nsIInstallLocation Interface

 Interface representing a location where extensions, themes etc are
 installed.

[scriptable, uuid(32a74707-ec7c-af19-f4d8-d0cd8cb6a948)]

Constants

 Constants representing priority of some default Install Locations.
 XXXben - priority ranking of user-level items vs. global-level items
          here is debatable. Should app-system-global trump
          xre-system-user?
 You should not use the exact values here, you should offset from
 these values each time you create a new Install Location. Offsetting
 can be brittle but you should know what Install Locations are being
 defined for your own application.

const unsigned long PRIORITY_APP_PROFILE = 0

const unsigned long PRIORITY_APP_SYSTEM_USER = 10

const unsigned long PRIORITY_XRE_SYSTEM_USER = 100

const unsigned long PRIORITY_APP_SYSTEM_GLOBAL = 1000

const unsigned long PRIORITY_XRE_SYSTEM_GLOBAL = 10000

Attributes

 Whether or not the user can write to the Install Location with the
 current access privileges. This is different from restricted because
 it's not whether or not the location *might* be restricted, it's
 whether or not it actually *is* restricted right now.

readonly attribute boolean canAccess

 An enumeration of nsIFiles for:
 - locations that contain items
 - potential dropped-in XPIs
 Note: This enumeration resolves Text Links to the directories they
       refer to.

readonly attribute nsIDirectoryEnumerator itemLocations

 The file system location where items live. Items can be dropped in
 at this location. Can be null for Install Locations that don't have
 a file system presence.
 Note: This is a clone of the actual location which the caller can
       modify freely.

readonly attribute nsIFile location

 The string identifier of this Install Location

readonly attribute AString name

 The priority level of this Install Location in loading.

readonly attribute long priority

 Whether or not this Install Location is on an area of the file system
 that could be restricted on a restricted-access account, regardless
 of whether or not the location is restricted with the current user
 privileges.

readonly attribute boolean restricted

Methods

 Retrieves the GUID for an item at the specified location.
 @param   file
          The location where an item might live.
 @returns The ID for an item that might live at the location specified.

 N.B. This function makes no promises about whether or not this path is
      actually maintained by this Install Location.

AString getIDForLocation(in nsIFile file)

 Gets a nsIFile object for a file within an item's directory structure.
 @param   id
          The GUID of the item.
 @param   path
          The path to the file beneath an Extension's directory
 @returns A file object at the requested location. The file does not
          necessarily have to exist.

nsIFile getItemFile(in AString id, in AString path)

 Gets the directory that contains an item.
 @param   id
          The GUID of the item.
 @returns The location of the item.

nsIFile getItemLocation(in AString id)

 Returns the most recently staged package (e.g. the last XPI or JAR in a
 directory) for an item and removes items that do not qualify.

 @param   id
          The ID of the staged package
 @returns an nsIFile if the package exists otherwise null.

nsIFile getStageFile(in AString id)

 Determines whether or not an item's resources are managed by the Extension
 System or by some other user or process. For example, items linked to by
 text links are managed by the user, and items linked to from Registry
 Install Locations are usually managed by other applications or installers.

 @param   id
          The GUID of the item.
 @returns true if the item's resources are managed independently of the
          Extension System, false otherwise.

boolean itemIsManagedIndependently(in AString id)

 Removes a file from the stage. This cleans up the stage if there is nothing
 else left after the remove operation.

 @param   file
          The file to remove.

void removeFile(in nsIFile file)

 Stages the specified file by copying it to some location from where it
 can be retrieved later to complete installation.

 @param   file
          The file to stage
 @param   id
          The GUID of the item the file represents
 @returns The staged file

nsIFile stageFile(in nsIFile file, in AString id)