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Diffstat (limited to 'testing/xpcshell/node-http2/lib/protocol/stream.js')
| -rw-r--r-- | testing/xpcshell/node-http2/lib/protocol/stream.js | 659 |
1 files changed, 659 insertions, 0 deletions
diff --git a/testing/xpcshell/node-http2/lib/protocol/stream.js b/testing/xpcshell/node-http2/lib/protocol/stream.js new file mode 100644 index 000000000..6d520b949 --- /dev/null +++ b/testing/xpcshell/node-http2/lib/protocol/stream.js @@ -0,0 +1,659 @@ +var assert = require('assert'); + +// The Stream class +// ================ + +// Stream is a [Duplex stream](https://nodejs.org/api/stream.html#stream_class_stream_duplex) +// subclass that implements the [HTTP/2 Stream](https://tools.ietf.org/html/rfc7540#section-5) +// concept. It has two 'sides': one that is used by the user to send/receive data (the `stream` +// object itself) and one that is used by a Connection to read/write frames to/from the other peer +// (`stream.upstream`). + +var Duplex = require('stream').Duplex; + +exports.Stream = Stream; + +// Public API +// ---------- + +// * **new Stream(log, connection)**: create a new Stream +// +// * **Event: 'headers' (headers)**: signals incoming headers +// +// * **Event: 'promise' (stream, headers)**: signals an incoming push promise +// +// * **Event: 'priority' (priority)**: signals a priority change. `priority` is a number between 0 +// (highest priority) and 2^31-1 (lowest priority). Default value is 2^30. +// +// * **Event: 'error' (type)**: signals an error +// +// * **headers(headers)**: send headers +// +// * **promise(headers): Stream**: promise a stream +// +// * **priority(priority)**: set the priority of the stream. Priority can be changed by the peer +// too, but once it is set locally, it can not be changed remotely. +// +// * **reset(error)**: reset the stream with an error code +// +// * **upstream**: a [Flow](flow.js) that is used by the parent connection to write/read frames +// that are to be sent/arrived to/from the peer and are related to this stream. +// +// Headers are always in the [regular node.js header format][1]. +// [1]: https://nodejs.org/api/http.html#http_message_headers + +// Constructor +// ----------- + +// The main aspects of managing the stream are: +function Stream(log, connection) { + Duplex.call(this); + + // * logging + this._log = log.child({ component: 'stream', s: this }); + + // * receiving and sending stream management commands + this._initializeManagement(); + + // * sending and receiving frames to/from the upstream connection + this._initializeDataFlow(); + + // * maintaining the state of the stream (idle, open, closed, etc.) and error detection + this._initializeState(); + + this.connection = connection; +} + +Stream.prototype = Object.create(Duplex.prototype, { constructor: { value: Stream } }); + +// Managing the stream +// ------------------- + +// the default stream priority is 2^30 +var DEFAULT_PRIORITY = Math.pow(2, 30); +var MAX_PRIORITY = Math.pow(2, 31) - 1; + +// PUSH_PROMISE and HEADERS are forwarded to the user through events. +Stream.prototype._initializeManagement = function _initializeManagement() { + this._resetSent = false; + this._priority = DEFAULT_PRIORITY; + this._letPeerPrioritize = true; +}; + +Stream.prototype.promise = function promise(headers) { + var stream = new Stream(this._log, this.connection); + stream._priority = Math.min(this._priority + 1, MAX_PRIORITY); + this._pushUpstream({ + type: 'PUSH_PROMISE', + flags: {}, + stream: this.id, + promised_stream: stream, + headers: headers + }); + return stream; +}; + +Stream.prototype._onPromise = function _onPromise(frame) { + this.emit('promise', frame.promised_stream, frame.headers); +}; + +Stream.prototype.headers = function headers(headers) { + this._pushUpstream({ + type: 'HEADERS', + flags: {}, + stream: this.id, + headers: headers + }); +}; + +Stream.prototype._onHeaders = function _onHeaders(frame) { + if (frame.priority !== undefined) { + this.priority(frame.priority, true); + } + this.emit('headers', frame.headers); +}; + +Stream.prototype.priority = function priority(priority, peer) { + if ((peer && this._letPeerPrioritize) || !peer) { + if (!peer) { + this._letPeerPrioritize = false; + + var lastFrame = this.upstream.getLastQueuedFrame(); + if (lastFrame && ((lastFrame.type === 'HEADERS') || (lastFrame.type === 'PRIORITY'))) { + lastFrame.priority = priority; + } else { + this._pushUpstream({ + type: 'PRIORITY', + flags: {}, + stream: this.id, + priority: priority + }); + } + } + + this._log.debug({ priority: priority }, 'Changing priority'); + this.emit('priority', priority); + this._priority = priority; + } +}; + +Stream.prototype._onPriority = function _onPriority(frame) { + this.priority(frame.priority, true); +}; + +// Resetting the stream. Normally, an endpoint SHOULD NOT send more than one RST_STREAM frame for +// any stream. +Stream.prototype.reset = function reset(error) { + if (!this._resetSent) { + this._resetSent = true; + this._pushUpstream({ + type: 'RST_STREAM', + flags: {}, + stream: this.id, + error: error + }); + } +}; + +// Specify an alternate service for the origin of this stream +Stream.prototype.altsvc = function altsvc(host, port, protocolID, maxAge, origin) { + var stream; + if (origin) { + stream = 0; + } else { + stream = this.id; + } + this._pushUpstream({ + type: 'ALTSVC', + flags: {}, + stream: stream, + host: host, + port: port, + protocolID: protocolID, + origin: origin, + maxAge: maxAge + }); +}; + +// Data flow +// --------- + +// The incoming and the generated outgoing frames are received/transmitted on the `this.upstream` +// [Flow](flow.html). The [Connection](connection.html) object instantiating the stream will read +// and write frames to/from it. The stream itself is a regular [Duplex stream][1], and is used by +// the user to write or read the body of the request. +// [1]: https://nodejs.org/api/stream.html#stream_class_stream_duplex + +// upstream side stream user side +// +// +------------------------------------+ +// | | +// +------------------+ | +// | upstream | | +// | | | +// +--+ | +--| +// read() | | _send() | _write() | | write(buf) +// <--------------|B |<--------------|--------------| B|<------------ +// | | | | | +// frames +--+ | +--| buffers +// | | | | | +// -------------->|B |---------------|------------->| B|------------> +// write(frame) | | _receive() | _read() | | read() +// +--+ | +--| +// | | | +// | | | +// +------------------+ | +// | | +// +------------------------------------+ +// +// B: input or output buffer + +var Flow = require('./flow').Flow; + +Stream.prototype._initializeDataFlow = function _initializeDataFlow() { + this.id = undefined; + + this._ended = false; + + this.upstream = new Flow(); + this.upstream._log = this._log; + this.upstream._send = this._send.bind(this); + this.upstream._receive = this._receive.bind(this); + this.upstream.write = this._writeUpstream.bind(this); + this.upstream.on('error', this.emit.bind(this, 'error')); + + this.on('finish', this._finishing); +}; + +Stream.prototype._pushUpstream = function _pushUpstream(frame) { + this.upstream.push(frame); + this._transition(true, frame); +}; + +// Overriding the upstream's `write` allows us to act immediately instead of waiting for the input +// queue to empty. This is important in case of control frames. +Stream.prototype._writeUpstream = function _writeUpstream(frame) { + this._log.debug({ frame: frame }, 'Receiving frame'); + + var moreNeeded = Flow.prototype.write.call(this.upstream, frame); + + // * Transition to a new state if that's the effect of receiving the frame + this._transition(false, frame); + + // * If it's a control frame. Call the appropriate handler method. + if (frame.type === 'HEADERS') { + if (this._processedHeaders && !frame.flags['END_STREAM']) { + this.emit('error', 'PROTOCOL_ERROR'); + } + this._processedHeaders = true; + this._onHeaders(frame); + } else if (frame.type === 'PUSH_PROMISE') { + this._onPromise(frame); + } else if (frame.type === 'PRIORITY') { + this._onPriority(frame); + } else if (frame.type === 'ALTSVC') { + // TODO + } else if (frame.type === 'BLOCKED') { + // TODO + } + + // * If it's an invalid stream level frame, emit error + else if ((frame.type !== 'DATA') && + (frame.type !== 'WINDOW_UPDATE') && + (frame.type !== 'RST_STREAM')) { + this._log.error({ frame: frame }, 'Invalid stream level frame'); + this.emit('error', 'PROTOCOL_ERROR'); + } + + return moreNeeded; +}; + +// The `_receive` method (= `upstream._receive`) gets called when there's an incoming frame. +Stream.prototype._receive = function _receive(frame, ready) { + // * If it's a DATA frame, then push the payload into the output buffer on the other side. + // Call ready when the other side is ready to receive more. + if (!this._ended && (frame.type === 'DATA')) { + var moreNeeded = this.push(frame.data); + if (!moreNeeded) { + this._receiveMore = ready; + } + } + + // * Any frame may signal the end of the stream with the END_STREAM flag + if (!this._ended && (frame.flags.END_STREAM || (frame.type === 'RST_STREAM'))) { + this.push(null); + this._ended = true; + } + + // * Postpone calling `ready` if `push()` returned a falsy value + if (this._receiveMore !== ready) { + ready(); + } +}; + +// The `_read` method is called when the user side is ready to receive more data. If there's a +// pending write on the upstream, then call its pending ready callback to receive more frames. +Stream.prototype._read = function _read() { + if (this._receiveMore) { + var receiveMore = this._receiveMore; + delete this._receiveMore; + receiveMore(); + } +}; + +// The `write` method gets called when there's a write request from the user. +Stream.prototype._write = function _write(buffer, encoding, ready) { + // * Chunking is done by the upstream Flow. + var moreNeeded = this._pushUpstream({ + type: 'DATA', + flags: {}, + stream: this.id, + data: buffer + }); + + // * Call ready when upstream is ready to receive more frames. + if (moreNeeded) { + ready(); + } else { + this._sendMore = ready; + } +}; + +// The `_send` (= `upstream._send`) method is called when upstream is ready to receive more frames. +// If there's a pending write on the user side, then call its pending ready callback to receive more +// writes. +Stream.prototype._send = function _send() { + if (this._sendMore) { + var sendMore = this._sendMore; + delete this._sendMore; + sendMore(); + } +}; + +// When the stream is finishing (the user calls `end()` on it), then we have to set the `END_STREAM` +// flag on the last frame. If there's no frame in the queue, or if it doesn't support this flag, +// then we create a 0 length DATA frame. We could do this all the time, but putting the flag on an +// existing frame is a nice optimization. +var emptyBuffer = new Buffer(0); +Stream.prototype._finishing = function _finishing() { + var endFrame = { + type: 'DATA', + flags: { END_STREAM: true }, + stream: this.id, + data: emptyBuffer + }; + var lastFrame = this.upstream.getLastQueuedFrame(); + if (lastFrame && ((lastFrame.type === 'DATA') || (lastFrame.type === 'HEADERS'))) { + this._log.debug({ frame: lastFrame }, 'Marking last frame with END_STREAM flag.'); + lastFrame.flags.END_STREAM = true; + this._transition(true, endFrame); + } else { + this._pushUpstream(endFrame); + } +}; + +// [Stream States](https://tools.ietf.org/html/rfc7540#section-5.1) +// ---------------- +// +// +--------+ +// PP | | PP +// ,--------| idle |--------. +// / | | \ +// v +--------+ v +// +----------+ | +----------+ +// | | | H | | +// ,---| reserved | | | reserved |---. +// | | (local) | v | (remote) | | +// | +----------+ +--------+ +----------+ | +// | | ES | | ES | | +// | | H ,-------| open |-------. | H | +// | | / | | \ | | +// | v v +--------+ v v | +// | +----------+ | +----------+ | +// | | half | | | half | | +// | | closed | | R | closed | | +// | | (remote) | | | (local) | | +// | +----------+ | +----------+ | +// | | v | | +// | | ES / R +--------+ ES / R | | +// | `----------->| |<-----------' | +// | R | closed | R | +// `-------------------->| |<--------------------' +// +--------+ + +// Streams begin in the IDLE state and transitions happen when there's an incoming or outgoing frame +Stream.prototype._initializeState = function _initializeState() { + this.state = 'IDLE'; + this._initiated = undefined; + this._closedByUs = undefined; + this._closedWithRst = undefined; + this._processedHeaders = false; +}; + +// Only `_setState` should change `this.state` directly. It also logs the state change and notifies +// interested parties using the 'state' event. +Stream.prototype._setState = function transition(state) { + assert(this.state !== state); + this._log.debug({ from: this.state, to: state }, 'State transition'); + this.state = state; + this.emit('state', state); +}; + +// A state is 'active' if the stream in that state counts towards the concurrency limit. Streams +// that are in the "open" state, or either of the "half closed" states count toward this limit. +function activeState(state) { + return ((state === 'HALF_CLOSED_LOCAL') || (state === 'HALF_CLOSED_REMOTE') || (state === 'OPEN')); +} + +// `_transition` is called every time there's an incoming or outgoing frame. It manages state +// transitions, and detects stream errors. A stream error is always caused by a frame that is not +// allowed in the current state. +Stream.prototype._transition = function transition(sending, frame) { + var receiving = !sending; + var connectionError; + var streamError; + + var DATA = false, HEADERS = false, PRIORITY = false, ALTSVC = false, BLOCKED = false; + var RST_STREAM = false, PUSH_PROMISE = false, WINDOW_UPDATE = false; + switch(frame.type) { + case 'DATA' : DATA = true; break; + case 'HEADERS' : HEADERS = true; break; + case 'PRIORITY' : PRIORITY = true; break; + case 'RST_STREAM' : RST_STREAM = true; break; + case 'PUSH_PROMISE' : PUSH_PROMISE = true; break; + case 'WINDOW_UPDATE': WINDOW_UPDATE = true; break; + case 'ALTSVC' : ALTSVC = true; break; + case 'BLOCKED' : BLOCKED = true; break; + } + + var previousState = this.state; + + switch (this.state) { + // All streams start in the **idle** state. In this state, no frames have been exchanged. + // + // * Sending or receiving a HEADERS frame causes the stream to become "open". + // + // When the HEADERS frame contains the END_STREAM flags, then two state transitions happen. + case 'IDLE': + if (HEADERS) { + this._setState('OPEN'); + if (frame.flags.END_STREAM) { + this._setState(sending ? 'HALF_CLOSED_LOCAL' : 'HALF_CLOSED_REMOTE'); + } + this._initiated = sending; + } else if (sending && RST_STREAM) { + this._setState('CLOSED'); + } else if (PRIORITY) { + /* No state change */ + } else { + connectionError = 'PROTOCOL_ERROR'; + } + break; + + // A stream in the **reserved (local)** state is one that has been promised by sending a + // PUSH_PROMISE frame. + // + // * The endpoint can send a HEADERS frame. This causes the stream to open in a "half closed + // (remote)" state. + // * Either endpoint can send a RST_STREAM frame to cause the stream to become "closed". This + // releases the stream reservation. + // * An endpoint may receive PRIORITY frame in this state. + // * An endpoint MUST NOT send any other type of frame in this state. + case 'RESERVED_LOCAL': + if (sending && HEADERS) { + this._setState('HALF_CLOSED_REMOTE'); + } else if (RST_STREAM) { + this._setState('CLOSED'); + } else if (PRIORITY) { + /* No state change */ + } else { + connectionError = 'PROTOCOL_ERROR'; + } + break; + + // A stream in the **reserved (remote)** state has been reserved by a remote peer. + // + // * Either endpoint can send a RST_STREAM frame to cause the stream to become "closed". This + // releases the stream reservation. + // * Receiving a HEADERS frame causes the stream to transition to "half closed (local)". + // * An endpoint MAY send PRIORITY frames in this state to reprioritize the stream. + // * Receiving any other type of frame MUST be treated as a stream error of type PROTOCOL_ERROR. + case 'RESERVED_REMOTE': + if (RST_STREAM) { + this._setState('CLOSED'); + } else if (receiving && HEADERS) { + this._setState('HALF_CLOSED_LOCAL'); + } else if (BLOCKED || PRIORITY) { + /* No state change */ + } else { + connectionError = 'PROTOCOL_ERROR'; + } + break; + + // The **open** state is where both peers can send frames. In this state, sending peers observe + // advertised stream level flow control limits. + // + // * From this state either endpoint can send a frame with a END_STREAM flag set, which causes + // the stream to transition into one of the "half closed" states: an endpoint sending a + // END_STREAM flag causes the stream state to become "half closed (local)"; an endpoint + // receiving a END_STREAM flag causes the stream state to become "half closed (remote)". + // * Either endpoint can send a RST_STREAM frame from this state, causing it to transition + // immediately to "closed". + case 'OPEN': + if (frame.flags.END_STREAM) { + this._setState(sending ? 'HALF_CLOSED_LOCAL' : 'HALF_CLOSED_REMOTE'); + } else if (RST_STREAM) { + this._setState('CLOSED'); + } else { + /* No state change */ + } + break; + + // A stream that is **half closed (local)** cannot be used for sending frames. + // + // * A stream transitions from this state to "closed" when a frame that contains a END_STREAM + // flag is received, or when either peer sends a RST_STREAM frame. + // * An endpoint MAY send or receive PRIORITY frames in this state to reprioritize the stream. + // * WINDOW_UPDATE can be sent by a peer that has sent a frame bearing the END_STREAM flag. + case 'HALF_CLOSED_LOCAL': + if (RST_STREAM || (receiving && frame.flags.END_STREAM)) { + this._setState('CLOSED'); + } else if (BLOCKED || ALTSVC || receiving || PRIORITY || (sending && WINDOW_UPDATE)) { + /* No state change */ + } else { + connectionError = 'PROTOCOL_ERROR'; + } + break; + + // A stream that is **half closed (remote)** is no longer being used by the peer to send frames. + // In this state, an endpoint is no longer obligated to maintain a receiver flow control window + // if it performs flow control. + // + // * If an endpoint receives additional frames for a stream that is in this state it MUST + // respond with a stream error of type STREAM_CLOSED. + // * A stream can transition from this state to "closed" by sending a frame that contains a + // END_STREAM flag, or when either peer sends a RST_STREAM frame. + // * An endpoint MAY send or receive PRIORITY frames in this state to reprioritize the stream. + // * A receiver MAY receive a WINDOW_UPDATE frame on a "half closed (remote)" stream. + case 'HALF_CLOSED_REMOTE': + if (RST_STREAM || (sending && frame.flags.END_STREAM)) { + this._setState('CLOSED'); + } else if (BLOCKED || ALTSVC || sending || PRIORITY || (receiving && WINDOW_UPDATE)) { + /* No state change */ + } else { + connectionError = 'PROTOCOL_ERROR'; + } + break; + + // The **closed** state is the terminal state. + // + // * An endpoint MUST NOT send frames on a closed stream. An endpoint that receives a frame + // after receiving a RST_STREAM or a frame containing a END_STREAM flag on that stream MUST + // treat that as a stream error of type STREAM_CLOSED. + // * WINDOW_UPDATE, PRIORITY or RST_STREAM frames can be received in this state for a short + // period after a frame containing an END_STREAM flag is sent. Until the remote peer receives + // and processes the frame bearing the END_STREAM flag, it might send either frame type. + // Endpoints MUST ignore WINDOW_UPDATE frames received in this state, though endpoints MAY + // choose to treat WINDOW_UPDATE frames that arrive a significant time after sending + // END_STREAM as a connection error of type PROTOCOL_ERROR. + // * If this state is reached as a result of sending a RST_STREAM frame, the peer that receives + // the RST_STREAM might have already sent - or enqueued for sending - frames on the stream + // that cannot be withdrawn. An endpoint that sends a RST_STREAM frame MUST ignore frames that + // it receives on closed streams after it has sent a RST_STREAM frame. An endpoint MAY choose + // to limit the period over which it ignores frames and treat frames that arrive after this + // time as being in error. + // * An endpoint might receive a PUSH_PROMISE frame after it sends RST_STREAM. PUSH_PROMISE + // causes a stream to become "reserved". If promised streams are not desired, a RST_STREAM + // can be used to close any of those streams. + case 'CLOSED': + if (PRIORITY || (sending && RST_STREAM) || + (receiving && WINDOW_UPDATE) || + (receiving && this._closedByUs && + (this._closedWithRst || RST_STREAM || ALTSVC))) { + /* No state change */ + } else { + streamError = 'STREAM_CLOSED'; + } + break; + } + + // Noting that the connection was closed by the other endpoint. It may be important in edge cases. + // For example, when the peer tries to cancel a promised stream, but we already sent every data + // on it, then the stream is in CLOSED state, yet we want to ignore the incoming RST_STREAM. + if ((this.state === 'CLOSED') && (previousState !== 'CLOSED')) { + this._closedByUs = sending; + this._closedWithRst = RST_STREAM; + } + + // Sending/receiving a PUSH_PROMISE + // + // * Sending a PUSH_PROMISE frame marks the associated stream for later use. The stream state + // for the reserved stream transitions to "reserved (local)". + // * Receiving a PUSH_PROMISE frame marks the associated stream as reserved by the remote peer. + // The state of the stream becomes "reserved (remote)". + if (PUSH_PROMISE && !connectionError && !streamError) { + /* This assertion must hold, because _transition is called immediately when a frame is written + to the stream. If it would be called when a frame gets out of the input queue, the state + of the reserved could have been changed by then. */ + assert(frame.promised_stream.state === 'IDLE', frame.promised_stream.state); + frame.promised_stream._setState(sending ? 'RESERVED_LOCAL' : 'RESERVED_REMOTE'); + frame.promised_stream._initiated = sending; + } + + // Signaling how sending/receiving this frame changes the active stream count (-1, 0 or +1) + if (this._initiated) { + var change = (activeState(this.state) - activeState(previousState)); + if (sending) { + frame.count_change = change; + } else { + frame.count_change(change); + } + } else if (sending) { + frame.count_change = 0; + } + + // Common error handling. + if (connectionError || streamError) { + var info = { + error: connectionError, + frame: frame, + state: this.state, + closedByUs: this._closedByUs, + closedWithRst: this._closedWithRst + }; + + // * When sending something invalid, throwing an exception, since it is probably a bug. + if (sending) { + this._log.error(info, 'Sending illegal frame.'); + return this.emit('error', new Error('Sending illegal frame (' + frame.type + ') in ' + this.state + ' state.')); + } + + // * In case of a serious problem, emitting and error and letting someone else handle it + // (e.g. closing the connection) + // * When receiving something invalid, sending an RST_STREAM using the `reset` method. + // This will automatically cause a transition to the CLOSED state. + else { + this._log.error(info, 'Received illegal frame.'); + if (connectionError) { + this.emit('connectionError', connectionError); + } else { + this.reset(streamError); + this.emit('error', streamError); + } + } + } +}; + +// Bunyan serializers +// ------------------ + +exports.serializers = {}; + +var nextId = 0; +exports.serializers.s = function(stream) { + if (!('_id' in stream)) { + stream._id = nextId; + nextId += 1; + } + return stream._id; +}; |