1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
|
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#include "nsISupports.idl"
interface nsIArray;
interface nsIBackgroundFileSaverObserver;
interface nsIFile;
/**
* Allows saving data to a file, while handling all the input/output on a
* background thread, including the initial file name assignment and any
* subsequent renaming of the target file.
*
* This interface is designed for file downloads. Generally, they start in the
* temporary directory, while the user is selecting the final name. Then, they
* are moved to the chosen target directory with a ".part" extension appended to
* the file name. Finally, they are renamed when the download is completed.
*
* Components implementing both nsIBackgroundFileSaver and nsIStreamListener
* allow data to be fed using an implementation of OnDataAvailable that never
* blocks the calling thread. They suspend the request that drives the stream
* listener in case too much data is being fed, and resume it when the data has
* been written. Calling OnStopRequest does not necessarily close the target
* file, and the Finish method must be called to complete the operation.
*
* Components implementing both nsIBackgroundFileSaver and nsIAsyncOutputStream
* allow data to be fed directly to the non-blocking output stream, that however
* may return NS_BASE_STREAM_WOULD_BLOCK in case too much data is being fed.
* Closing the output stream does not necessarily close the target file, and the
* Finish method must be called to complete the operation.
*
* @remarks Implementations may require the consumer to always call Finish. If
* the object reference is released without calling Finish, a memory
* leak may occur, and the target file might be kept locked. All
* public methods of the interface may only be called from the main
* thread.
*/
[scriptable, uuid(c43544a4-682c-4262-b407-2453d26e660d)]
interface nsIBackgroundFileSaver : nsISupports
{
/**
* This observer receives notifications when the target file name changes and
* when the operation completes, successfully or not.
*
* @remarks A strong reference to the observer is held. Notification events
* are dispatched to the thread that created the object that
* implements nsIBackgroundFileSaver.
*/
attribute nsIBackgroundFileSaverObserver observer;
/**
* An nsIArray of nsIX509CertList, representing a chain of X.509 signatures on
* the downloaded file. Each list may belong to a different signer and contain
* certificates all the way up to the root.
*
* @throws NS_ERROR_NOT_AVAILABLE
* In case this is called before the onSaveComplete method has been
* called to notify success, or enableSignatureInfo has not been
* called.
*/
readonly attribute nsIArray signatureInfo;
/**
* The SHA-256 hash, in raw bytes, associated with the data that was saved.
*
* In case the enableAppend method has been called, the hash computation
* includes the contents of the existing file, if any.
*
* @throws NS_ERROR_NOT_AVAILABLE
* In case the enableSha256 method has not been called, or before the
* onSaveComplete method has been called to notify success.
*/
readonly attribute ACString sha256Hash;
/**
* Instructs the component to compute the signatureInfo of the target file,
* and make it available in the signatureInfo property.
*
* @remarks This must be set on the main thread before the first call to
* setTarget.
*/
void enableSignatureInfo();
/**
* Instructs the component to compute the SHA-256 hash of the target file, and
* make it available in the sha256Hash property.
*
* @remarks This must be set on the main thread before the first call to
* setTarget.
*/
void enableSha256();
/**
* Instructs the component to append data to the initial target file, that
* will be specified by the first call to the setTarget method, instead of
* overwriting the file.
*
* If the initial target file does not exist, this method has no effect.
*
* @remarks This must be set on the main thread before the first call to
* setTarget.
*/
void enableAppend();
/**
* Sets the name of the output file to be written. The target can be changed
* after data has already been fed, in which case the existing file will be
* moved to the new destination.
*
* In case the specified file already exists, and this method is called for
* the first time, the file may be either overwritten or appended to, based on
* whether the enableAppend method was called. Subsequent calls always
* overwrite the specified target file with the previously saved data.
*
* No file will be written until this function is called at least once. It's
* recommended not to feed any data until the output file is set.
*
* If an input/output error occurs with the specified file, the save operation
* fails. Failure is notified asynchronously through the observer.
*
* @param aTarget
* New output file to be written.
* @param aKeepPartial
* Indicates whether aFile should be kept as partially completed,
* rather than deleted, if the operation fails or is canceled. This is
* generally set for downloads that use temporary ".part" files.
*/
void setTarget(in nsIFile aTarget, in bool aKeepPartial);
/**
* Terminates access to the output file, then notifies the observer with the
* specified status code. A failure code will force the operation to be
* canceled, in which case the output file will be deleted if requested.
*
* This forces the involved streams to be closed, thus no more data should be
* fed to the component after this method has been called.
*
* This is the last method that should be called on this object, and the
* target file name cannot be changed anymore after this method has been
* called. Conversely, before calling this method, the file can still be
* renamed even if all the data has been fed.
*
* @param aStatus
* Result code that determines whether the operation should succeed or
* be canceled, and is notified to the observer. If the operation
* fails meanwhile for other reasons, or the observer has been already
* notified of completion, this status code is ignored.
*/
void finish(in nsresult aStatus);
};
[scriptable, uuid(ee7058c3-6e54-4411-b76b-3ce87b76fcb6)]
interface nsIBackgroundFileSaverObserver : nsISupports
{
/**
* Called when the name of the output file has been determined. This function
* may be called more than once if the target file is renamed while saving.
*
* @param aSaver
* Reference to the object that raised the notification.
* @param aTarget
* Name of the file that is being written.
*/
void onTargetChange(in nsIBackgroundFileSaver aSaver, in nsIFile aTarget);
/**
* Called when the operation completed, and the target file has been closed.
* If the operation succeeded, the target file is ready to be used, otherwise
* it might have been already deleted.
*
* @param aSaver
* Reference to the object that raised the notification.
* @param aStatus
* Result code that determines whether the operation succeeded or
* failed, as well as the failure reason.
*/
void onSaveComplete(in nsIBackgroundFileSaver aSaver, in nsresult aStatus);
};
|
