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SyncTERM Font Support Detection

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* Attempt to detect SyncTERM font support using DSR/CPR
* If a terminal doesn't support DSR/CPR, assume it doesn't support SyncTERM fonts, either.
* Support is also disabled if term simply doesn't ignore the ESC sequence, either
This commit is contained in:
Bryan Ashby
2022-04-25 21:09:57 -06:00
parent ac010f2ca4
commit 15c3c87500
5 changed files with 164 additions and 143 deletions
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256
core/connect.js
View File

@@ -12,6 +12,28 @@ const async = require('async');
exports.connectEntry = connectEntry;
const withCursorPositionReport = (client, cprHandler, failMessage, cb) => {
let giveUpTimer;
const done = function(err) {
client.removeListener('cursor position report', cprListener);
clearTimeout(giveUpTimer);
return cb(err);
};
const cprListener = (pos) => {
cprHandler(pos);
return done(null);
};
client.once('cursor position report', cprListener);
// give up after 2s
giveUpTimer = setTimeout( () => {
return done(Errors.General(failMessage));
}, 2000);
}
function ansiDiscoverHomePosition(client, cb) {
//
// We want to find the home position. ANSI-BBS and most terminals
@@ -19,47 +41,34 @@ function ansiDiscoverHomePosition(client, cb) {
// think of home as 0,0. If this is the case, we need to offset
// our positioning to accommodate for such.
//
if( !Config().term.checkAnsiHomePosition ) {
// Skip (and assume 1,1) if the home position check is disabled.
return cb(null);
}
const done = (err) => {
client.removeListener('cursor position report', cprListener);
clearTimeout(giveUpTimer);
return cb(err);
};
withCursorPositionReport(
client,
pos => {
const [h, w] = pos;
const cprListener = function(pos) {
const h = pos[0];
const w = pos[1];
//
// We expect either 0,0, or 1,1. Anything else will be filed as bad data
//
if(h > 1 || w > 1) {
client.log.warn( { height : h, width : w }, 'Ignoring ANSI home position CPR due to unexpected values');
return done(Errors.UnexpectedState('Home position CPR expected to be 0,0, or 1,1'));
}
if(0 === h & 0 === w) {
//
// Store a CPR offset in the client. All CPR's from this point on will offset by this amount
// We expect either 0,0, or 1,1. Anything else will be filed as bad data
//
client.log.info('Setting CPR offset to 1');
client.cprOffset = 1;
}
if(h > 1 || w > 1) {
return client.log.warn( { height : h, width : w }, 'Ignoring ANSI home position CPR due to unexpected values');
}
return done(null);
};
client.once('cursor position report', cprListener);
const giveUpTimer = setTimeout( () => {
return done(Errors.General('Giving up on home position CPR'));
}, 3000); // 3s
if(0 === h & 0 === w) {
//
// Store a CPR offset in the client. All CPR's from this point on will offset by this amount
//
client.log.info('Setting CPR offset to 1');
client.cprOffset = 1;
}
},
'ANSI query home position timed out',
cb
);
client.term.write(`${ansi.goHome()}${ansi.queryPos()}`); // go home, query pos
}
@@ -82,56 +91,74 @@ function ansiAttemptDetectUTF8(client, cb) {
return cb(null);
}
let posStage = 1;
let initialPosition;
let giveUpTimer;
const giveUp = () => {
client.removeListener('cursor position report', cprListener);
clearTimeout(giveUpTimer);
return cb(null);
};
const ASCIIPortion = ' Character encoding detection ';
const cprListener = (pos) => {
switch(posStage) {
case 1 :
posStage = 2;
withCursorPositionReport(
client,
pos => {
initialPosition = pos;
initialPosition = pos;
clearTimeout(giveUpTimer);
giveUpTimer = setTimeout( () => {
return giveUp();
}, 2000);
client.once('cursor position report', cprListener);
client.term.rawWrite(`\u9760${ASCIIPortion}\u9760`); // Unicode skulls on each side
client.term.rawWrite(ansi.queryPos());
break;
case 2 :
{
clearTimeout(giveUpTimer);
const len = pos[1] - initialPosition[1];
withCursorPositionReport(client,
pos => {
const [_, w] = pos;
const len = w - initialPosition[1];
if(!isNaN(len) && len >= ASCIIPortion.length + 6) { // CP437 displays 3 chars each Unicode skull
client.log.info('Terminal identified as UTF-8 but does not appear to be. Overriding to "ansi".');
client.setTermType('ansi');
}
}
return cb(null);
},
'Detect UTF-8 stage 2 timed out',
cb,
);
client.term.rawWrite(`\u9760${ASCIIPortion}\u9760`); // Unicode skulls on each side
client.term.rawWrite(ansi.queryPos());
},
'Detect UTF-8 stage 1 timed out',
err => {
if (err) {
// bailing early
return cb(err);
}
}
};
);
giveUpTimer = setTimeout( () => {
return giveUp();
}, 2000);
client.term.rawWrite(`${ansi.goHome()}${ansi.queryPos()}`);
}
const ansiQuerySyncTermFontSupport = (client, cb) => {
// If we know it's SyncTERM, then good to go
if (client.term.termClient === 'cterm') {
client.term.syncTermFontsEnabled = true;
return cb(null);
}
// Some terminals do not properly ignore an unknown ESC sequence for
// setting SyncTERM style fonts. Some draw only a 'D' while others
// show more of the sequence
//
// If the cursor remains at 1,1, they are at least ignoring it, if not
// supporting it.
//
// We also need CPR support. Since all known terminals that support
// SyncTERM fonts also support CPR, this works out.
//
withCursorPositionReport(
client,
pos => {
const [_, w] = pos;
if (w === 1) {
// cursor didn't move
client.log.info('Client supports SyncTERM fonts or properly ignores unknown ESC sequence');
client.term.syncTermFontsEnabled = true;
}
},
'SyncTERM font detection timed out',
cb
);
client.once('cursor position report', cprListener);
client.term.rawWrite(ansi.goHome() + ansi.queryPos());
client.term.rawWrite(`${ansi.goto(1, 1)}${ansi.setSyncTermFont('cp437')}${ansi.queryPos()}`);
}
function ansiQueryTermSizeIfNeeded(client, cb) {
@@ -139,56 +166,43 @@ function ansiQueryTermSizeIfNeeded(client, cb) {
return cb(null);
}
const done = function(err) {
client.removeListener('cursor position report', cprListener);
clearTimeout(giveUpTimer);
return cb(err);
};
withCursorPositionReport(
client,
pos => {
//
// If we've already found out, disregard
//
if(client.term.termHeight > 0 || client.term.termWidth > 0) {
return;
}
const cprListener = function(pos) {
//
// If we've already found out, disregard
//
if(client.term.termHeight > 0 || client.term.termWidth > 0) {
return done(null);
}
//
// NetRunner for example gives us 1x1 here. Not really useful. Ignore
// values that seem obviously bad. Included in the set is the explicit
// 999x999 values we asked to move to.
//
const [h, w] = pos;
if(h < 10 || h === 999 || w < 10 || w === 999) {
return client.log.warn(
{ height : h, width : w },
'Ignoring ANSI CPR screen size query response due to non-sane values');
}
const h = pos[0];
const w = pos[1];
client.term.termHeight = h;
client.term.termWidth = w;
//
// NetRunner for example gives us 1x1 here. Not really useful. Ignore
// values that seem obviously bad. Included in the set is the explicit
// 999x999 values we asked to move to.
//
if(h < 10 || h === 999 || w < 10 || w === 999) {
client.log.warn(
{ height : h, width : w },
'Ignoring ANSI CPR screen size query response due to non-sane values');
return done(Errors.Invalid('Term size <= 10 considered invalid'));
}
client.term.termHeight = h;
client.term.termWidth = w;
client.log.debug(
{
termWidth : client.term.termWidth,
termHeight : client.term.termHeight,
source : 'ANSI CPR'
},
'Window size updated'
);
return done(null);
};
client.once('cursor position report', cprListener);
// give up after 2s
const giveUpTimer = setTimeout( () => {
return done(Errors.General('No term size established by CPR within timeout'));
}, 2000);
client.log.debug(
{
termWidth : client.term.termWidth,
termHeight : client.term.termHeight,
source : 'ANSI CPR'
},
'Window size updated'
);
},
'No term size established by CPR within timeout',
cb
);
// Start the process:
// 1 - Ask to goto 999,999 -- a very much "bottom right" (generally 80x25 for example
@@ -223,12 +237,11 @@ function connectEntry(client, nextMenu) {
[
function basicPrepWork(callback) {
term.rawWrite(ansi.queryDeviceAttributes(0));
term.write('\nDetecting client features...');
return callback(null);
},
function discoverHomePosition(callback) {
ansiDiscoverHomePosition(client, () => {
return callback(null); // we try to continue anyway
});
return ansiDiscoverHomePosition(client, callback);
},
function queryTermSizeByNonStandardAnsi(callback) {
ansiQueryTermSizeIfNeeded(client, err => {
@@ -254,7 +267,10 @@ function connectEntry(client, nextMenu) {
},
function checkUtf8IfNeeded(callback) {
return ansiAttemptDetectUTF8(client, callback);
}
},
function querySyncTERMFontSupport(callback) {
return ansiQuerySyncTermFontSupport(client, callback);
},
],
() => {
prepareTerminal(term);