gecko/toolkit/components/thumbnails/PageThumbsWorker.js

168 lines
4.4 KiB
JavaScript

/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this file,
* You can obtain one at http://mozilla.org/MPL/2.0/. */
/**
* A worker dedicated for the I/O component of PageThumbs storage.
*
* Do not rely on the API of this worker. In a future version, it might be
* fully replaced by a OS.File global I/O worker.
*/
"use strict";
importScripts("resource://gre/modules/osfile.jsm");
let File = OS.File;
let Type = OS.Shared.Type;
/**
* Communications with the controller.
*
* Accepts messages:
* {fun:function_name, args:array_of_arguments_or_null}
*
* Sends messages:
* {ok: result} / {fail: serialized_form_of_OS.File.Error}
*/
self.onmessage = function onmessage(msg) {
let data = msg.data;
let id = data.id;
let result;
if (!(data.fun in Agent)) {
throw new Error("Cannot find method " + data.fun);
}
try {
result = Agent[data.fun].apply(Agent, data.args);
} catch (ex if ex instanceof StopIteration) {
// StopIteration cannot be serialized automatically
self.postMessage({StopIteration: true, id: id});
return;
} catch (ex if ex instanceof OS.File.Error) {
// Instances of OS.File.Error know how to serialize themselves
// (deserialization ensures that we end up with OS-specific
// instances of |OS.File.Error|)
self.postMessage({fail: OS.File.Error.toMsg(ex), id:id});
return;
}
// Other exceptions do not, and should be propagated through DOM's
// built-in mechanism for uncaught errors, although this mechanism
// may lose interesting information.
self.postMessage({ok: result, id:id});
};
let Agent = {
remove: function Agent_removeFile(path) {
try {
OS.File.remove(path);
return true;
} catch (e) {
return false;
}
},
expireFilesInDirectory:
function Agent_expireFilesInDirectory(path, filesToKeep, minChunkSize) {
let entries = this.getFileEntriesInDirectory(path, filesToKeep);
let limit = Math.max(minChunkSize, Math.round(entries.length / 2));
for (let entry of entries) {
this.remove(entry.path);
// Check if we reached the limit of files to remove.
if (--limit <= 0) {
break;
}
}
return true;
},
getFileEntriesInDirectory:
function Agent_getFileEntriesInDirectory(path, skipFiles) {
let iter = new OS.File.DirectoryIterator(path);
if (!iter.exists()) {
return [];
}
let skip = new Set(skipFiles);
return [entry
for (entry in iter)
if (!entry.isDir && !entry.isSymLink && !skip.has(entry.name))];
},
moveOrDeleteAllThumbnails:
function Agent_moveOrDeleteAllThumbnails(pathFrom, pathTo) {
OS.File.makeDir(pathTo, {ignoreExisting: true});
if (pathFrom == pathTo) {
return true;
}
let iter = new OS.File.DirectoryIterator(pathFrom);
if (iter.exists()) {
for (let entry in iter) {
if (entry.isDir || entry.isSymLink) {
continue;
}
let from = OS.Path.join(pathFrom, entry.name);
let to = OS.Path.join(pathTo, entry.name);
try {
OS.File.move(from, to, {noOverwrite: true, noCopy: true});
} catch (e) {
OS.File.remove(from);
}
}
}
iter.close();
try {
OS.File.removeEmptyDir(pathFrom);
} catch (e) {
// This could fail if there's something in
// the folder we're not permitted to remove.
}
return true;
},
writeAtomic: function Agent_writeAtomic(path, buffer, options) {
return File.writeAtomic(path,
buffer,
options);
},
makeDir: function Agent_makeDir(path, options) {
return File.makeDir(path, options);
},
copy: function Agent_copy(source, dest) {
return File.copy(source, dest);
},
wipe: function Agent_wipe(path) {
let iterator = new File.DirectoryIterator(path);
try {
for (let entry in iterator) {
try {
File.remove(entry.path);
} catch (ex) {
// If a file cannot be removed, we should still continue.
// This can happen at least for any of the following reasons:
// - access denied;
// - file has been removed recently during a previous wipe
// and the file system has not flushed that yet (yes, this
// can happen under Windows);
// - file has been removed by the user or another process.
}
}
} finally {
iterator.close();
}
}
};