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diff --git a/tools/addon-sdk-1.4/packages/api-utils/docs/api-utils.md b/tools/addon-sdk-1.4/packages/api-utils/docs/api-utils.md new file mode 100644 index 0000000..d87acdb --- /dev/null +++ b/tools/addon-sdk-1.4/packages/api-utils/docs/api-utils.md @@ -0,0 +1,153 @@ +<!-- contributed by Drew Willcoxon [adw@mozilla.com] --> +<!-- edited by Noelle Murata [fiveinchpixie@gmail.com] --> + +The `api-utils` module provides some helpers useful to the SDK's high-level API +implementations. + +Introduction +------------ + +The SDK high-level API design guidelines make a number of recommendations. +This module implements some of those patterns so that your own implementations +don't need to reinvent them. + +For example, public constructors should be callable both with and without the +`new` keyword. Your module can implement this recommendation using the +`publicConstructor` function. + +Options objects or "dictionaries" are also common throughout the high-level +APIs. The guidelines recommend that public constructors should generally define +a single `options` parameter rather than defining many parameters. Since one of +the SDK's principles is to be friendly to developers, ideally all properties on +options dictionaries should be checked for correct type, and informative error +messages should be generated when clients make mistakes. With the +`validateOptions` function, your module can easily do so. + +And objects are sometimes iterable over a custom set of key/value pairs. +Such objects should have custom iterators that let consumers iterate keys, +values, or [key, value] pairs. The `addIterator` function makes it easy to do +so in a way that is consistent with the behavior of default iterators during +`for...in`, `for each...in`, and `for...in Iterator()` loops. + +<api name="publicConstructor"> +@function +Returns a function *C* that creates an instance of `privateConstructor`. *C* +may be called with or without the `new` keyword. + +The prototype of each instance returned from *C* is *C*.`prototype`, and +*C*.`prototype` is an object whose prototype is +`privateConstructor.prototype`. Instances returned from *C* are therefore +instances of both *C* and `privateConstructor`. + +Additionally, the constructor of each instance returned from *C* is *C*. + +Instances returned from *C* are automatically memory tracked using +`memory.track` under the bin name `privateConstructor.name`. + +**Example** + + function MyObject() {} + exports.MyObject = apiUtils.publicConstructor(MyObject); + +@returns {function} +A function that makes new instances of `privateConstructor`. + +@param privateConstructor {constructor} +</api> + +<api name="validateOptions"> +@function +A function to validate an options dictionary according to the specified +constraints. + +`map`, `is`, and `ok` are used in that order. + +The return value is an object whose keys are those keys in `requirements` that +are also in `options` and whose values are the corresponding return values of +`map` or the corresponding values in `options`. Note that any keys not shared +by both `requirements` and `options` are not in the returned object. + +**Examples** + +A typical use: + + var opts = { foo: 1337 }; + var requirements = { + foo: { + map: function (val) val.toString(), + is: ["string"], + ok: function (val) val.length > 0, + msg: "foo must be a non-empty string." + } + }; + var validatedOpts = apiUtils.validateOptions(opts, requirements); + // validatedOpts == { foo: "1337" } + +If the key `foo` is optional and doesn't need to be mapped: + + var opts = { foo: 1337 }; + var validatedOpts = apiUtils.validateOptions(opts, { foo: {} }); + // validatedOpts == { foo: 1337 } + + opts = {}; + validatedOpts = apiUtils.validateOptions(opts, { foo: {} }); + // validatedOpts == {} + +@returns {object} +A validated options dictionary given some requirements. If any of the +requirements are not met, an exception is thrown. + +@param options {object} +The options dictionary to validate. It's not modified. If it's null or +otherwise falsey, an empty object is assumed. + +@param requirements {object} +An object whose keys are the expected keys in `options`. Any key in +`options` that is not present in `requirements` is ignored. Each +value in `requirements` is itself an object describing the requirements +of its key. The keys of that object are the following, and each is optional: + +@prop [map] {function} +A function that's passed the value of the key in the `options`. `map`'s +return value is taken as the key's value in the final validated options, +`is`, and `ok`. If `map` throws an exception it is caught and discarded, +and the key's value is its value in `options`. + +@prop [is] {array} +An array containing the number of `typeof` type names. If the key's value is +none of these types it fails validation. Arrays and nulls are identified by +the special type names "array" and "null"; "object" will not match either. +No type coercion is done. + +@prop [ok] {function} +A function that is passed the key's value. If it returns false, the value +fails validation. + +@prop [msg] {string} +If the key's value fails validation, an exception is thrown. This string +will be used as its message. If undefined, a generic message is used, unless +`is` is defined, in which case the message will state that the value needs to +be one of the given types. +</api> + +<api name="addIterator"> +@function +Adds an iterator to the specified object that iterates keys, values, +or [key, value] pairs depending on how it is invoked, i.e.: + + for (var key in obj) { ... } // iterate keys + for each (var val in obj) { ... } // iterate values + for (var [key, val] in Iterator(obj)) { ... } // iterate pairs + +If your object only iterates either keys or values, you don't need this +function. Simply assign a generator function that iterates the keys/values +to your object's `__iterator__` property instead, f.e.: + + obj.__iterator__ = function () { for each (var i in items) yield i; } + +@param obj {object} +the object to which to add the iterator + +@param keysValsGen {function} +a generator function that yields [key, value] pairs +</api> |