OpenShot Library | libopenshot-audio  0.1.9
juce_TemporaryFile.h
1 
2 /** @weakgroup juce_core-files
3  * @{
4  */
5 /*
6  ==============================================================================
7 
8  This file is part of the JUCE library.
9  Copyright (c) 2017 - ROLI Ltd.
10 
11  JUCE is an open source library subject to commercial or open-source
12  licensing.
13 
14  The code included in this file is provided under the terms of the ISC license
15  http://www.isc.org/downloads/software-support-policy/isc-license. Permission
16  To use, copy, modify, and/or distribute this software for any purpose with or
17  without fee is hereby granted provided that the above copyright notice and
18  this permission notice appear in all copies.
19 
20  JUCE IS PROVIDED "AS IS" WITHOUT ANY WARRANTY, AND ALL WARRANTIES, WHETHER
21  EXPRESSED OR IMPLIED, INCLUDING MERCHANTABILITY AND FITNESS FOR PURPOSE, ARE
22  DISCLAIMED.
23 
24  ==============================================================================
25 */
26 
27 namespace juce
28 {
29 
30 //==============================================================================
31 /**
32  Manages a temporary file, which will be deleted when this object is deleted.
33 
34  This object is intended to be used as a stack based object, using its scope
35  to make sure the temporary file isn't left lying around.
36 
37  For example:
38 
39  @code
40  {
41  File myTargetFile ("~/myfile.txt");
42 
43  // this will choose a file called something like "~/myfile_temp239348.txt"
44  // which definitely doesn't exist at the time the constructor is called.
45  TemporaryFile temp (myTargetFile);
46 
47  // create a stream to the temporary file, and write some data to it...
48  if (auto out = std::unique_ptr<FileOutputStream> (temp.getFile().createOutputStream()))
49  {
50  out->write ( ...etc )
51  out.reset(); // (deletes the stream)
52 
53  // ..now we've finished writing, this will rename the temp file to
54  // make it replace the target file we specified above.
55  bool succeeded = temp.overwriteTargetFileWithTemporary();
56  }
57 
58  // ..and even if something went wrong and our overwrite failed,
59  // as the TemporaryFile object goes out of scope here, it'll make sure
60  // that the temp file gets deleted.
61  }
62  @endcode
63 
64  @see File, FileOutputStream
65 
66  @tags{Core}
67 */
69 {
70 public:
71  //==============================================================================
73  {
74  useHiddenFile = 1, /**< Indicates that the temporary file should be hidden -
75  i.e. its name should start with a dot. */
76  putNumbersInBrackets = 2 /**< Indicates that when numbers are appended to make sure
77  the file is unique, they should go in brackets rather
78  than just being appended (see File::getNonexistentSibling() )*/
79  };
80 
81  //==============================================================================
82  /** Creates a randomly-named temporary file in the default temp directory.
83 
84  @param suffix a file suffix to use for the file
85  @param optionFlags a combination of the values listed in the OptionFlags enum
86  The file will not be created until you write to it. And remember that when
87  this object is deleted, the file will also be deleted!
88  */
89  TemporaryFile (const String& suffix = String(),
90  int optionFlags = 0);
91 
92  /** Creates a temporary file in the same directory as a specified file.
93 
94  This is useful if you have a file that you want to overwrite, but don't
95  want to harm the original file if the write operation fails. You can
96  use this to create a temporary file next to the target file, then
97  write to the temporary file, and finally use overwriteTargetFileWithTemporary()
98  to replace the target file with the one you've just written.
99 
100  This class won't create any files until you actually write to them. And remember
101  that when this object is deleted, the temporary file will also be deleted!
102 
103  @param targetFile the file that you intend to overwrite - the temporary
104  file will be created in the same directory as this
105  @param optionFlags a combination of the values listed in the OptionFlags enum
106  */
107  TemporaryFile (const File& targetFile,
108  int optionFlags = 0);
109 
110  /** Creates a temporary file using an explicit filename.
111  The other constructors are a better choice than this one, unless for some reason
112  you need to explicitly specify the temporary file you want to use.
113 
114  @param targetFile the file that you intend to overwrite
115  @param temporaryFile the temporary file to be used
116  */
117  TemporaryFile (const File& targetFile,
118  const File& temporaryFile);
119 
120  /** Destructor.
121 
122  When this object is deleted it will make sure that its temporary file is
123  also deleted! If the operation fails, it'll throw an assertion in debug
124  mode.
125  */
126  ~TemporaryFile();
127 
128  //==============================================================================
129  /** Returns the temporary file. */
130  const File& getFile() const noexcept { return temporaryFile; }
131 
132  /** Returns the target file that was specified in the constructor. */
133  const File& getTargetFile() const noexcept { return targetFile; }
134 
135  /** Tries to move the temporary file to overwrite the target file that was
136  specified in the constructor.
137 
138  If you used the constructor that specified a target file, this will attempt
139  to replace that file with the temporary one.
140 
141  Before calling this, make sure:
142  - that you've actually written to the temporary file
143  - that you've closed any open streams that you were using to write to it
144  - and that you don't have any streams open to the target file, which would
145  prevent it being overwritten
146 
147  If the file move succeeds, this returns true, and the temporary file will
148  have disappeared. If it fails, the temporary file will probably still exist,
149  but will be deleted when this object is destroyed.
150  */
151  bool overwriteTargetFileWithTemporary() const;
152 
153  /** Attempts to delete the temporary file, if it exists.
154  @returns true if the file is successfully deleted (or if it didn't exist).
155  */
156  bool deleteTemporaryFile() const;
157 
158 
159 private:
160  //==============================================================================
161  const File temporaryFile, targetFile;
162 
163  JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (TemporaryFile)
164 };
165 
166 } // namespace juce
167 
168 /** @}*/
Manages a temporary file, which will be deleted when this object is deleted.
#define JUCE_API
This macro is added to all JUCE public class declarations.
const File & getFile() const noexcept
Returns the temporary file.
const File & getTargetFile() const noexcept
Returns the target file that was specified in the constructor.
The JUCE String class!
Definition: juce_String.h:42
Represents a local file or directory.
Definition: juce_File.h:44