You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
 
 
 
 
 
 

156 lines
3.9 KiB

var posix = require("./posix");
var events = require('events');
/*jslint onevar: true, undef: true, eqeqeq: true, plusplus: true, regexp: true, newcap: true, immed: true */
/*globals exports, node, __filename */
exports.debugLevel = 0; // Increase to get more verbose debug output
function debugMessage (msg) {
if (exports.debugLevel > 0) {
process.error(__filename + ": " + msg.toString());
}
}
function debugObject (obj) {
if (exports.debugLevel > 0) {
process.error(__filename + ": " + JSON.stringify(obj));
}
}
exports.read = posix.cat;
exports.write = function (filename, data, encoding) {
var promise = new events.Promise();
encoding = encoding || "utf8"; // default to utf8
posix.open(filename, process.O_WRONLY | process.O_TRUNC | process.O_CREAT, 0666)
.addCallback(function (fd) {
function doWrite (_data) {
posix.write(fd, _data, 0, encoding)
.addErrback(function () {
posix.close(fd);
promise.emitError();
})
.addCallback(function (written) {
if (written === _data.length) {
posix.close(fd);
promise.emitSuccess();
} else {
doWrite(_data.slice(written));
}
});
}
doWrite(data);
})
.addErrback(function () {
promise.emitError();
});
return promise;
};
exports.File = function (filename, mode, options) {
var self = this;
options = options || {};
self.encoding = options.encoding || "utf8";
self.filename = filename;
self.actionQueue = [];
self.currentAction = null;
switch (mode) {
case "r":
self.flags = process.O_RDONLY;
break;
case "r+":
self.flags = process.O_RDWR;
break;
case "w":
self.flags = process.O_CREAT | process.O_TRUNC | process.O_WRONLY;
break;
case "w+":
self.flags = process.O_CREAT | process.O_TRUNC | process.O_RDWR;
break;
case "a":
self.flags = process.O_APPEND | process.O_CREAT | process.O_WRONLY;
break;
case "a+":
self.flags = process.O_APPEND | process.O_CREAT | process.O_RDWR;
break;
default:
throw new Error("Unknown mode");
}
self.open(self.filename, self.flags, 0666).addCallback(function (fd) {
debugMessage(self.filename + " opened. fd = " + fd);
self.fd = fd;
}).addErrback(function () {
self.emit("error", ["open"]);
});
};
var proto = exports.File.prototype;
proto._maybeDispatch = function () {
var self, args, method, promise, userPromise;
self = this;
if (self.currentAction) { return; }
self.currentAction = self.actionQueue.shift();
if (!self.currentAction) { return; }
debugObject(self.currentAction);
args = self.currentAction.args || [];
method = self.currentAction.method;
if (method !== "open") {
args.unshift(self.fd);
}
if (!args[3] && (method === "read" || method === "write")) {
args[3] = self.encoding;
}
promise = posix[method].apply(self, args);
userPromise = self.currentAction.promise;
promise.addCallback(function () {
process.assert(self.currentAction.promise === userPromise);
userPromise.emitSuccess.apply(userPromise, arguments);
self.currentAction = null;
self._maybeDispatch();
}).addErrback(function () {
debugMessage("Error in method " + method);
process.assert(self.currentAction.promise === userPromise);
userPromise.emitError.apply(userPromise, arguments);
self.currentAction = null;
self._maybeDispatch();
});
};
proto._queueAction = function (method, args) {
var userPromise = new events.Promise();
this.actionQueue.push({ method: method, args: args, promise: userPromise });
this._maybeDispatch();
return userPromise;
};
(["open", "write", "read", "close"]).forEach(function (name) {
proto[name] = function () {
return this._queueAction(name, Array.prototype.slice.call(arguments, 0));
};
});