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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
/**
* For certain requests, mail servers return a multi-line response that are
* handled by this class. The definitions of multi-line responses can be found
* for NNTP at
* and for POP3 at
*
*
* This class deals with multi-line responses by:
* - Receiving each response segment and appending them all together.
* - Detecting the end of the response by seeing "\r\n.\r\n" in the last segment
* - Breaking up a response into lines
* - Removing a possible stuffed dot (.. at the beginning of a line)
* - Passing each line to a processing function, lineCallback.
* - Calling a finalization function, doneCallback, when all lines are processed
*/
export class LineReader {
// Goes true only when more than one call to read() occurs to handle the
// complete multi-line response. Used by NNTP and POP3 response parsers.
receivingMultiLineResponse = false;
// Accumulates the response data over one or more calls to read().
_data = "";
/**
* This can get called multiple times to handle a complete multi-line server
* response, appending data to _data on each call. When the full response
* is stored in _data (over one or more calls), each "line" of _data
* is then passed to lineCallback() in a loop. Once all lines are processed,
* doneCallback() is called.
*
* @param {string} data - A full or partial multi-line response received
* from the server.
* @param {Function} lineCallback - data will be separated into lines and each
* line will be processed by this callback.
* @param {Function} doneCallback - A function to be called when all the lines
* for the complete response have been processed in lineCallback.
*/
async read(data, lineCallback, doneCallback) {
this._data += data;
if (this._data == ".\r\n" || this._data.endsWith("\r\n.\r\n")) {
// Have received the complete multi-line response.
this.receivingMultiLineResponse = false;
this._data = this._data.slice(0, -3);
} else {
// Received a response but more to come.
this.receivingMultiLineResponse = true;
return;
}
let i = 0;
while (this._data) {
const index = this._data.indexOf("\r\n");
// Note: index should never be -1 since "\r\n" already found above.
let line = this._data.slice(0, index + 2);
if (line.startsWith("..")) {
// Remove stuffed dot.
line = line.slice(1);
}
lineCallback(line);
this._data = this._data.slice(index + 2);
if (++i % 1000 == 0) {
// Prevent blocking main process for too long.
await new Promise(resolve => setTimeout(resolve));
}
}
// Note: _data will be empty and receivingMultiLineResponse will be false
// at this point.
doneCallback();
}
}