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An incremental download object attempts to fetch a file piecemeal over time in an effort to minimize network bandwidth usage. More...
|void||init (in nsIURI uri, in nsIFile destination, in long chunkSize, in long intervalInSeconds)|
|Initialize the incremental download object. |
|void||start (in nsIRequestObserver observer, in nsISupports ctxt)|
|Start the incremental download. |
|Indicates whether the request is pending. |
|void||cancel (in nsresult aStatus)|
|Cancels the current request. |
|Suspends the current request. |
|Resumes the current request. |
|readonly attribute nsIURI||URI|
|The URI being fetched. |
|readonly attribute nsIURI||finalURI|
|The URI being fetched after any redirects have been followed. |
|readonly attribute nsIFile||destination|
|The file where the download is being written. |
|readonly attribute long long||totalSize|
|The total number of bytes for the requested file. |
|readonly attribute long long||currentSize|
|The current number of bytes downloaded so far. |
|readonly attribute AUTF8String||name|
|The name of the request. |
|readonly attribute nsresult||status|
|The error status associated with the request. |
|The load group of this request. |
|The load flags of this request. |
|const unsigned long||LOAD_NORMAL = 0|
|No special load flags: |
|const unsigned long||LOAD_BACKGROUND = 1 << 0|
|Don't deliver status notifications to the nsIProgressEventSink, or keep this load from completing the nsILoadGroup it may belong to. |
|const unsigned long||INHIBIT_CACHING = 1 << 7|
|This flag prevents caching of any kind. |
|const unsigned long||INHIBIT_PERSISTENT_CACHING = 1 << 8|
|This flag prevents caching on disk (or other persistent media), which may be needed to preserve privacy. |
|const unsigned long||LOAD_BYPASS_CACHE = 1 << 9|
|Force an end-to-end download of content data from the origin server. |
|const unsigned long||LOAD_FROM_CACHE = 1 << 10|
|Load from the cache, bypassing protocol specific validation logic. |
|const unsigned long||VALIDATE_ALWAYS = 1 << 11|
|The following flags control the frequency of cached content validation when neither LOAD_BYPASS_CACHE or LOAD_FROM_CACHE are set. |
|const unsigned long||VALIDATE_NEVER = 1 << 12|
|const unsigned long||VALIDATE_ONCE_PER_SESSION = 1 << 13|
An incremental download object attempts to fetch a file piecemeal over time in an effort to minimize network bandwidth usage.
Canceling a background download does not cause the file on disk to be deleted.
Cancels the current request.
This will close any open input or output streams and terminate any async requests. Users should normally pass NS_BINDING_ABORTED, although other errors may also be passed. The error passed in will become the value of the status attribute.
|aStatus||the reason for canceling this request.|
NOTE: most nsIRequest implementations expect aStatus to be a failure code; however, some implementations may allow aStatus to be a success code such as NS_OK. In general, aStatus should be a failure code.
|void nsIIncrementalDownload::init||(||in nsIURI||uri,|
Initialize the incremental download object.
If the destination file already exists, then only the remaining portion of the file will be fetched.
NOTE: The downloader will create the destination file if it does not already exist. It will create the file with the permissions 0600 if needed. To affect the permissions of the file, consumers of this interface may create an empty file at the specified destination prior to starting the incremental download.
NOTE: Since this class may create a temporary file at the specified destination, it is advisable for the consumer of this interface to specify a file name for the destination that would not tempt the user into double-clicking it. For example, it might be wise to append a file extension like ".part" to the end of the destination to protect users from accidentally running "blah.exe" before it is a complete file.
|uri||The URI to fetch.|
|destination||The location where the file is to be stored.|
|chunkSize||The size of the chunks to fetch. A non-positive value results in the default chunk size being used.|
|intervalInSeconds||The amount of time to wait between fetching chunks. Pass a negative to use the default interval, or 0 to fetch the remaining part of the file in one chunk.|
Indicates whether the request is pending.
nsIRequest::isPending is true when there is an outstanding asynchronous event that will make the request no longer be pending. Requests do not necessarily start out pending; in some cases, requests have to be explicitly initiated (e.g. nsIChannel implementations are only pending once asyncOpen returns successfully).
Requests can become pending multiple times during their lifetime.
Resumes the current request.
This may have the effect of re-opening any underlying transport and will resume the delivery of data to any open streams.
Start the incremental download.
|observer||An observer to be notified of various events. OnStartRequest is called when finalURI and totalSize have been determined or when an error occurs. OnStopRequest is called when the file is completely downloaded or when an error occurs. If this object implements nsIProgressEventSink, then its OnProgress method will be called as data is written to the destination file. If this object implements nsIInterfaceRequestor, then it will be assigned as the underlying channel's notification callbacks, which allows it to provide a nsIAuthPrompt implementation if needed by the channel, for example.|
|ctxt||User defined object forwarded to the observer's methods.|
Suspends the current request.
This may have the effect of closing any underlying transport (in order to free up resources), although any open streams remain logically opened and will continue delivering data when the transport is resumed.
NOTE: some implementations are unable to immediately suspend, and may continue to deliver events already posted to an event queue. In general, callers should be capable of handling events even after suspending a request.
The following flags control the frequency of cached content validation when neither LOAD_BYPASS_CACHE or LOAD_FROM_CACHE are set.
By default, cached content is automatically validated if necessary before reuse.
VALIDATE_ALWAYS forces validation of any cached content independent of its expiration time.
VALIDATE_NEVER disables validation of expired content.
VALIDATE_ONCE_PER_SESSION disables validation of expired content, provided it has already been validated (at least once) since the start of this session.
NOTE TO IMPLEMENTORS: These flags are intended for normal browsing, and they should therefore not apply to content that must be validated before each use. Consider, for example, a HTTP response with a "Cache-control: no-cache" header. According to RFC2616, this response must be validated before it can be taken from a cache. Breaking this requirement could result in incorrect and potentially undesirable side-effects.