392 lines
13 KiB

/*
* grunt
* http://gruntjs.com/
*
* Copyright (c) 2012 "Cowboy" Ben Alman
* Licensed under the MIT license.
* https://github.com/gruntjs/grunt/blob/master/LICENSE-MIT
*/
(function(exports) {
// Construct-o-rama.
function Task() {
// Information about the currently-running task.
this.current = {};
// Helpers.
this._helpers = {};
// Tasks.
this._tasks = {};
// Task queue.
this._queue = [];
// Queue placeholder (for dealing with nested tasks).
this._placeholder = {placeholder: true};
// Queue marker (for clearing the queue programatically).
this._marker = {marker: true};
// Options.
this._options = {};
// Is the queue running?
this._running = false;
// Success status of completed tasks.
this._success = {};
}
// Expose the constructor function.
exports.Task = Task;
// Create a new Task instance.
exports.create = function() {
return new Task();
};
// Error constructors.
function TaskError(message) {
Error.captureStackTrace(this, TaskError);
this.message = message;
}
TaskError.prototype = Object.create(Error.prototype);
TaskError.prototype.name = 'TaskError';
function HelperError(message) {
Error.captureStackTrace(this, HelperError);
this.message = message;
}
HelperError.prototype = Object.create(Error.prototype);
HelperError.prototype.name = 'HelperError';
// Expose the ability to create a new taskError.
Task.prototype.taskError = function(message, e) {
var error = new TaskError(message);
error.origError = e;
return error;
};
// Register a new helper.
Task.prototype.registerHelper = function(name, fn) {
// Add task into cache.
this._helpers[name] = fn;
// Make chainable!
return this;
};
// Rename a helper. This might be useful if you want to override the default
// behavior of a helper, while retaining the old name (to avoid having to
// completely recreate an already-made task just because you needed to
// override or extend a built-in helper).
Task.prototype.renameHelper = function(oldname, newname) {
// Rename helper.
this._helpers[newname] = this._helpers[oldname];
// Remove old name.
delete this._helpers[oldname];
// Make chainable!
return this;
};
// If the task runner is running or an error handler is not defined, throw
// an exception. Otherwise, call the error handler directly.
Task.prototype._throwIfRunning = function(obj) {
if (this._running || !this._options.error) {
// Throw an exception that the task runner will catch.
throw obj;
} else {
// Not inside the task runner. Call the error handler and abort.
this._options.error.call({name: null}, obj);
}
};
// Execute a helper.
Task.prototype.helper = function(isDirective, name) {
var args = [].slice.call(arguments, 1);
if (isDirective !== true) {
name = isDirective;
isDirective = false;
} else {
args = args.slice(1);
}
var helper = this._helpers[name];
if (!helper) {
// Helper not found.
this._throwIfRunning(new HelperError('Helper "' + name + '" not found.'));
return;
}
// Provide a few useful values on this.
var context = {args: args, flags: {}};
// Maybe you want to use flags instead of positional args?
args.forEach(function(arg) { context.flags[arg] = true; });
// Let the user know if it was used as a directive.
if (isDirective) { context.directive = true; }
// Invoke helper with any remaining arguments and return its value.
return helper.apply(context, args);
};
// If a <foo:bar:baz> directive is passed, return ["foo", "bar", "baz"],
// otherwise null.
var directiveRe = /^<(.*)>$/;
Task.prototype.getDirectiveParts = function(str) {
var matches = str.match(directiveRe);
// If the string doesn't look like a directive, return null.
if (!matches) { return null; }
// Split the name into parts.
var parts = matches[1].split(':');
// If a matching helper was found, return the parts, otherwise null.
return this._helpers[parts[0]] ? parts : null;
};
// If value matches the <handler:arg1:arg2> format, and the specified handler
// exists, it's a directive. Execute the matching handler and return its
// value. If not, but an optional callback was passed, pass the value into
// the callback and return its result. If no callback was specified, return
// the value.
Task.prototype.directive = function(value, fn) {
// Get parts if a string was passed and it looks like a directive.
var directive = typeof value === 'string' ? this.getDirectiveParts(value) : null;
if (directive) {
// If it looks like a directive and a matching helper exists, call the
// helper by applying all directive parts and return its value.
return this.helper.apply(this, [true].concat(directive));
} else if (fn) {
// Not a directive, but a callback was passed. Pass the value into the
// callback and return its result.
return fn(value);
}
// A callback wasn't specified or a valid handler wasn't found, so just
// return the value.
return value;
};
// Register a new task.
Task.prototype.registerTask = function(name, info, fn) {
// If optional "info" string is omitted, shuffle arguments a bit.
if (fn == null) {
fn = info;
info = '';
}
// String or array of strings was passed instead of fn.
var tasks;
if (typeof fn !== 'function') {
// Array of task names.
tasks = this.parseArgs([fn]);
// This task function just runs the specified tasks.
fn = this.run.bind(this, fn);
fn.alias = true;
// Generate an info string if one wasn't explicitly passed.
if (!info) {
info = 'Alias for "' + tasks.join(' ') + '" task' +
(tasks.length === 1 ? '' : 's') + '.';
}
}
// Add task into cache.
this._tasks[name] = {name: name, info: info, fn: fn};
// Make chainable!
return this;
};
// Is the specified task an alias?
Task.prototype.isTaskAlias = function(name) {
return !!this._tasks[name].fn.alias;
};
// Rename a task. This might be useful if you want to override the default
// behavior of a task, while retaining the old name. This is a billion times
// easier to implement than some kind of in-task "super" functionality.
Task.prototype.renameTask = function(oldname, newname) {
// Rename helper.
this._tasks[newname] = this._tasks[oldname];
// Update name property of task.
this._tasks[newname].name = newname;
// Remove old name.
delete this._tasks[oldname];
// Make chainable!
return this;
};
// Argument parsing helper. Supports these signatures:
// fn('foo') // ['foo']
// fn('foo bar baz') // ['foo', 'bar', 'baz']
// fn('foo', 'bar', 'baz') // ['foo', 'bar', 'baz']
// fn(['foo', 'bar', 'baz']) // ['foo', 'bar', 'baz']
Task.prototype.parseArgs = function(_arguments) {
// If there are multiple (or zero) arguments, convert the _arguments object
// into an array and return that.
return _arguments.length !== 1 ? [].slice.call(_arguments) :
// Return the first argument if it's an Array.
Array.isArray(_arguments[0]) ? _arguments[0] :
// Split the first argument on space.
typeof _arguments[0] === 'string' ? _arguments[0].split(/\s+/) :
// Just return an array containing the first argument. (todo: deprecate)
[_arguments[0]];
};
// Given a task name, determine which actual task will be called, and what
// arguments will be passed into the task callback. "foo" -> task "foo", no
// args. "foo:bar:baz" -> task "foo:bar:baz" with no args (if "foo:bar:baz"
// task exists), otherwise task "foo:bar" with arg "baz" (if "foo:bar" task
// exists), otherwise task "foo" with args "bar" and "baz".
Task.prototype._taskPlusArgs = function(name) {
// Task name / argument parts.
var parts = name.split(':');
// Start from the end, not the beginning!
var i = parts.length;
var task;
do {
// Get a task.
task = this._tasks[parts.slice(0, i).join(':')];
// If the task doesn't exist, decrement `i`, and if `i` is greater than
// 0, repeat.
} while (!task && --i > 0);
// Just the args.
var args = parts.slice(i);
// Maybe you want to use them as flags instead of as positional args?
var flags = {};
args.forEach(function(arg) { flags[arg] = true; });
// The task to run and the args to run it with.
return {task: task, nameArgs: name, args: args, flags: flags};
};
// Append things to queue in the correct spot.
Task.prototype._push = function(things) {
// Get current placeholder index.
var index = this._queue.indexOf(this._placeholder);
if (index === -1) {
// No placeholder, add task+args objects to end of queue.
this._queue = this._queue.concat(things);
} else {
// Placeholder exists, add task+args objects just before placeholder.
[].splice.apply(this._queue, [index, 0].concat(things));
}
};
// Enqueue a task.
Task.prototype.run = function() {
// Parse arguments into an array, returning an array of task+args objects.
var things = this.parseArgs(arguments).map(this._taskPlusArgs, this);
// Throw an exception if any tasks weren't found.
var fails = things.filter(function(thing) { return !thing.task; });
if (fails.length > 0) {
this._throwIfRunning(new TaskError('Task "' + fails[0].nameArgs + '" not found.'));
return this;
}
// Append things to queue in the correct spot.
this._push(things);
// Make chainable!
return this;
};
// Add a marker to the queue to facilitate clearing it programatically.
Task.prototype.mark = function() {
this._push(this._marker);
// Make chainable!
return this;
};
// Begin task queue processing. Ie. run all tasks.
Task.prototype.start = function() {
// Abort if already running.
if (this._running) { return false; }
// Actually process the next task.
var nextTask = function() {
// Async flag.
var async = false;
// Get next task+args object from queue.
var thing;
// Skip any placeholders or markers.
do {
thing = this._queue.shift();
} while (thing === this._placeholder || thing === this._marker);
// If queue was empty, we're all done.
if (!thing) {
this._running = false;
if (this._options.done) {
this._options.done();
}
return;
}
// Add a placeholder to the front of the queue.
this._queue.unshift(this._placeholder);
// Update the internal status object and run the next task.
var complete = function(status, errorObj) {
this.current = {};
// A task has "failed" only if it returns false (async) or if the
// function returned by .async is passed false.
this._success[thing.nameArgs] = status !== false;
// If task failed, call error handler.
if (status === false && this._options.error) {
this._options.error.call({name: thing.task.name, nameArgs: thing.nameArgs}, errorObj ||
new TaskError('Task "' + thing.nameArgs + '" failed.'));
}
// Run the next task.
nextTask();
}.bind(this);
// Expose some information about the currently-running task.
this.current = {
// The current task name plus args, as-passed.
nameArgs: thing.nameArgs,
// The current task name.
name: thing.task.name,
// The current task arguments.
args: thing.args,
// The current arguments, available as named flags.
flags: thing.flags,
// When called, sets the async flag and returns a function that can
// be used to continue processing the queue.
async: function() {
async = true;
return complete;
}
};
try {
// Get the current task and run it, setting `this` inside the task
// function to be something useful.
var status = thing.task.fn.apply(this.current, thing.args);
// If the async flag wasn't set, process the next task in the queue.
if (!async) {
complete(status);
}
} catch (e) {
if (e instanceof TaskError || e instanceof HelperError) {
complete(false, e);
} else {
throw e;
}
}
}.bind(this);
// Update flag.
this._running = true;
// Process the next task.
nextTask();
};
// Clear remaining tasks from the queue.
Task.prototype.clearQueue = function(options) {
if (!options) { options = {}; }
if (options.untilMarker) {
this._queue.splice(0, this._queue.indexOf(this._marker) + 1);
} else {
this._queue = [];
}
// Make chainable!
return this;
};
// Test to see if all of the given tasks have succeeded.
Task.prototype.requires = function() {
this.parseArgs(arguments).forEach(function(name) {
var success = this._success[name];
if (!success) {
throw new TaskError('Required task "' + name +
'" ' + (success === false ? 'failed' : 'missing') + '.');
}
}.bind(this));
};
// Override default options.
Task.prototype.options = function(options) {
Object.keys(options).forEach(function(name) {
this._options[name] = options[name];
}.bind(this));
};
}(typeof exports === 'object' && exports || this));