From a065e04d529da1d847b5062a12c46d916408bf32 Mon Sep 17 00:00:00 2001 From: Peter Bengtsson Date: Tue, 8 Dec 2020 21:46:22 -0500 Subject: update based on https://github.com/mdn/yari/issues/2028 --- files/ja/xpcomutils.jsm/index.html | 491 ------------------------------------- 1 file changed, 491 deletions(-) delete mode 100644 files/ja/xpcomutils.jsm/index.html (limited to 'files/ja/xpcomutils.jsm') diff --git a/files/ja/xpcomutils.jsm/index.html b/files/ja/xpcomutils.jsm/index.html deleted file mode 100644 index d392290bb9..0000000000 --- a/files/ja/xpcomutils.jsm/index.html +++ /dev/null @@ -1,491 +0,0 @@ ---- -title: XPCOMUtils.jsm -slug: XPCOMUtils.jsm -tags: - - NeedsContent - - 'XPCOM:Language Bindings' - - XPConnect -translation_of: Mozilla/JavaScript_code_modules/XPCOMUtils.jsm ---- -

XPCOMUtils.jsm は JS コンポーネントローダによって読み込まれる JavaScript コンポーネントのためのユーティリティを含んだモジュールです。

- -

-

To use this, you first need to import the code module into your JavaScript scope:

-

- -
Components.utils.import("resource://gre/modules/XPCOMUtils.jsm");
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Using XPCOMUtils

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Exposing a JavaScript class as a component using these utility methods requires four key steps:

- -
    -
  1. Import XPCOMUtils.jsm, as explained previously.
    2. -
  2. Declare the class (or multiple classes) implementing the component(s).
    3. -
  3. Create an array of component constructors.
    4. -
  4. Define the NSGetFactory() or NSGetModule() entry point.
    5. -
- -

Pseudocode

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This section provides some pseudocode that demonstrates how to put together a JavaScript class based on the steps listed above.

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Constructor

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The constructor is a simple method that handles any required initialization tasks.

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function MyComponent() {
-  // initialize the component here
-}
- -

Class declaration

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Declare the class prototype, using a form similar to this.

- -
MyComponent.prototype = {
-  // properties required for XPCOM registration:
-  classDescription: "unique text description",
-  classID:          Components.ID("{xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx}"),
-  contractID:       "@example.com/xxx;1",
-
-  // [optional] custom factory (an object implementing nsIFactory). If not
-  // provided, the default factory is used, which returns
-  // |(new MyComponent()).QueryInterface(iid)| in its createInstance().
-  _xpcom_factory: { ... },
-
-  // [optional] an array of categories to register this component in.
-  _xpcom_categories: [{
-    // Each object in the array specifies the parameters to pass to
-    // nsICategoryManager.addCategoryEntry(). 'true' is passed for
-    // both aPersist and aReplace params.
-    category: "some-category",
-    // optional, defaults to the object's classDescription
-    entry: "entry name",
-    // optional, defaults to the object's contractID (unless
-    // 'service' is specified)
-    value: "...",
-    // optional, defaults to false. When set to true, and only if 'value'
-    // is not specified, the concatenation of the string "service," and the
-    // object's contractID is passed as aValue parameter of addCategoryEntry.
-    service: true,
-    // optional array of applications' IDs in the form:
-    // [ "{xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx}", ... ]
-    // If this is defined, the component is registered in this
-    // category only on the specified applications.
-    apps: [ ... ]
-  }],
-
-  // QueryInterface implementation, e.g. using the generateQI helper
-  QueryInterface: XPCOMUtils.generateQI(
-    [Components.interfaces.nsIObserver,
-     Components.interfaces.nsIMyInterface,
-     "nsIFoo",
-     "nsIBar" ]),
-
-  // [optional] classInfo implementation, e.g. using the generateCI helper.
-  // Will be automatically returned from QueryInterface if that was
-  // generated with the generateQI helper.
-  classInfo: XPCOMUtils.generateCI(
-    {classID: Components.ID("{xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx}"),
-     contractID: "@example.com/xxx;1",
-     classDescription: "unique text description",
-     interfaces: [Components.interfaces.nsIObserver,
-                  Components.interfaces.nsIMyInterface,
-                  "nsIFoo",
-                  "nsIBar"],
-     flags: Ci.nsIClassInfo.SINGLETON}),
-
-  // ...component implementation...
-};
- -
-

Note: The ability to register the component in a category only on specific applications by adding the apps field to a category entry was added in Gecko 2.

-
- -

Notice that the QueryInterface() method implemented by the component simply calls the generateQI() method provided by the XPCOMUtils code module.

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Create an array of component constructors

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You need to create an array that lists the constructors for each component. This array can of course have just one entry:

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var components = [MyComponent];
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Here, we're calling the array components.

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Create the NSGetFactory() or NSGetModule() entry point

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Finally, you need to implement the NSGetModule() entry point so Gecko can start up your component:

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// "components" is the array created in the previous section
-if ("generateNSGetFactory" in XPCOMUtils)
-  var NSGetFactory = XPCOMUtils.generateNSGetFactory(components);  // Gecko 2.0+
-else
-  var NSGetModule = XPCOMUtils.generateNSGetModule(components);    // Gecko 1.9.x
- -

Method overview

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
function defineLazyGetter(aObject, aName, aLambda);
function defineLazyModuleGetter(aObject, aName, aResource, [optional] aSymbol);
function defineLazyServiceGetter(aObject, aName, aContract, aInterfaceName);
function generateNSGetFactory(componentsArray);
function generateCI(classInfo);
function generateQI(interfaces);
void importRelative(that, path, scope);
generator IterSimpleEnumerator(enumerator, interface);
generator IterStringEnumerator(enumerator);
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Attributes

- - - - - - - - - - - - - - -
AttributeTypeDescription
categoryManager{{ interface("nsICategoryManager") }}Returns a reference to {{ interface("nsICategoryManager") }}.
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Methods

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defineLazyGetter()

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Getter functions in JavaScript give you a way to define a property of an object, but not calculate the property's value until it is accessed. A getter defers the cost of calculating the value until the value is needed, and if it is never needed, you never pay the cost.

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A "lazy getter" provides an additional optimization: the value is calculated the first time the getter is called, and is then cached (or memoized), so subsequent accesses return the cached value without recalculating it.

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This means that you shouldn't use a lazy getter for a property whose value you expect to change, because the getter will not recalculate the value.

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defineLazyGetter takes three arguments:

- - - -

Example for this is seen at bottom of this page here.

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function defineLazyGetter(
-  aObject,
-  aName,
-  aLambda
-);
- -
Parameters
- -
-
aObject
-
The object into which to add the new lazy getter function.
-
aName
-
The name of the getter function to create.
-
aLambda
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A function that returns the value the getter should return. This function is called exactly once.  this will reference aObject during execution of the function.
-
- -

defineLazyModuleGetter()

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Defines a getter on a specified object for a module. The module will not be imported until first use.

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function defineLazyModuleGetter(
-  aObject,
-  aName,
-  aResource,
-  aSymbol
-);
- -
Parameters
- -
-
aObject
-
The object to define the lazy getter on.
-
aName
-
The name of the getter to define on aObject for the module.
-
aResource
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The URL used to obtain the module.
-
aSymbol
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The name of the symbol exported by the module. This parameter is optional and defaults to aName.
-
- -

defineLazyServiceGetter()

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Defines a function on a specified object which acts as a getter for a service. The service isn't obtained until the first time it's used.

- -
function defineLazyServiceGetter(
-  aObject,
-  aName,
-  aContract,
-  aInterfaceName
-);
- -
Parameters
- -
-
aObject
-
The object into which to add the new lazy service getter function.
-
aName
-
The name of the getter function to create.
-
aContract
-
The contract to use to obtain the service.
-
aInterfaceName
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The name of the interface to query the service to.
-
- -

 

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generateNSGetFactory()

- -

 

- -

Generates the NSGetFactory() function along with the factory definition.

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Function generateNSGetFactory(
-  componentsArray
-);
- -
Parameters
- -
-
componentsArray
-
An array of component constructors.
-
- -
Return value
- -

A function that will return the factory for the components and can be assigned to NSGetFactory global variable.

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generateCI()

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Generates an {{ interface("nsIClassInfo") }} implementation for a component. The returned object should be assigned to the classInfo property of a JS object, the QueryInterface() function generated by generateQI will return it automatically then.

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function generateCI(
-  classInfo
-);
- -
Parameters
- -
-
classInfo
-
An object containing the optional properties interfaces, contractID, classDescription, classID, flags. This parameter should not be the component itself because that would cause a memory leak.
-
- -
Return value
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An {{ interface("nsIClassInfo") }} implementation returning the values of the properties from the classInfo parameter in its various properties.

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Exceptions thrown
- -

This method throws an exception with the message "In generateCI, don't use a component for generating classInfo" if classInfo parameter is an XPCOM component.

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generateQI()

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Generates a QueryInterface() function implementation. You need to assign the returned function to the QueryInterface property of a JavaScript object.

- -

When the generated method is invoked on that object, it checks to see if the specified IID is listed in the array specified by the interfaces parameter; if it is, this (that is, the object itself) is returned. Otherwise, null is returned.

- -
function generateQI(
-  interfaces
-);
- -
Parameters
- -
-
interfaces
-
An array of interfaces implemented by the component.
-
- -
Return value
- -

A QueryInterface() function implementation.

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Remarks
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When you implement an interface that inherits from another one, you should generally list all the base interfaces explicitly, except for {{ Interface("nsISupports") }}. For example, if your component implements {{ Interface("nsIStreamConverter") }}:

- -
MyComponent.prototype = {
-  QueryInterface: XPCOMUtils.generateQI([
-    Components.interfaces.nsIRequestObserver,
-    Components.interfaces.nsIStreamListener,
-    Components.interfaces.nsIStreamConverter,
-  ]),
-
-  // ...methods...
-}
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importRelative()

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Imports a JavaScript code module given the calling JavaScript code module's global object (you should specify this) and a path relative to that module. This lets modules bundled in a package load one another without having to hard-code full paths.

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void importRelative(
-  that,
-  path,
-  scope
-);
- -
Parameters
- -
-
that
-
The JavaScript Object of the calling JavaScript code module's global scope. You should simply pass this.
-
path
-
The relative path of the JavaScript code module to import.
-
scope
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An optional object to import into; if omitted, the object passed in for the that parameter is used.
-
- -
Remarks
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This lets an extension bundle its own JavaScript code modules within itself and have them load one another. For example, if an extension named "MyExtension" bundles foo.jsm and bar.jsm, and foo.jsm needs to load bar.jsm, it can do so like this:

- -
Components.utils.import("resource://gre/modules/XPCOMUtils.jsm");
-XPCOMUtils.importRelative(this, "bar.jsm");
- -

In other words: importRelative will only work from other code modules (such as JSM files). It will NOT work from overlay scripts or bootstrap.js or etc. Details can be found here: {{bug("628669")}}

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IterSimpleEnumerator()

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Wraps an {{ Interface("nsISimpleEnumerator") }} instance into a JavaScript generator that can be easily iterated over.

- -
generator IterSimpleEnumerator(
-  enumerator,
-  interface
-);
- -
Parameters
- -
-
enumerator
-
The {{ Interface("nsISimpleEnumerator") }} instance to iterate over.
-
interface
-
The expected interface for each element.
-
- -
Return value
- -

A generator yielding enumerated objects.

- -
Example
- -
const nsIFile = Components.interfaces.nsIFile;
-for (var file in XPCOMUtils.IterSimpleEnumerator(dir.directoryEntries, nsIFile))
-  console.log(file.path);
- -

IterStringEnumerator()

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Wraps an {{ Interface("nsIStringEnumerator") }} or {{ Interface("nsIUTF8StringEnumerator") }} instance into a JavaScript generator that can be easily iterated over.

- -
generator IterStringEnumerator(
-  enumerator
-);
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Parameters
- -
-
enumerator
-
The {{ Interface("nsIStringEnumerator") }} or {{ Interface("nsIUTF8StringEnumerator") }} instance to iterate over.
-
- -
Return value
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A generator yielding enumerated strings.

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Example
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for (var section in XPCOMUtils.IterStringEnumerator(iniParser.getSections()))
-  console.log(section);
- -

Post-registration callback

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The post-registration callback called by generateModule() should have the following signature:

- -
postRegister(
-  nsIComponentManager compMgr,
-  nsIFile fileSpec,
-  componentsArray
-);
- -
Parameters
- -
-
compMgr
-
An {{ interface("nsIComponentManager") }} instance to use for managing the component.
-
fileSpec
-
An {{ interface("nsIFile") }} instance for... what?
-
componentsArray
-
An array of the components, as passed to generateModule().
-
- -

The function doesn't need to return a value.

- -

Pre-unregistration callback

- -

The pre-unregistration callback passed to generateModule() should have the following signature:

- -
preUnregister(
-  nsIComponentManager compMgr,
-  nsIFile fileSpec,
-  componentsArray
-);
- -
Parameters
- -
-
compMgr
-
The {{ interface("nsIComponentManager") }} instance to use for managing the component.
-
fileSpec
-
An {{ interface("nsIFile") }} instance for... what?
-
componentsArray
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The array of components passed to generateModule().
-
- -

This function doesn't need to return a value.

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Examples

- -

defineLazyGetter

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var myServices = {};
-Cu.import('resource://gre/modules/XPCOMUtils.jsm');
-
-//set it up
-XPCOMUtils.defineLazyGetter(myServices, 'as', function () { return Cc['@mozilla.org/alerts-service;1'].getService(Ci.nsIAlertsService) });
-
-//when you need to use it
-myServices.as.showAlertNotification('chrome://branding/content/icon64.png', 'this was lazyloaded', 'this is a notification from myServices.as', null, null);
- -

See also

- - -- cgit v1.2.3-54-g00ecf