPipeline (InboundHandlerContext< M > *)
virtual void	detachPipeline (InboundHandlerContext< M > *)
InboundHandlerContext< M > *	getContext ()

Private Member Functions
int64_t	findEndOfLine (folly::IOBufQueue &buf)
void	fail (Context *ctx, std::string len)

Private Attributes
uint32_t	maxLength_
bool	stripDelimiter_
bool	discarding_ {false}
uint32_t	discardedBytes_ {0}
TerminatorType	terminatorType_

Additional Inherited Members
Static Public Attributes inherited from wangle::InboundHandler< folly::IOBufQueue &, M >
static const HandlerDir	dir

Detailed Description

A decoder that splits the received IOBufQueue on line endings.

Both "\n" and "\r\n" are handled, or optionally reqire only one or the other.

Definition at line 30 of file LineBasedFrameDecoder.h.

Member Enumeration Documentation

enum wangle::LineBasedFrameDecoder::TerminatorType

strong

Enumerator
BOTH
NEWLINE
CARRIAGENEWLINE

Definition at line 32 of file LineBasedFrameDecoder.h.

                            {
    BOTH,
    NEWLINE,
    CARRIAGENEWLINE
  };

Constructor & Destructor Documentation

wangle::LineBasedFrameDecoder::LineBasedFrameDecoder ( uint32_t  maxLength = UINT_MAX, bool  stripDelimiter = true, TerminatorType  terminatorType = TerminatorType::BOTH  )

explicit

Definition at line 25 of file LineBasedFrameDecoder.cpp.

    : maxLength_(maxLength)
    , stripDelimiter_(stripDelimiter)
    , terminatorType_(terminatorType) {}

Member Function Documentation

bool wangle::LineBasedFrameDecoder::decode ( Context *  ctx, folly::IOBufQueue &  buf, std::unique_ptr< folly::IOBuf > &  result, size_t &    )

override

Definition at line 32 of file LineBasedFrameDecoder.cpp.

References c, folly::IOBufQueue::chainLength(), discardedBytes_, discarding_, fail(), findEndOfLine(), folly::IOBufQueue::front(), int64_t, maxLength_, folly::IOBufQueue::move(), folly::gen::move, folly::IOBufQueue::split(), stripDelimiter_, and folly::IOBufQueue::trimStart().

                                            {
  int64_t eol = findEndOfLine(buf);

  if (!discarding_) {
    if (eol >= 0) {
      Cursor c(buf.front());
      c += eol;
      auto delimLength = c.read<char>() == '\r' ? 2 : 1;
      if (eol > maxLength_) {
        buf.split(eol + delimLength);
        fail(ctx, folly::to<std::string>(eol));
        return false;
      }

      std::unique_ptr<folly::IOBuf> frame;

      if (stripDelimiter_) {
        frame = buf.split(eol);
        buf.trimStart(delimLength);
      } else {
        frame = buf.split(eol + delimLength);
      }

      result = std::move(frame);
      return true;
    } else {
      auto len = buf.chainLength();
      if (len > maxLength_) {
        discardedBytes_ = len;
        buf.trimStart(len);
        discarding_ = true;
        fail(ctx, "over " + folly::to<std::string>(len));
      }
      return false;
    }
  } else {
    if (eol >= 0) {
      Cursor c(buf.front());
      c += eol;
      auto delimLength = c.read<char>() == '\r' ? 2 : 1;
      buf.trimStart(eol + delimLength);
      discardedBytes_ = 0;
      discarding_ = false;
    } else {
      discardedBytes_ = buf.chainLength();
      buf.move();
    }

    return false;
  }
}

void wangle::LineBasedFrameDecoder::fail ( Context *  ctx, std::string  len  )

private

Definition at line 87 of file LineBasedFrameDecoder.cpp.

References maxLength_.

Referenced by gtest_xml_test_utils.GTestXMLTestCase::_GetChildren(), decode(), and fatal_test.FatalTests::is_debug_build().

                                                            {
  ctx->fireReadException(
    folly::make_exception_wrapper<std::runtime_error>(
      "frame length" + len +
      " exeeds max " + folly::to<std::string>(maxLength_)));
}

int64_t wangle::LineBasedFrameDecoder::findEndOfLine ( folly::IOBufQueue &  buf )

private

Definition at line 94 of file LineBasedFrameDecoder.cpp.

References b, c, CARRIAGENEWLINE, folly::IOBufQueue::chainLength(), folly::IOBufQueue::front(), i, maxLength_, NEWLINE, terminatorType_, and uint32_t.

Referenced by decode().

                                                            {
  Cursor c(buf.front());
  for (uint32_t i = 0; i < maxLength_ && i < buf.chainLength(); i++) {
    auto b = c.read<char>();
    if (b == '\n' && terminatorType_ != TerminatorType::CARRIAGENEWLINE) {
      return i;
    } else if (terminatorType_ != TerminatorType::NEWLINE &&
               b == '\r' && !c.isAtEnd() && c.read<char>() == '\n') {
      return i;
    }
  }

  return -1;
}

Member Data Documentation

uint32_t wangle::LineBasedFrameDecoder::discardedBytes_ {0}

private

Definition at line 58 of file LineBasedFrameDecoder.h.

Referenced by decode().

bool wangle::LineBasedFrameDecoder::discarding_ {false}

private

Definition at line 57 of file LineBasedFrameDecoder.h.

Referenced by decode().

uint32_t wangle::LineBasedFrameDecoder::maxLength_

private

Definition at line 54 of file LineBasedFrameDecoder.h.

Referenced by decode(), fail(), and findEndOfLine().

bool wangle::LineBasedFrameDecoder::stripDelimiter_

private

Definition at line 55 of file LineBasedFrameDecoder.h.

Referenced by decode().

TerminatorType wangle::LineBasedFrameDecoder::terminatorType_

private

Definition at line 60 of file LineBasedFrameDecoder.h.

Referenced by findEndOfLine().

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The documentation for this class was generated from the following files:

• proxygen/wangle/wangle/codec/LineBasedFrameDecoder.h
• proxygen/wangle/wangle/codec/LineBasedFrameDecoder.cpp