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Build fiddle with WASMFS OPFS support and attempt to use it if available. It does not work because of an inexplicable exception in Emscripten-generated code and perpetually-locked db, but it's not yet clear why.

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FossilOrigin-Name: a16f0a46ec88c560f73d5664e4bf53fb5dd1a22e99a92c11b5c8d784816c3282
This commit is contained in:
stephan
2022-08-12 17:57:09 +00:00
parent 5b0e63eb4c
commit a579f4400d
9 changed files with 303 additions and 227 deletions
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433
ext/wasm/fiddle/fiddle-worker.js
View File

@@ -89,213 +89,230 @@
*/
"use strict";
(function(){
/**
Posts a message in the form {type,data} unless passed more than 2
args, in which case it posts {type, data:[arg1...argN]}.
*/
const wMsg = function(type,data){
postMessage({
type,
data: arguments.length<3
? data
: Array.prototype.slice.call(arguments,1)
});
};
const stdout = function(){wMsg('stdout', Array.prototype.slice.call(arguments));};
const stderr = function(){wMsg('stderr', Array.prototype.slice.call(arguments));};
self.onerror = function(/*message, source, lineno, colno, error*/) {
const err = arguments[4];
if(err && 'ExitStatus'==err.name){
/* This is relevant for the sqlite3 shell binding but not the
lower-level binding. */
fiddleModule.isDead = true;
stderr("FATAL ERROR:", err.message);
stderr("Restarting the app requires reloading the page.");
wMsg('error', err);
}
console.error(err);
fiddleModule.setStatus('Exception thrown, see JavaScript console: '+err);
};
const Sqlite3Shell = {
/** Returns the name of the currently-opened db. */
dbFilename: function f(){
if(!f._) f._ = fiddleModule.cwrap('fiddle_db_filename', "string", ['string']);
return f._();
},
/**
Runs the given text through the shell as if it had been typed
in by a user. Fires a working/start event before it starts and
working/end event when it finishes.
*/
exec: function f(sql){
if(!f._) f._ = fiddleModule.cwrap('fiddle_exec', null, ['string']);
if(fiddleModule.isDead){
stderr("shell module has exit()ed. Cannot run SQL.");
return;
}
wMsg('working','start');
try {
if(f._running){
stderr('Cannot run multiple commands concurrently.');
}else{
f._running = true;
f._(sql);
}
} finally {
delete f._running;
wMsg('working','end');
}
},
resetDb: function f(){
if(!f._) f._ = fiddleModule.cwrap('fiddle_reset_db', null);
stdout("Resetting database.");
f._();
stdout("Reset",this.dbFilename());
},
/* Interrupt can't work: this Worker is tied up working, so won't get the
interrupt event which would be needed to perform the interrupt. */
interrupt: function f(){
if(!f._) f._ = fiddleModule.cwrap('fiddle_interrupt', null);
stdout("Requesting interrupt.");
f._();
}
};
self.onmessage = function f(ev){
ev = ev.data;
if(!f.cache){
f.cache = {
prevFilename: null
};
}
//console.debug("worker: onmessage.data",ev);
switch(ev.type){
case 'shellExec': Sqlite3Shell.exec(ev.data); return;
case 'db-reset': Sqlite3Shell.resetDb(); return;
case 'interrupt': Sqlite3Shell.interrupt(); return;
/** Triggers the export of the current db. Fires an
event in the form:
{type:'db-export',
data:{
filename: name of db,
buffer: contents of the db file (Uint8Array),
error: on error, a message string and no buffer property.
}
}
*/
case 'db-export': {
const fn = Sqlite3Shell.dbFilename();
stdout("Exporting",fn+".");
const fn2 = fn ? fn.split(/[/\\]/).pop() : null;
try{
if(!fn2) throw new Error("DB appears to be closed.");
wMsg('db-export',{
filename: fn2,
buffer: fiddleModule.FS.readFile(fn, {encoding:"binary"})
});
}catch(e){
/* Post a failure message so that UI elements disabled
during the export can be re-enabled. */
wMsg('db-export',{
filename: fn,
error: e.message
});
}
return;
}
case 'open': {
/* Expects: {
buffer: ArrayBuffer | Uint8Array,
filename: for logging/informational purposes only
} */
const opt = ev.data;
let buffer = opt.buffer;
if(buffer instanceof Uint8Array){
}else if(buffer instanceof ArrayBuffer){
buffer = new Uint8Array(buffer);
}else{
stderr("'open' expects {buffer:Uint8Array} containing an uploaded db.");
return;
}
const fn = (
opt.filename
? opt.filename.split(/[/\\]/).pop().replace('"','_')
: ("db-"+((Math.random() * 10000000) | 0)+
"-"+((Math.random() * 10000000) | 0)+".sqlite3")
);
/* We cannot delete the existing db file until the new one
is installed, which means that we risk overflowing our
quota (if any) by having both the previous and current
db briefly installed in the virtual filesystem. */
fiddleModule.FS.createDataFile("/", fn, buffer, true, true);
const oldName = Sqlite3Shell.dbFilename();
Sqlite3Shell.exec('.open "/'+fn+'"');
if(oldName && oldName !== fn){
try{fiddleModule.FS.unlink(oldName);}
catch(e){/*ignored*/}
}
stdout("Replaced DB with",fn+".");
return;
}
};
console.warn("Unknown fiddle-worker message type:",ev);
};
/**
emscripten module for use with build mode -sMODULARIZE.
*/
const fiddleModule = {
print: stdout,
printErr: stderr,
/**
Intercepts status updates from the emscripting module init
and fires worker events with a type of 'status' and a
payload of:
{
text: string | null, // null at end of load process
step: integer // starts at 1, increments 1 per call
}
We have no way of knowing in advance how many steps will
be processed/posted, so creating a "percentage done" view is
not really practical. One can be approximated by giving it a
current value of message.step and max value of message.step+1,
though.
When work is finished, a message with a text value of null is
submitted.
After a message with text==null is posted, the module may later
post messages about fatal problems, e.g. an exit() being
triggered, so it is recommended that UI elements for posting
status messages not be outright removed from the DOM when
text==null, and that they instead be hidden until/unless
text!=null.
*/
setStatus: function f(text){
if(!f.last) f.last = { step: 0, text: '' };
else if(text === f.last.text) return;
f.last.text = text;
wMsg('module',{
type:'status',
data:{step: ++f.last.step, text: text||null}
});
}
};
importScripts('fiddle-module.js');
/**
initFiddleModule() is installed via fiddle-module.js due to
building with:
emcc ... -sMODULARIZE=1 -sEXPORT_NAME=initFiddleModule
*/
initFiddleModule(fiddleModule).then(function(thisModule){
wMsg('fiddle-ready');
/**
Posts a message in the form {type,data} unless passed more than 2
args, in which case it posts {type, data:[arg1...argN]}.
*/
const wMsg = function(type,data){
postMessage({
type,
data: arguments.length<3
? data
: Array.prototype.slice.call(arguments,1)
});
};
const stdout = function(){wMsg('stdout', Array.prototype.slice.call(arguments));};
const stderr = function(){wMsg('stderr', Array.prototype.slice.call(arguments));};
self.onerror = function(/*message, source, lineno, colno, error*/) {
const err = arguments[4];
if(err && 'ExitStatus'==err.name){
/* This is relevant for the sqlite3 shell binding but not the
lower-level binding. */
fiddleModule.isDead = true;
stderr("FATAL ERROR:", err.message);
stderr("Restarting the app requires reloading the page.");
wMsg('error', err);
}
console.error(err);
fiddleModule.setStatus('Exception thrown, see JavaScript console: '+err);
};
const Sqlite3Shell = {
/** Returns the name of the currently-opened db. */
dbFilename: function f(){
if(!f._) f._ = fiddleModule.cwrap('fiddle_db_filename', "string", ['string']);
return f._();
},
/**
Runs the given text through the shell as if it had been typed
in by a user. Fires a working/start event before it starts and
working/end event when it finishes.
*/
exec: function f(sql){
if(!f._) f._ = fiddleModule.cwrap('fiddle_exec', null, ['string']);
if(fiddleModule.isDead){
stderr("shell module has exit()ed. Cannot run SQL.");
return;
}
wMsg('working','start');
try {
if(f._running){
stderr('Cannot run multiple commands concurrently.');
}else{
f._running = true;
f._(sql);
}
} finally {
delete f._running;
wMsg('working','end');
}
},
resetDb: function f(){
if(!f._) f._ = fiddleModule.cwrap('fiddle_reset_db', null);
stdout("Resetting database.");
f._();
stdout("Reset",this.dbFilename());
},
/* Interrupt can't work: this Worker is tied up working, so won't get the
interrupt event which would be needed to perform the interrupt. */
interrupt: function f(){
if(!f._) f._ = fiddleModule.cwrap('fiddle_interrupt', null);
stdout("Requesting interrupt.");
f._();
}
};
self.onmessage = function f(ev){
ev = ev.data;
if(!f.cache){
f.cache = {
prevFilename: null
};
}
//console.debug("worker: onmessage.data",ev);
switch(ev.type){
case 'shellExec': Sqlite3Shell.exec(ev.data); return;
case 'db-reset': Sqlite3Shell.resetDb(); return;
case 'interrupt': Sqlite3Shell.interrupt(); return;
/** Triggers the export of the current db. Fires an
event in the form:
{type:'db-export',
data:{
filename: name of db,
buffer: contents of the db file (Uint8Array),
error: on error, a message string and no buffer property.
}
}
*/
case 'db-export': {
const fn = Sqlite3Shell.dbFilename();
stdout("Exporting",fn+".");
const fn2 = fn ? fn.split(/[/\\]/).pop() : null;
try{
if(!fn2) throw new Error("DB appears to be closed.");
wMsg('db-export',{
filename: fn2,
buffer: fiddleModule.FS.readFile(fn, {encoding:"binary"})
});
}catch(e){
/* Post a failure message so that UI elements disabled
during the export can be re-enabled. */
wMsg('db-export',{
filename: fn,
error: e.message
});
}
return;
}
case 'open': {
/* Expects: {
buffer: ArrayBuffer | Uint8Array,
filename: for logging/informational purposes only
} */
const opt = ev.data;
let buffer = opt.buffer;
if(buffer instanceof Uint8Array){
}else if(buffer instanceof ArrayBuffer){
buffer = new Uint8Array(buffer);
}else{
stderr("'open' expects {buffer:Uint8Array} containing an uploaded db.");
return;
}
const fn = (
opt.filename
? opt.filename.split(/[/\\]/).pop().replace('"','_')
: ("db-"+((Math.random() * 10000000) | 0)+
"-"+((Math.random() * 10000000) | 0)+".sqlite3")
);
/* We cannot delete the existing db file until the new one
is installed, which means that we risk overflowing our
quota (if any) by having both the previous and current
db briefly installed in the virtual filesystem. */
fiddleModule.FS.createDataFile("/", fn, buffer, true, true);
const oldName = Sqlite3Shell.dbFilename();
Sqlite3Shell.exec('.open "/'+fn+'"');
if(oldName && oldName !== fn){
try{fiddleModule.fsUnlink(oldName);}
catch(e){/*ignored*/}
}
stdout("Replaced DB with",fn+".");
return;
}
};
console.warn("Unknown fiddle-worker message type:",ev);
};
/**
emscripten module for use with build mode -sMODULARIZE.
*/
const fiddleModule = {
print: stdout,
printErr: stderr,
/**
Intercepts status updates from the emscripting module init
and fires worker events with a type of 'status' and a
payload of:
{
text: string | null, // null at end of load process
step: integer // starts at 1, increments 1 per call
}
We have no way of knowing in advance how many steps will
be processed/posted, so creating a "percentage done" view is
not really practical. One can be approximated by giving it a
current value of message.step and max value of message.step+1,
though.
When work is finished, a message with a text value of null is
submitted.
After a message with text==null is posted, the module may later
post messages about fatal problems, e.g. an exit() being
triggered, so it is recommended that UI elements for posting
status messages not be outright removed from the DOM when
text==null, and that they instead be hidden until/unless
text!=null.
*/
setStatus: function f(text){
if(!f.last) f.last = { step: 0, text: '' };
else if(text === f.last.text) return;
f.last.text = text;
wMsg('module',{
type:'status',
data:{step: ++f.last.step, text: text||null}
});
}
};
importScripts('fiddle-module.js');
/**
initFiddleModule() is installed via fiddle-module.js due to
building with:
emcc ... -sMODULARIZE=1 -sEXPORT_NAME=initFiddleModule
*/
initFiddleModule(fiddleModule).then(function(thisModule){
fiddleModule.fsUnlink = fiddleModule.cwrap('sqlite3_wasm_vfs_unlink','number',['string']);
(function initOpfs(){
if(!self.FileSystemHandle || !self.FileSystemDirectoryHandle
|| !self.FileSystemFileHandle){
stdout("OPFS unavailable. All DB state is transient.");
return;
}
try {
if(0===fiddleModule.ccall('sqlite3_wasm_init_opfs', undefined)){
stdout("Initialized OPFS WASMFS backend.");
}else{
stderr("Initialization of OPFS WASMFS backend failed.");
}
}catch(e){
stderr("Apparently missing WASMFS:",e.message);
}
})();
wMsg('fiddle-ready');
});
})();