juce::TemporaryFile Class Reference

Manages a temporary file, which will be deleted when this object is deleted. More...

#include <juce_TemporaryFile.h>

Collaboration diagram for juce::TemporaryFile:

Public Types
enum	OptionFlags {   useHiddenFile = 1,   putNumbersInBrackets = 2 }

Public Member Functions
	TemporaryFile (const File &targetFile, const File &temporaryFile)
	Creates a temporary file using an explicit filename. More...
	TemporaryFile (const File &targetFile, int optionFlags=0)
	Creates a temporary file in the same directory as a specified file. More...
	TemporaryFile (const String &suffix=String(), int optionFlags=0)
	Creates a randomly-named temporary file in the default temp directory. More...
	~TemporaryFile ()
	Destructor. More...
bool	deleteTemporaryFile () const
	Attempts to delete the temporary file, if it exists. More...
const File &	getFile () const noexcept
	Returns the temporary file. More...
const File &	getTargetFile () const noexcept
	Returns the target file that was specified in the constructor. More...
bool	overwriteTargetFileWithTemporary () const
	Tries to move the temporary file to overwrite the target file that was specified in the constructor. More...

Private Attributes
const File	targetFile
const File	temporaryFile

Detailed Description

Manages a temporary file, which will be deleted when this object is deleted.

This object is intended to be used as a stack based object, using its scope to make sure the temporary file isn't left lying around.

For example:

{
    File myTargetFile ("~/myfile.txt");
 
    // this will choose a file called something like "~/myfile_temp239348.txt"
    // which definitely doesn't exist at the time the constructor is called.
    TemporaryFile temp (myTargetFile);
 
    // create a stream to the temporary file, and write some data to it...
    if (auto out = std::unique_ptr<FileOutputStream> (temp.getFile().createOutputStream()))
    {
        out->write ( ...etc )
        out.reset(); // (deletes the stream)
 
        // ..now we've finished writing, this will rename the temp file to
        // make it replace the target file we specified above.
        bool succeeded = temp.overwriteTargetFileWithTemporary();
    }
 
    // ..and even if something went wrong and our overwrite failed,
    // as the TemporaryFile object goes out of scope here, it'll make sure
    // that the temp file gets deleted.
}

See also

File, FileOutputStream

@tags{Core}

Member Enumeration Documentation

OptionFlags

enum juce::TemporaryFile::OptionFlags

Enumerator
useHiddenFile	Indicates that the temporary file should be hidden - i.e. its name should start with a dot.
putNumbersInBrackets	Indicates that when numbers are appended to make sure the file is unique, they should go in brackets rather than just being appended (see File::getNonexistentSibling() )

Constructor & Destructor Documentation

TemporaryFile() [1/3]

juce::TemporaryFile::TemporaryFile	(	const String &	suffix = String(),
		int	optionFlags = 0
	)

Creates a randomly-named temporary file in the default temp directory.

Parameters

suffix	a file suffix to use for the file
optionFlags	a combination of the values listed in the OptionFlags enum The file will not be created until you write to it. And remember that when this object is deleted, the file will also be deleted!

TemporaryFile() [2/3]

juce::TemporaryFile::TemporaryFile	(	const File &	targetFile,
		int	optionFlags = 0
	)

Creates a temporary file in the same directory as a specified file.

This is useful if you have a file that you want to overwrite, but don't want to harm the original file if the write operation fails. You can use this to create a temporary file next to the target file, then write to the temporary file, and finally use overwriteTargetFileWithTemporary() to replace the target file with the one you've just written.

This class won't create any files until you actually write to them. And remember that when this object is deleted, the temporary file will also be deleted!

Parameters

targetFile	the file that you intend to overwrite - the temporary file will be created in the same directory as this
optionFlags	a combination of the values listed in the OptionFlags enum

TemporaryFile() [3/3]

juce::TemporaryFile::TemporaryFile	(	const File &	targetFile,
		const File &	temporaryFile
	)

Creates a temporary file using an explicit filename.

The other constructors are a better choice than this one, unless for some reason you need to explicitly specify the temporary file you want to use.

Parameters

targetFile	the file that you intend to overwrite
temporaryFile	the temporary file to be used

~TemporaryFile()

juce::TemporaryFile::~TemporaryFile

(

)

Destructor.

When this object is deleted it will make sure that its temporary file is also deleted! If the operation fails, it'll throw an assertion in debug mode.

Member Function Documentation

deleteTemporaryFile()

bool juce::TemporaryFile::deleteTemporaryFile

(

)

const

Attempts to delete the temporary file, if it exists.

Returns

true if the file is successfully deleted (or if it didn't exist).

getFile()

const File& juce::TemporaryFile::getFile ( ) const

inlinenoexcept

Returns the temporary file.

getTargetFile()

const File& juce::TemporaryFile::getTargetFile ( ) const

inlinenoexcept

Returns the target file that was specified in the constructor.

overwriteTargetFileWithTemporary()

bool juce::TemporaryFile::overwriteTargetFileWithTemporary

(

)

const

Tries to move the temporary file to overwrite the target file that was specified in the constructor.

If you used the constructor that specified a target file, this will attempt to replace that file with the temporary one.

Before calling this, make sure:

• that you've actually written to the temporary file
• that you've closed any open streams that you were using to write to it
• and that you don't have any streams open to the target file, which would prevent it being overwritten

If the file move succeeds, this returns true, and the temporary file will have disappeared. If it fails, the temporary file will probably still exist, but will be deleted when this object is destroyed.

Member Data Documentation

targetFile

const File juce::TemporaryFile::targetFile

private

temporaryFile

const File juce::TemporaryFile::temporaryFile

private

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The documentation for this class was generated from the following file:

• juce_TemporaryFile.h