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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/. */
this.EXPORTED_SYMBOLS = ["IOUtils"];
Components.utils.import("resource://gre/modules/Services.jsm");
var Cc = Components.classes;
var Ci = Components.interfaces;
var kStringBlockSize = 4096;
var kStreamBlockSize = 8192;
var IOUtils =
{
/**
* Read a file containing ASCII text into a string.
*
* @param aFile An nsIFile representing the file to read or a string containing
* the file name of a file under user's profile.
* @returns A string containing the contents of the file, presumed to be ASCII
* text. If the file didn't exist, returns null.
*/
loadFileToString: function(aFile) {
let file;
if (!(aFile instanceof Ci.nsIFile)) {
file = Services.dirsvc.get("ProfD", Ci.nsIFile);
file.append(aFile);
} else {
file = aFile;
}
if (!file.exists())
return null;
let fstream = Cc["@mozilla.org/network/file-input-stream;1"]
.createInstance(Ci.nsIFileInputStream);
// PR_RDONLY
fstream.init(file, 0x01, 0, 0);
let sstream = Cc["@mozilla.org/scriptableinputstream;1"]
.createInstance(Ci.nsIScriptableInputStream);
sstream.init(fstream);
let data = "";
while (sstream.available()) {
data += sstream.read(kStringBlockSize);
}
sstream.close();
fstream.close();
return data;
},
/**
* Save a string containing ASCII text into a file. The file will be overwritten
* and contain only the given text.
*
* @param aFile An nsIFile representing the file to write or a string containing
* the file name of a file under user's profile.
* @param aData The string to write.
* @param aPerms The octal file permissions for the created file. If unset
* the default of 0o600 is used.
*/
saveStringToFile: function(aFile, aData, aPerms = 0o600) {
let file;
if (!(aFile instanceof Ci.nsIFile)) {
file = Services.dirsvc.get("ProfD", Ci.nsIFile);
file.append(aFile);
} else {
file = aFile;
}
let foStream = Cc["@mozilla.org/network/safe-file-output-stream;1"]
.createInstance(Ci.nsIFileOutputStream);
// PR_WRONLY + PR_CREATE_FILE + PR_TRUNCATE
foStream.init(file, 0x02 | 0x08 | 0x20, aPerms, 0);
// safe-file-output-stream appears to throw an error if it doesn't write everything at once
// so we won't worry about looping to deal with partial writes.
// In case we try to use this function for big files where buffering
// is needed we could use the implementation in saveStreamToFile().
foStream.write(aData, aData.length);
foStream.QueryInterface(Ci.nsISafeOutputStream).finish();
foStream.close();
},
/**
* Saves the given input stream to a file.
*
* @param aIStream The input stream to save.
* @param aFile The file to which the stream is saved.
* @param aPerms The octal file permissions for the created file. If unset
* the default of 0o600 is used.
*/
saveStreamToFile: function(aIStream, aFile, aPerms = 0o600) {
if (!(aIStream instanceof Ci.nsIInputStream))
throw new Error("Invalid stream passed to saveStreamToFile");
if (!(aFile instanceof Ci.nsIFile))
throw new Error("Invalid file passed to saveStreamToFile");
let fstream = Cc["@mozilla.org/network/safe-file-output-stream;1"]
.createInstance(Ci.nsIFileOutputStream);
let buffer = Cc["@mozilla.org/network/buffered-output-stream;1"]
.createInstance(Ci.nsIBufferedOutputStream);
// Write the input stream to the file.
// PR_WRITE + PR_CREATE + PR_TRUNCATE
fstream.init(aFile, 0x04 | 0x08 | 0x20, aPerms, 0);
buffer.init(fstream, kStreamBlockSize);
buffer.writeFrom(aIStream, aIStream.available());
// Close the output streams.
if (buffer instanceof Components.interfaces.nsISafeOutputStream)
buffer.finish();
else
buffer.close();
if (fstream instanceof Components.interfaces.nsISafeOutputStream)
fstream.finish();
else
fstream.close();
// Close the input stream.
aIStream.close();
return aFile;
},
/**
* Returns size of system memory.
*/
getPhysicalMemorySize: function() {
return Services.sysinfo.getPropertyAsInt64("memsize");
},
};
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