web/democode/perlrunner.html

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<title>WebPerl Perl Runner</title>

<!-- ##### WebPerl - http://webperl.zero-g.net #####

Copyright (c) 2018 Hauke Daempfling (haukex@zero-g.net)
at the Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB),
Berlin, Germany, http://www.igb-berlin.de

This program is free software; you can redistribute it and/or modify
it under the same terms as Perl 5 itself: either the GNU General Public
License as published by the Free Software Foundation (either version 1,
or, at your option, any later version), or the "Artistic License" which
comes with Perl 5.

This program is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
See the licenses for details.

You should have received a copy of the licenses along with this program.
If not, see http://perldoc.perl.org/index-licence.html
##### -->

<!-- Please see the documentation on how to use this in demo.html. -->

<!-- Possible To-Do for Later: This whole thing could probably also be
	accomplished with a Web Worker, but that would probably require a
	stripped-down version of webperl.js (that loads things without
	using window.* and especially document.*
	https://developer.mozilla.org/en-US/docs/Web/API/Worker/Worker
	https://developer.mozilla.org/en-US/docs/Web/API/WorkerGlobalScope/importScripts
	
	Of course, at some point I should investigate how difficult it really
	is to re-start an Emscripten program...
	-->

<script src="../webperl.js"></script>
<!--script src="https://webperlcdn.zero-g.net/v0.09-beta/webperl.js"
	integrity="sha256-1RaYAh/WfDl3WZl+BDpSuSycg4x88pfkAFSxhWjBONk=" crossorigin="anonymous"></script-->
<script>
"use strict";

Perl.noMountIdbfs=true; // we're sandboxed
Perl.endAfterMain=true; // act like command-line perl

var knownClients = [];
var currentClient; // which client we're running Perl for, also keeps state
var curOutputFiles;
var stdbuf = [null,'',''];

function reportErr (err) {
	if (currentClient)
		currentClient.postMessage({ perlRunnerError: err },'*');
	else
		console.error(err);
}

Perl.addStateChangeListener(function (from,to) {
	if (to=="Ended" && currentClient) {
		for (var chan=1;chan<=2;chan++) // flush buffers
			if (stdbuf[chan].length) {
				currentClient.postMessage({ perlOutput: { chan:chan, data:stdbuf[chan] } },'*');
				stdbuf[chan] = '';
			}
		currentClient.postMessage({ perlRunnerState: Perl.state,
			exitStatus: Perl.exitStatus },'*');
		for(var i=0; i<knownClients.length; i++)
			if (knownClients[i]!=currentClient)
				knownClients[i].postMessage({ perlRunnerState: Perl.state },'*');
		if (curOutputFiles) {
			var ofs = curOutputFiles.map(function (file) {
				//TODO Later: Support binary files as well?
				// {encoding:"binary"} => readFile returns Uint8Array
				// Should then also provide the same support on FS.writeFile() as well
				var of = { fn: file };
				if (!file) return of;
				try {
					of.text = FS.readFile(file, {encoding:"utf8"});
				}
				catch (e) {
					reportErr("couldn't read "+file+" because "+e);
				}
				return of;
			});
			currentClient.postMessage({ perlOutputFiles: ofs },'*');
		}
	}
	else {
		for(var i=0; i<knownClients.length; i++)
			knownClients[i].postMessage({ perlRunnerState: Perl.state },'*');
	}
	if (to=="Ended") {
		if (!currentClient)
			console.error("Internal Error: Perl state change to Ended with no client");
		window.location.reload(false);
	}
});

Perl.output = function (str,chan) {
	stdbuf[chan] += str;
	var pos = stdbuf[chan].lastIndexOf("\n");
	if (pos<0) return;
	var lines = stdbuf[chan].slice(0,pos+1);
	if (currentClient)
		currentClient.postMessage({ perlOutput: { chan:chan, data:lines } },'*');
	else
		console.error("Internal Error: Output on",chan==1?"STDOUT":"STDERR","with no client:",lines);
	stdbuf[chan] = stdbuf[chan].slice(pos+1);
};

function saveFile (fn, data) {
	if (fn.substring(0,1)!='/') // if relative, make absolute
		fn = FS.joinPath([FS.cwd(), fn]);
	try {
		FS.writeFile(fn, data);
	}
	catch (e) {
		reportErr("couldn't write "+fn+" because "+e);
	}
}

window.addEventListener('message', function (event) {
	if (event.data["perlRunnerDiscovery"]) {
		if (!knownClients.includes(event.source))
			knownClients.push(event.source);
		event.source.postMessage({ perlRunnerState: Perl.state },'*');
	}
	else if (event.data["runPerl"]) {
		if (!knownClients.includes(event.source))
			knownClients.push(event.source);
		// check state
		if (currentClient && currentClient !== event.source) {
			console.error("Attempt to run Perl from",event.source,
				"but am already running Perl for",currentClient);
			reportErr("Attempt to run Perl (from "+event.origin
				+") but am already running Perl for someone else (see JavaScript console)");
			return;
		} // else
		currentClient = event.source;
		if (Perl.state!="Ready") {
			reportErr("Attempt to run Perl in state "+Perl.state);
			return;
		} // else
		// set up files and run perl
		var rp = event.data.runPerl;
		//TODO: we don't check for overlaps in filenames between script+input files (maybe the editor should do that)
		// one solution would be to just have the script be an input file (code mirror syntax highlighting based on filename?)
		// note overlaps of output filenames with input files is ok
		// we also don't check for duplicate filenames
		if (rp["script"])
			saveFile(rp["script_fn"] ? rp.script_fn : 'script.pl', rp.script);
		//TODO Later: can we support STDIN? (probably need to look at webperl.js)
		if (rp["inputs"])
			rp.inputs.forEach(function (inp) {
				if (!inp.fn) return;
				saveFile(inp.fn, inp.text);
			});
		curOutputFiles = rp["outputs"];
		Perl.start( rp["argv"] ? rp.argv : [] );
	}
	else console.warn("Perl Runner ignoring unknown message:", event.data);
});

Perl.init(function () {
	Module['thisProgram'] = 'perl';
	FS.currentPath = ENV.HOME; // NOTE: https://github.com/kripken/emscripten/issues/5873
});

</script>

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