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/* 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/. */
/**
* Handles serialization of Download objects and persistence into a file, so
* that the state of downloads can be restored across sessions.
*
* The file is stored in JSON format, without indentation. With indentation
* applied, the file would look like this:
*
* {
* "list": [
* {
* "source": "http://www.example.com/download.txt",
* "target": "/home/user/Downloads/download.txt"
* },
* {
* "source": {
* "url": "http://www.example.com/download.txt",
* "referrerInfo": serialized string represents referrerInfo object
* },
* "target": "/home/user/Downloads/download-2.txt"
* }
* ]
* }
*/
// Time after which insecure downloads that have not been dealt with on shutdown
// get removed (5 minutes).
const MAX_INSECURE_DOWNLOAD_AGE_MS = 5 * 60 * 1000;
const lazy = {};
ChromeUtils.defineESModuleGetters(lazy, {
Downloads: "resource://gre/modules/Downloads.sys.mjs",
});
ChromeUtils.defineLazyGetter(lazy, "gTextDecoder", function () {
return new TextDecoder();
});
ChromeUtils.defineLazyGetter(lazy, "gTextEncoder", function () {
return new TextEncoder();
});
/**
* Handles serialization of Download objects and persistence into a file, so
* that the state of downloads can be restored across sessions.
*
* @param aList
* DownloadList object to be populated or serialized.
* @param aPath
* String containing the file path where data should be saved.
*/
export var DownloadStore = function (aList, aPath) {
this.list = aList;
this.path = aPath;
};
DownloadStore.prototype = {
/**
* DownloadList object to be populated or serialized.
*/
list: null,
/**
* String containing the file path where data should be saved.
*/
path: "",
/**
* This function is called with a Download object as its first argument, and
* should return true if the item should be saved.
*/
onsaveitem: () => true,
/**
* Loads persistent downloads from the file to the list.
*
* @return {Promise}
* @resolves When the operation finished successfully.
* @rejects JavaScript exception.
*/
load: function DS_load() {
return (async () => {
let bytes;
try {
bytes = await IOUtils.read(this.path);
} catch (ex) {
if (!(ex.name == "NotFoundError")) {
throw ex;
}
// If the file does not exist, there are no downloads to load.
return;
}
// Set this to true when we make changes to the download list that should
// be reflected in the file again.
let storeChanges = false;
let removePromises = [];
let storeData = JSON.parse(lazy.gTextDecoder.decode(bytes));
// Create live downloads based on the static snapshot.
for (let downloadData of storeData.list) {
try {
let download = await lazy.Downloads.createDownload(downloadData);
// Insecure downloads that have not been dealt with on shutdown should
// get cleaned up and removed from the download list on restart unless
// they are very new
if (
download.error?.becauseBlockedByReputationCheck &&
download.error.reputationCheckVerdict == "Insecure" &&
Date.now() - download.startTime > MAX_INSECURE_DOWNLOAD_AGE_MS
) {
removePromises.push(download.removePartialData());
storeChanges = true;
continue;
}
try {
if (!download.succeeded && !download.canceled && !download.error) {
// Try to restart the download if it was in progress during the
// previous session. Ignore errors.
download.start().catch(() => {});
} else {
// If the download was not in progress, try to update the current
// progress from disk. This is relevant in case we retained
// partially downloaded data.
await download.refresh();
}
} finally {
// Add the download to the list if we succeeded in creating it,
// after we have updated its initial state.
await this.list.add(download);
}
} catch (ex) {
// If an item is unrecognized, don't prevent others from being loaded.
console.error(ex);
}
}
if (storeChanges) {
try {
await Promise.all(removePromises);
await this.save();
} catch (ex) {
console.error(ex);
}
}
})();
},
/**
* Saves persistent downloads from the list to the file.
*
* If an error occurs, the previous file is not deleted.
*
* @return {Promise}
* @resolves When the operation finished successfully.
* @rejects JavaScript exception.
*/
save: function DS_save() {
return (async () => {
let downloads = await this.list.getAll();
// Take a static snapshot of the current state of all the downloads.
let storeData = { list: [] };
let atLeastOneDownload = false;
for (let download of downloads) {
try {
if (!this.onsaveitem(download)) {
continue;
}
let serializable = download.toSerializable();
if (!serializable) {
// This item cannot be persisted across sessions.
continue;
}
storeData.list.push(serializable);
atLeastOneDownload = true;
} catch (ex) {
// If an item cannot be converted to a serializable form, don't
// prevent others from being saved.
console.error(ex);
}
}
if (atLeastOneDownload) {
// Create or overwrite the file if there are downloads to save.
let bytes = lazy.gTextEncoder.encode(JSON.stringify(storeData));
await IOUtils.write(this.path, bytes, {
tmpPath: this.path + ".tmp",
});
} else {
// Remove the file if there are no downloads to save at all.
try {
await IOUtils.remove(this.path);
} catch (ex) {
if (!(ex.name == "NotFoundError" || ex.name == "NotAllowedError")) {
throw ex;
}
// On Windows, we may get an access denied error instead of a no such
// file error if the file existed before, and was recently deleted.
}
}
})();
},
};
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