Package org.gnome.glib

Class MappedFile

java.lang.Object

org.javagi.base.ProxyInstance

org.gnome.glib.MappedFile

All Implemented Interfaces:

Proxy

@Generated("io.github.jwharm.JavaGI")
public class MappedFile
extends ProxyInstance

The GMappedFile represents a file mapping created with g_mapped_file_new(). It has only private members and should not be accessed directly.

Constructor Summary

Constructors

Constructor	Description
MappedFile(MemorySegment address)	Create a MappedFile proxy instance for the provided memory address.
MappedFile(String filename, boolean writable)	Maps a file into memory.

Method Summary

Modifier and Type	Method	Description
void	free()	Deprecated. Use g_mapped_file_unref() instead.
static MappedFile	fromFd(int fd, boolean writable)	Maps a file into memory.
byte[]	getBytes()	Creates a new GBytes which references the data mapped from file. The mapped contents of the file must not be modified after creating this bytes object, because a GBytes should be immutable.
@Nullable String	getContents()	Returns the contents of a GMappedFile.
long	getLength()	Returns the length of the contents of a GMappedFile.
static @Nullable Type	getType()	Get the GType of the MappedFile class
MappedFile	ref()	Increments the reference count of this MappedFile by one.
void	unref()	Decrements the reference count of this MappedFile by one.

Methods inherited from class org.javagi.base.ProxyInstance

equals, handle, hashCode

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, toString, wait, wait, wait

Constructor Details

MappedFile

public MappedFile(MemorySegment address)

Create a MappedFile proxy instance for the provided memory address.

Parameters:

address - the memory address of the native object

MappedFile

public MappedFile(String filename,
 boolean writable)
           throws GErrorException

Maps a file into memory. On UNIX, this is using the mmap() function.

If writable is true, the mapped buffer may be modified, otherwise it is an error to modify the mapped buffer. Modifications to the buffer are not visible to other processes mapping the same file, and are not written back to the file.

Note that modifications of the underlying file might affect the contents of the GMappedFile. Therefore, mapping should only be used if the file will not be modified, or if all modifications of the file are done atomically (e.g. using g_file_set_contents()).

If filename is the name of an empty, regular file, the function will successfully return an empty GMappedFile. In other cases of size 0 (e.g. device files such as /dev/null), error will be set to the GFileError value FileError.INVAL.

Parameters:

filename - The path of the file to load, in the GLib filename encoding

writable - whether the mapping should be writable

Throws:

GErrorException - see GError

Since:

2.8

Method Details

getType

public static @Nullable Type getType()

Get the GType of the MappedFile class

Returns:

the GType

fromFd

public static MappedFile fromFd(int fd,
 boolean writable)
                         throws GErrorException

Maps a file into memory. On UNIX, this is using the mmap() function.

If writable is true, the mapped buffer may be modified, otherwise it is an error to modify the mapped buffer. Modifications to the buffer are not visible to other processes mapping the same file, and are not written back to the file.

Note that modifications of the underlying file might affect the contents of the GMappedFile. Therefore, mapping should only be used if the file will not be modified, or if all modifications of the file are done atomically (e.g. using g_file_set_contents()).

Parameters:

fd - The file descriptor of the file to load

writable - whether the mapping should be writable

Returns:

a newly allocated GMappedFile which must be unref'd with g_mapped_file_unref(), or null if the mapping failed.

Throws:

GErrorException - see GError

Since:

2.32

free

@Deprecated
public void free()

Deprecated.

Use g_mapped_file_unref() instead.

This call existed before GMappedFile had refcounting and is currently exactly the same as g_mapped_file_unref().

Since:

2.8

getBytes

public byte[] getBytes()

Creates a new GBytes which references the data mapped from file. The mapped contents of the file must not be modified after creating this bytes object, because a GBytes should be immutable.

Returns:

A newly allocated GBytes referencing data from this MappedFile

Since:

2.34

getContents

public @Nullable String getContents()

Returns the contents of a GMappedFile.

Note that the contents may not be zero-terminated, even if the GMappedFile is backed by a text file.

If the file is empty then null is returned.

Returns:

the contents of file, or null.

Since:

2.8

getLength

public long getLength()

Returns the length of the contents of a GMappedFile.

Returns:

the length of the contents of file.

Since:

2.8

ref

public MappedFile ref()

Increments the reference count of this MappedFile by one. It is safe to call this function from any thread.

Returns:

the passed in GMappedFile.

Since:

2.22

unref

public void unref()

Decrements the reference count of this MappedFile by one. If the reference count drops to 0, unmaps the buffer of this MappedFile and frees it.

It is safe to call this function from any thread.

Since 2.22