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IndexedDB is now used as a cache for game files
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Emularity had been storing downloaded game files into the IndexedDB,
but if the file was already present then it would download it again
and overwrite it. Now it will skip the download if the file exists.

At present this only applies to files downloaded using the “saveFile”
method, not the “mountZip” method. The “mountZip” method doesn’t save
the zip file anywhere, so no caching is currently done.

Potentially this could cause you problems if a file gets corrupted or
edited, and reloading the page won’t fix it. Emularity doesn‘t provide
a UI for diagnosing or fixing such problems at present, so you may
want to implement some way to flush the IndexedDB containing the
filesystem.
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@db48x
db48x committed Jan 4, 2022
1 parent c66ae61 commit d6547c5
Showing 1 changed file with 133 additions and 115 deletions.
248 changes: 133 additions & 115 deletions loader.js
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Original file line number Diff line number Diff line change
Expand Up @@ -1496,82 +1496,87 @@ var Module = null;
// deltaFS, letting us mount read-only zip files into the MountableFileSystem
// while being able to "write" to them.
var MountableFS = BrowserFS.FileSystem.MountableFileSystem,
OverlayFS = BrowserFS.FileSystem.OverlayFS;
InMemoryFS.Create(function (e, inMemory) {
MountableFS.Create(function (e, mountable) {
OverlayFS.Create({ readable: mountable
, writable: deltaFS
},
function (e, fs) {
if (e) {
console.error("Failed to initialize the OverlayFS:", e);
reject();
} else {
game_data.fs = fs;
var Buffer = BrowserFS.BFSRequire('buffer').Buffer;
function fetch(file) {
if ('data' in file && file.data !== null && typeof file.data !== 'undefined') {
return Promise.resolve(file.data);
}
OverlayFS = BrowserFS.FileSystem.OverlayFS,
ZipFS = BrowserFS.FileSystem.ZipFS,
Buffer = BrowserFS.BFSRequire('buffer').Buffer;
MountableFS.Create(function (e, mountable) {
OverlayFS.Create({ readable: mountable
, writable: deltaFS
},
function (e, fs) {
if (e) {
console.error("Failed to initialize the OverlayFS:", e);
reject();
} else {
game_data.fs = fs;
function fetch(file) {
var isCached = 'cached' in file && file.cached,
hasData = 'data' in file && file.data !== null && typeof file.data !== 'undefined';
if (isCached || hasData) {
return cached_file(file.title, file.data);
} else {
return fetch_file(file.title, file.url, 'arraybuffer', file.optional);
}
function mountat(drive) {
return function (data) {
if (data !== null) {
drive = drive.toLowerCase();
var mountpoint = '/'+ drive;
// Mount into RO MFS.
return new Promise(function (resolve, reject) {
var ZipFS = BrowserFS.FileSystem.ZipFS;
return new ZipFS.Create({ zipData: new Buffer(data) },
function (e, fs) {
if (e) {
reject();
} else {
game_data.fs.getOverlayedFileSystems().readable.mount(mountpoint, fs);
resolve();
}
});
});
}
function mountat(drive) {
return function (data) {
if (data !== null) {
drive = drive.toLowerCase();
var mountpoint = '/'+ drive;
// Mount into RO MFS.
return new Promise(function (resolve, reject) {
return new ZipFS.Create({ zipData: new Buffer(data) },
function (e, fs) {
if (e) {
reject();
} else {
mountable.mount(mountpoint, fs);
resolve();
}
});
});
}
};
}
function saveat(filename) {
return function (data) {
if (data !== null) {
if (deltaFS.existsSync(filename)) {
return;
}
};
}
function saveat(filename) {
return function (data) {
if (data !== null) {
if (filename.includes('/')) {
var parts = filename.split('/');
for (var i = 1; i < parts.length; i++) {
var path = '/'+ parts.slice(0, i).join('/');
if (!mountable.existsSync(path)) {
mountable.mkdirSync(path);
}
if (filename.includes('/', 1)) {
var parts = filename.substring(1).split('/');
for (var i = 1; i < parts.length; i++) {
var path = '/'+ parts.slice(0, i).join('/');
if (!deltaFS.existsSync(path)) {
deltaFS.mkdirSync(path, 0777);
}
}
mountable.writeFileSync('/'+ filename, new Buffer(data), null, flag_w, 0x1a4);
}
};
}

var promises = game_data.files
.map(function (f) {
if (f && f.file) {
if (f.drive) {
return fetch(f.file).then(mountat(f.drive));
} else if (f.mountpoint) {
return fetch(f.file).then(saveat(f.mountpoint));
}
deltaFS.writeFileSync(filename, new Buffer(data), null, flag_w, 0644);
}
};
}
var promises = game_data.files
.map(function (f) {
if (f && f.file) {
if (f.drive) {
return fetch(f.file).then(mountat(f.drive));
} else if (f.mountpoint) {
var path = f.mountpoint[0] != '/' ? '/'+ f.mountpoint : f.mountpoint;
f.file.cached = deltaFS.existsSync(path);
return fetch(f.file).then(saveat(path));
}
return null;
});
// this is kinda wrong; it really only applies when we're loading something created by Emscripten
if ('emulatorWASM' in game_data && game_data.emulatorWASM && 'WebAssembly' in window) {
promises.push(fetch({ title: "WASM Binary", url: game_data.emulatorWASM }).then(function (data) { game_data.wasmBinary = data; }));
}
Promise.all(promises).then(resolve, reject);
}
return null;
});
// this is kinda wrong; it really only applies when we're loading something created by Emscripten
if ('emulatorWASM' in game_data && game_data.emulatorWASM && 'WebAssembly' in window) {
promises.push(fetch({ title: "WASM Binary", url: game_data.emulatorWASM }).then(function (data) { game_data.wasmBinary = data; }));
}
});
});
Promise.all(promises).then(resolve, reject);
}
});
});
}
});
Expand Down Expand Up @@ -1715,60 +1720,73 @@ var Module = null;
};

var fetch_file = function (title, url, rt, optional) {
return _fetch_file(title, url, rt, optional, false);
};

var cached_file = function (title, data) {
return _fetch_file(title, data, null, false, true);
};

var _fetch_file = function (title, url, rt, optional, cached) {
var needsCSS = splash.table.dataset.hasCustomCSS == "false";
var row = addRow(splash.table);
var titleCell = row[0], statusCell = row[1];
titleCell.textContent = title;
return new Promise(function (resolve, reject) {
var xhr = new XMLHttpRequest();
xhr.open('GET', url, true);
xhr.responseType = rt || 'arraybuffer';
xhr.onprogress = function (e) {
titleCell.innerHTML = title +" <span style=\"font-size: smaller\">"+ formatSize(e) +"</span>";
};
xhr.onload = function (e) {
if (xhr.status === 200) {
success();
resolve(xhr.response);
} else if (optional) {
success();
resolve(null);
} else {
failure();
reject();
}
};
xhr.onerror = function (e) {
if (optional) {
success();
resolve(null);
} else {
failure();
reject();
}
};
function success() {
statusCell.textContent = "✔";
titleCell.parentNode.classList.add('emularity-download-success');
titleCell.textContent = title;
if (needsCSS) {
titleCell.style.fontWeight = 'bold';
titleCell.parentNode.style.backgroundColor = splash.getColor('foreground');
titleCell.parentNode.style.color = splash.getColor('background');
}
}
function failure() {
statusCell.textContent = "✘";
titleCell.parentNode.classList.add('emularity-download-failure');
titleCell.textContent = title;
if (needsCSS) {
titleCell.style.fontWeight = 'bold';
titleCell.parentNode.style.backgroundColor = splash.getColor('failure');
titleCell.parentNode.style.color = splash.getColor('background');
}
if (cached) {
success();
resolve(url); // second parameter reused as a pass–through
} else {
var xhr = new XMLHttpRequest();
xhr.open('GET', url, true);
xhr.responseType = rt || 'arraybuffer';
xhr.onprogress = function (e) {
titleCell.innerHTML = title +" <span style=\"font-size: smaller\">"+ formatSize(e) +"</span>";
};
xhr.onload = function (e) {
if (xhr.status === 200) {
success();
resolve(xhr.response);
} else if (optional) {
success();
resolve(null);
} else {
failure();
reject();
}
};
xhr.onerror = function (e) {
if (optional) {
success();
resolve(null);
} else {
failure();
reject();
}
};
xhr.send();
}
xhr.send();
});
function success() {
statusCell.textContent = "✔";
titleCell.parentNode.classList.add('emularity-download-success');
titleCell.textContent = title;
if (needsCSS) {
titleCell.style.fontWeight = 'bold';
titleCell.parentNode.style.backgroundColor = splash.getColor('foreground');
titleCell.parentNode.style.color = splash.getColor('background');
}
}
function failure() {
statusCell.textContent = "✘";
titleCell.parentNode.classList.add('emularity-download-failure');
titleCell.textContent = title;
if (needsCSS) {
titleCell.style.fontWeight = 'bold';
titleCell.parentNode.style.backgroundColor = splash.getColor('failure');
titleCell.parentNode.style.color = splash.getColor('background');
}
}
};

function keyevent(resolve) {
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