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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
/**
* Serializer for lists of data that can be printed line-by-line.
* If you pass an autoLimit, it will automatically call limit() once the number
* of appended items exceeds the limit (so the number of items will never
* exceed limit*2).
*/
function TextLogger(path, autoLimit) {
// Check if we can open the path. This will throw if it doesn't work
var f = new LocalFile(path, ">>");
f.close();
this.path = path;
this.appended = 0;
if (typeof autoLimit == "number") {
this.autoLimit = autoLimit;
} else {
this.autoLimit = -1;
}
// Limit the amount of data in the file when constructing, when asked to.
if (this.autoLimit != -1) {
this.limit();
}
}
/**
* Append data (an array or single item) to the file
*/
TextLogger.prototype.append = function (data) {
if (!isinstance(data, Array)) {
data = [data];
}
// If we go over the limit, don't write everything twice:
if (this.autoLimit != -1 && data.length + this.appended > this.autoLimit) {
// Collect complete set of data instead:
var dataInFile = this.read();
var newData = dataInFile.concat(data);
// Get the last |autoLimit| items: yay JS negative indexing!
newData = newData.slice(-this.autoLimit);
this.limit(newData);
return true;
}
var file = new LocalFile(this.path, ">>");
for (var i = 0; i < data.length; i++) {
file.write(ecmaEscape(data[i]) + "\n");
}
file.close();
this.appended += data.length;
return true;
};
/**
* Limit the data already in the file to the data provided, or the count given.
*/
TextLogger.prototype.limit = function (dataOrCount) {
// Find data and count:
var data = null,
count = -1;
if (isinstance(dataOrCount, Array)) {
data = dataOrCount;
count = data.length;
} else if (typeof dataOrCount == "number") {
count = dataOrCount;
data = this.read();
} else if (this.autoLimit != -1) {
count = this.autoLimit;
data = this.read();
} else {
throw Components.Exception(
"Can't limit the length of the file without a limit...",
Cr.NS_ERROR_FAILURE
);
}
// Write the right data out. Note that we use the back of the array, not
// the front (start from data.length - count), without dropping below 0:
var start = Math.max(data.length - count, 0);
var file = new LocalFile(this.path, ">");
for (var i = start; i < data.length; i++) {
file.write(ecmaEscape(data[i]) + "\n");
}
file.close();
this.appended = 0;
return true;
};
/**
* Reads out the data currently in the file, and returns an array.
*/
TextLogger.prototype.read = function () {
var rv = [],
parsedLines = [],
buffer = "";
var file = new LocalFile(this.path, "<");
while (true) {
var newData = file.read();
if (newData) {
buffer += newData;
} else if (buffer.length == 0) {
break;
}
// Got more data in the buffer, so split into lines. Unless we're
// done, the last one might not be complete yet, so save that one.
// We split rather strictly on line ends, because empty lines should
// be preserved.
var lines = buffer.split(/\r?\n/);
if (!newData) {
buffer = "";
} else {
buffer = lines.pop();
}
rv = rv.concat(lines);
}
// Unescape here...
for (var i = 0; i < rv.length; i++) {
rv[i] = ecmaUnescape(rv[i]);
}
return rv;
};