waveterm/xterm.js
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Add write buffer pause and refresh frame skip

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Daniel Imms
2017-01-03 15:26:41 -08:00
parent 6b8c43ed7f
commit e66b1c5704
1 changed files with 69 additions and 35 deletions
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src/xterm.js
+69 -35
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@@ -37,6 +37,19 @@ var document = (typeof window != 'undefined') ? window.document : null;
*/
var normal = 0, escaped = 1, csi = 2, osc = 3, charset = 4, dcs = 5, ignore = 6;
/**
* The amount of write requests to queue before sending an XOFF signal to the
* pty process. This number must be small in order for ^C and similar sequences
* to be responsive.
*/
var WRITE_BUFFER_PAUSE_THRESHOLD = 0;
/**
* The maximum number of refresh frames to skip when the write buffer is non-
* empty.
*/
var MAX_REFRESH_FRAME_SKIP = 6;
/**
* Terminal
*/
@@ -199,7 +212,18 @@ function Terminal(options) {
// user input states
this.writeBuffer = [];
this.writeInProgress = false;
this.user_xoff = false; // user pressed XOFF
this.refreshFramesSkipped = 0;
/**
* Whether _xterm.js_ sent XOFF in order to catch up with the pty process.
* This is a distinct state from writeStopped so that if the user requested
* XOFF via ^S that it will not automatically resume when the writeBuffer goes
* below threshold.
*/
this.xoffSentToCatchUp = false;
/** Whether writing has been stopped as a result of XOFF */
this.writeStopped = false;
// leftover surrogate high from previous write invocation
this.surrogate_high = '';
@@ -1014,27 +1038,36 @@ Terminal.prototype.queueRefresh = function(start, end) {
Terminal.prototype.refreshLoop = function() {
// Don't refresh if there were no row changes
if (this.refreshRowsQueue.length > 0) {
var start;
var end;
if (this.refreshRowsQueue.length > 4) {
// Just do a full refresh when 5+ refreshes are queued
start = 0;
end = this.rows - 1;
} else {
// Get start and end rows that need refreshing
start = this.refreshRowsQueue[0].start;
end = this.refreshRowsQueue[0].end;
for (var i = 1; i < this.refreshRowsQueue.length; i++) {
if (this.refreshRowsQueue[i].start < start) {
start = this.refreshRowsQueue[i].start;
}
if (this.refreshRowsQueue[i].end > end) {
end = this.refreshRowsQueue[i].end;
// Skip MAX_REFRESH_FRAME_SKIP frames if the writeBuffer is non-empty as it
// will need to be immediately refreshed anyway. This saves a lot of
// rendering time as the viewport DOM does not need to be refreshed, no
// scroll events, no layouts, etc.
var skipFrame = this.writeBuffer.length > 0 && this.refreshFramesSkipped++ <= MAX_REFRESH_FRAME_SKIP;
if (!skipFrame) {
this.refreshFramesSkipped = 0;
var start;
var end;
if (this.refreshRowsQueue.length > 4) {
// Just do a full refresh when 5+ refreshes are queued
start = 0;
end = this.rows - 1;
} else {
// Get start and end rows that need refreshing
start = this.refreshRowsQueue[0].start;
end = this.refreshRowsQueue[0].end;
for (var i = 1; i < this.refreshRowsQueue.length; i++) {
if (this.refreshRowsQueue[i].start < start) {
start = this.refreshRowsQueue[i].start;
}
if (this.refreshRowsQueue[i].end > end) {
end = this.refreshRowsQueue[i].end;
}
}
}
this.refreshRowsQueue = [];
this.refresh(start, end);
}
this.refreshRowsQueue = [];
this.refresh(start, end);
}
window.requestAnimationFrame(this.refreshLoop.bind(this));
}
@@ -1348,11 +1381,14 @@ Terminal.prototype.scrollToBottom = function() {
Terminal.prototype.write = function(data) {
this.writeBuffer.push(data);
// Pause pty process if the write buffer becomes too large so xterm.js can catch up
if (this.writeBuffer.length > 1000 && !this.user_xoff) {
// Send XOFF to pause the pty process if the write buffer becomes too large so
// xterm.js can catch up before more data is sent. This is necessary in order
// to keep signals such as ^C responsive.
if (!this.xoffSentToCatchUp && this.writeBuffer.length > WRITE_BUFFER_PAUSE_THRESHOLD) {
// XOFF - stop pty pipe
// XON will be triggered by emulator before processing data chunk
this.send('\x13');
this.xoffSentToCatchUp = true;
}
if (!this.writeInProgress && this.writeBuffer.length > 0) {
@@ -1368,17 +1404,12 @@ Terminal.prototype.write = function(data) {
Terminal.prototype.innerWrite = function(data) {
var l = data.length, i = 0, j, cs, ch, code, low, ch_width, row;
console.log('writeBuffer length: ' + this.writeBuffer.length);
// TODO: Need to have another buffer where data is held where write can grab lines from
// When this hits a certain threshold it should send this.write('\x13')
// XON - about to process data, thus we can get more
// dont lift XOFF if user pressed it
if (!this.user_xoff) {
// Resume pty process to get more data
if (this.writeBuffer.length < 200) {
this.send('\x11');
}
// If XOFF was sent in order to catch up with the pty process, resume it if
// the writeBuffer is empty to allow more data to come in.
if (this.xoffSentToCatchUp && this.writeBuffer.length === 0) {
this.send('\x11');
this.xoffSentToCatchUp = false;
}
this.refreshStart = this.y;
@@ -2421,10 +2452,13 @@ console.log('writeBuffer length: ' + this.writeBuffer.length);
if (this.writeBuffer.length > 0) {
var self = this;
// TODO: async makes this too slow, need to change to iterative to prevent potential stack overflow
// Start a new async innerWrite to prevent a stack overflow
setTimeout(function () {
//setTimeout(function () {
self.innerWrite(self.writeBuffer.shift());
});
//});
} else {
this.writeInProgress = false;
}
@@ -2472,9 +2506,9 @@ Terminal.prototype.keyDown = function(ev) {
var result = this.evaluateKeyEscapeSequence(ev);
if (result.key === '\x13') { // XOFF
this.user_xoff = true;
this.writeStopped = true;
} else if (result.key === '\x11') { // XON
this.user_xoff = false;
this.writeStopped = false;
}
if (result.scrollDisp) {