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The file management API.(3) libmtp The file management API.(3)

NAME

libmtp - The file management API.

Functions


LIBMTP_file_t * LIBMTP_new_file_t (void)
 
void LIBMTP_destroy_file_t (LIBMTP_file_t *)
 
char const * LIBMTP_Get_Filetype_Description (LIBMTP_filetype_t)
 
LIBMTP_file_t * LIBMTP_Get_Filelisting (LIBMTP_mtpdevice_t *)
 
LIBMTP_file_t * LIBMTP_Get_Filelisting_With_Callback (LIBMTP_mtpdevice_t *, LIBMTP_progressfunc_t const, void const *const)
 
LIBMTP_file_t * LIBMTP_Get_Files_And_Folders (LIBMTP_mtpdevice_t *, uint32_t const, uint32_t const)
 
LIBMTP_file_t * LIBMTP_Get_Filemetadata (LIBMTP_mtpdevice_t *, uint32_t const)
 
int LIBMTP_Get_File_To_File (LIBMTP_mtpdevice_t *, uint32_t, char const *const, LIBMTP_progressfunc_t const, void const *const)
 
int LIBMTP_Get_File_To_File_Descriptor (LIBMTP_mtpdevice_t *, uint32_t const, int const, LIBMTP_progressfunc_t const, void const *const)
 
int LIBMTP_Get_File_To_Handler (LIBMTP_mtpdevice_t *, uint32_t const, MTPDataPutFunc, void *, LIBMTP_progressfunc_t const, void const *const)
 
int LIBMTP_Send_File_From_File (LIBMTP_mtpdevice_t *, char const *const, LIBMTP_file_t *const, LIBMTP_progressfunc_t const, void const *const)
 
int LIBMTP_Send_File_From_File_Descriptor (LIBMTP_mtpdevice_t *, int const, LIBMTP_file_t *const, LIBMTP_progressfunc_t const, void const *const)
 
int LIBMTP_Send_File_From_Handler (LIBMTP_mtpdevice_t *, MTPDataGetFunc, void *, LIBMTP_file_t *const, LIBMTP_progressfunc_t const, void const *const)
 
int LIBMTP_Set_File_Name (LIBMTP_mtpdevice_t *, LIBMTP_file_t *, const char *)
 
LIBMTP_filesampledata_t * LIBMTP_new_filesampledata_t (void)
 
void LIBMTP_destroy_filesampledata_t (LIBMTP_filesampledata_t *)
 
int LIBMTP_Get_Representative_Sample_Format (LIBMTP_mtpdevice_t *, LIBMTP_filetype_t const, LIBMTP_filesampledata_t **)
 
int LIBMTP_Send_Representative_Sample (LIBMTP_mtpdevice_t *, uint32_t const, LIBMTP_filesampledata_t *)
 
int LIBMTP_Get_Representative_Sample (LIBMTP_mtpdevice_t *, uint32_t const, LIBMTP_filesampledata_t *)
 
int LIBMTP_Get_Thumbnail (LIBMTP_mtpdevice_t *, uint32_t const, unsigned char **data, unsigned int *size)
 
int LIBMTP_Read_Event (LIBMTP_mtpdevice_t *, LIBMTP_event_t *, uint32_t *)
 

Detailed Description

Function Documentation

void LIBMTP_destroy_file_t ( LIBMTP_file_t *file)

This destroys a file metadata structure and deallocates the memory used by it, including any strings. Never use a file metadata structure again after calling this function on it.
Parameters:
file the file metadata to destroy.
See also:
LIBMTP_new_file_t()
References LIBMTP_file_struct::filename.
Referenced by LIBMTP_Send_File_From_File_Descriptor(), and LIBMTP_Send_File_From_Handler().

void LIBMTP_destroy_filesampledata_t ( LIBMTP_filesampledata_t *sample)

This destroys a file sample metadata type.
Parameters:
sample the file sample metadata to be destroyed.
References LIBMTP_filesampledata_struct::data.

int LIBMTP_Get_File_To_File ( LIBMTP_mtpdevice_t *device, uint32_t constid, char const *constpath, LIBMTP_progressfunc_t constcallback, void const *constdata)

This gets a file off the device to a local file identified by a filename.
Parameters:
device a pointer to the device to get the track from.
 
id the file ID of the file to retrieve.
 
path a filename to use for the retrieved file.
 
callback a progress indicator function or NULL to ignore.
 
data a user-defined pointer that is passed along to the progress function in order to pass along some user defined data to the progress updates. If not used, set this to NULL.
Returns:
0 if the transfer was successful, any other value means failure.
See also:
LIBMTP_Get_File_To_File_Descriptor()
References LIBMTP_Get_File_To_File_Descriptor().
Referenced by LIBMTP_Get_Track_To_File().

int LIBMTP_Get_File_To_File_Descriptor ( LIBMTP_mtpdevice_t *device, uint32_t constid, int constfd, LIBMTP_progressfunc_t constcallback, void const *constdata)

This gets a file off the device to a file identified by a file descriptor.
This function can potentially be used for streaming files off the device for playback or broadcast for example, by downloading the file into a stream sink e.g. a socket.
Parameters:
device a pointer to the device to get the file from.
 
id the file ID of the file to retrieve.
 
fd a local file descriptor to write the file to.
 
callback a progress indicator function or NULL to ignore.
 
data a user-defined pointer that is passed along to the progress function in order to pass along some user defined data to the progress updates. If not used, set this to NULL.
Returns:
0 if the transfer was successful, any other value means failure.
See also:
LIBMTP_Get_File_To_File()
References LIBMTP_mtpdevice_struct::params, and LIBMTP_mtpdevice_struct::usbinfo.
Referenced by LIBMTP_Get_File_To_File(), and LIBMTP_Get_Track_To_File_Descriptor().

int LIBMTP_Get_File_To_Handler ( LIBMTP_mtpdevice_t *device, uint32_t constid, MTPDataPutFuncput_func, void *priv, LIBMTP_progressfunc_t constcallback, void const *constdata)

This gets a file off the device and calls put_func with chunks of data
Parameters:
device a pointer to the device to get the file from.
 
id the file ID of the file to retrieve.
 
put_func the function to call when we have data.
 
priv the user-defined pointer that is passed to put_func.
 
callback a progress indicator function or NULL to ignore.
 
data a user-defined pointer that is passed along to the progress function in order to pass along some user defined data to the progress updates. If not used, set this to NULL.
Returns:
0 if the transfer was successful, any other value means failure.
References LIBMTP_mtpdevice_struct::params, and LIBMTP_mtpdevice_struct::usbinfo.
Referenced by LIBMTP_Get_Track_To_Handler().

LIBMTP_file_t* LIBMTP_Get_Filelisting ( LIBMTP_mtpdevice_t *device)

THIS FUNCTION IS DEPRECATED. PLEASE UPDATE YOUR CODE IN ORDER NOT TO USE IT.
See also:
LIBMTP_Get_Filelisting_With_Callback()
References LIBMTP_Get_Filelisting_With_Callback().

LIBMTP_file_t* LIBMTP_Get_Filelisting_With_Callback ( LIBMTP_mtpdevice_t *device, LIBMTP_progressfunc_t constcallback, void const *constdata)

This returns a long list of all files available on the current MTP device. Folders will not be returned, but abstract entities like playlists and albums will show up as 'files'. Typical usage: 

LIBMTP_file_t *filelist;

filelist = LIBMTP_Get_Filelisting_With_Callback(device, callback, data);
while (filelist != NULL) {
  LIBMTP_file_t *tmp;

  // Do something on each element in the list here...
  tmp = filelist;
  filelist = filelist->next;
  LIBMTP_destroy_file_t(tmp);
}
If you want to group your file listing by storage (per storage unit) or arrange files into folders, you must dereference the storage_id and/or parent_id field of the returned LIBMTP_file_t struct. To arrange by folders or files you typically have to create the proper trees by calls to LIBMTP_Get_Storage() and/or LIBMTP_Get_Folder_List() first.
Parameters:
device a pointer to the device to get the file listing for.
 
callback a function to be called during the tracklisting retrieveal for displaying progress bars etc, or NULL if you don't want any callbacks.
 
data a user-defined pointer that is passed along to the progress function in order to pass along some user defined data to the progress updates. If not used, set this to NULL.
Returns:
a list of files that can be followed using the next field of the LIBMTP_file_t data structure. Each of the metadata tags must be freed after use, and may contain only partial metadata information, i.e. one or several fields may be NULL or 0.
See also:
LIBMTP_Get_Filemetadata()
References LIBMTP_file_struct::next, and LIBMTP_mtpdevice_struct::params.
Referenced by LIBMTP_Get_Filelisting().

LIBMTP_file_t* LIBMTP_Get_Filemetadata ( LIBMTP_mtpdevice_t *device, uint32_t constfileid)

This function retrieves the metadata for a single file off the device.
Do not call this function repeatedly! The file handles are linearly searched O(n) and the call may involve (slow) USB traffic, so use LIBMTP_Get_Filelisting() and cache the file, preferably as an efficient data structure such as a hash list.
Incidentally this function will return metadata for a folder (association) as well, but this is not a proper use of it, it is intended for file manipulation, not folder manipulation.
Parameters:
device a pointer to the device to get the file metadata from.
 
fileid the object ID of the file that you want the metadata for.
Returns:
a metadata entry on success or NULL on failure.
See also:
LIBMTP_Get_Filelisting()
References LIBMTP_mtpdevice_struct::cached, and LIBMTP_mtpdevice_struct::params.
Referenced by LIBMTP_Get_Files_And_Folders(), LIBMTP_Send_File_From_File_Descriptor(), LIBMTP_Send_File_From_Handler(), and LIBMTP_Set_Object_Filename().

LIBMTP_file_t* LIBMTP_Get_Files_And_Folders ( LIBMTP_mtpdevice_t *device, uint32_t conststorage, uint32_t constparent)

This function retrieves the contents of a certain folder with id parent on a certain storage on a certain device. The result contains both files and folders. The device used with this operations must have been opened with LIBMTP_Open_Raw_Device_Uncached() or it will fail.
NOTE: the request will always perform I/O with the device.
Parameters:
device a pointer to the MTP device to report info from.
 
storage a storage on the device to report info from. If 0 is passed in, the files for the given parent will be searched across all available storages.
 
parent the parent folder id.
References LIBMTP_mtpdevice_struct::cached, LIBMTP_Get_Filemetadata(), LIBMTP_file_struct::next, LIBMTP_mtpdevice_struct::params, and LIBMTP_mtpdevice_struct::usbinfo.

char const* LIBMTP_Get_Filetype_Description ( LIBMTP_filetype_tintype)

This helper function returns a textual description for a libmtp file type to be used in dialog boxes etc.
Parameters:
intype the libmtp internal filetype to get a description for.
Returns:
a string representing the filetype, this must NOT be free():ed by the caller!
References filemap_struct::description, and filemap_struct::id.

int LIBMTP_Get_Representative_Sample ( LIBMTP_mtpdevice_t *device, uint32_t constid, LIBMTP_filesampledata_t *sampledata)

This routine gets representative sample data for an object. This uses the RepresentativeSampleData property of the album, if the device supports it.
Parameters:
device a pointer to the device which the object is on.
 
id unique id of the object to get data for.
 
pointer to LIBMTP_filesampledata_t struct to receive data
Returns:
0 on success, any other value means failure.
See also:
LIBMTP_Send_Representative_Sample()
LIBMTP_Get_Representative_Sample_Format()
LIBMTP_Create_New_Album()
References LIBMTP_filesampledata_struct::data, LIBMTP_filesampledata_struct::duration, LIBMTP_filesampledata_struct::filetype, LIBMTP_filesampledata_struct::height, LIBMTP_mtpdevice_struct::params, LIBMTP_filesampledata_struct::size, and LIBMTP_filesampledata_struct::width.

int LIBMTP_Get_Representative_Sample_Format ( LIBMTP_mtpdevice_t *device, LIBMTP_filetype_t constfiletype, LIBMTP_filesampledata_t **sample)

This routine figures out whether a certain filetype supports representative samples (small thumbnail images) or not. This typically applies to JPEG files, MP3 files and Album abstract playlists, but in theory any filetype could support representative samples.
Parameters:
device a pointer to the device which is to be examined.
 
filetype the fileype to examine, and return the representative sample properties for.
 
sample this will contain a new sample type with the fields filled in with suitable default values. For example, the supported sample type will be set, the supported height and width will be set to max values if it is an image sample, and duration will also be given some suitable default value which should not be exceeded on audio samples. If the device does not support samples for this filetype, this pointer will be NULL. If it is not NULL, the user must destroy this struct with LIBMTP_destroy_filesampledata_t() after use.
Returns:
0 on success, any other value means failure.
See also:
LIBMTP_Send_Representative_Sample()
LIBMTP_Create_New_Album()
References LIBMTP_filesampledata_struct::duration, LIBMTP_filesampledata_struct::filetype, LIBMTP_filesampledata_struct::height, LIBMTP_new_filesampledata_t(), LIBMTP_mtpdevice_struct::params, LIBMTP_filesampledata_struct::size, and LIBMTP_filesampledata_struct::width.

int LIBMTP_Get_Thumbnail ( LIBMTP_mtpdevice_t *device, uint32_t constid, unsigned char **data, unsigned int *size)

Retrieve the thumbnail for a file.
Parameters:
device a pointer to the device to get the thumbnail from.
 
id the object ID of the file to retrieve the thumbnail for.
Returns:
0 on success, any other value means failure.
References LIBMTP_mtpdevice_struct::params.

LIBMTP_file_t* LIBMTP_new_file_t (void)

This creates a new file metadata structure and allocates memory for it. Notice that if you add strings to this structure they will be freed by the corresponding LIBMTP_destroy_file_t operation later, so be careful of using strdup() when assigning strings, e.g.: 

LIBMTP_file_t *file =  LIBMTP_new_file_t();
file->filename = strdup(namestr);
....
LIBMTP_destroy_file_t(file);
Returns:
a pointer to the newly allocated metadata structure.
See also:
LIBMTP_destroy_file_t()
References LIBMTP_file_struct::filename.

LIBMTP_filesampledata_t* LIBMTP_new_filesampledata_t (void)

This creates a new sample data metadata structure and allocates memory for it. Notice that if you add strings to this structure they will be freed by the corresponding LIBMTP_destroy_sampledata_t operation later, so be careful of using strdup() when assigning strings.
Returns:
a pointer to the newly allocated metadata structure.
See also:
LIBMTP_destroy_sampledata_t()
References LIBMTP_filesampledata_struct::height.
Referenced by LIBMTP_Get_Representative_Sample_Format().

int LIBMTP_Read_Event ( LIBMTP_mtpdevice_t *device, LIBMTP_event_t *event, uint32_t *out1)

To read events sent by the device, repeatedly call this function from a secondary thread until the return value is < 0.
Parameters:
device a pointer to the MTP device to poll for events.
 
event contains a pointer to be filled in with the event retrieved if the call is successful.
 
out1 contains the param1 value from the raw event.
Returns:
0 on success, any other value means the polling loop shall be terminated immediately for this session.
References LIBMTP_mtpdevice_struct::params.

int LIBMTP_Send_File_From_File ( LIBMTP_mtpdevice_t *device, char const *constpath, LIBMTP_file_t *constfiledata, LIBMTP_progressfunc_t constcallback, void const *constdata)

This function sends a local file to an MTP device. A filename and a set of metadata must be given as input.
Parameters:
device a pointer to the device to send the track to.
 
path the filename of a local file which will be sent.
 
filedata a file metadata set to be written along with the file. After this call the field filedata->item_id will contain the new file ID. Other fields such as the filedata->filename, filedata->parent_id or filedata->storage_id may also change during this operation due to device restrictions, so do not rely on the contents of this struct to be preserved in any way.
•
filedata->parent_id should be set to the parent (e.g. folder) to store this file in. If this is 0, the file will be stored in the root folder.
•
filedata->storage_id should be set to the desired storage (e.g. memory card or whatever your device presents) to store this file in. Setting this to 0 will store the file on the primary storage.
callback a progress indicator function or NULL to ignore.
 
data a user-defined pointer that is passed along to the progress function in order to pass along some user defined data to the progress updates. If not used, set this to NULL.
Returns:
0 if the transfer was successful, any other value means failure.
See also:
LIBMTP_Send_File_From_File_Descriptor()
LIBMTP_Delete_Object()
References LIBMTP_Send_File_From_File_Descriptor().

int LIBMTP_Send_File_From_File_Descriptor ( LIBMTP_mtpdevice_t *device, int constfd, LIBMTP_file_t *constfiledata, LIBMTP_progressfunc_t constcallback, void const *constdata)

This function sends a generic file from a file descriptor to an MTP device. A filename and a set of metadata must be given as input.
This can potentially be used for sending in a stream of unknown length. Send music files with LIBMTP_Send_Track_From_File_Descriptor()
Parameters:
device a pointer to the device to send the file to.
 
fd the filedescriptor for a local file which will be sent.
 
filedata a file metadata set to be written along with the file. After this call the field filedata->item_id will contain the new file ID. Other fields such as the filedata->filename, filedata->parent_id or filedata->storage_id may also change during this operation due to device restrictions, so do not rely on the contents of this struct to be preserved in any way.
•
filedata->parent_id should be set to the parent (e.g. folder) to store this file in. If this is 0, the file will be stored in the root folder.
•
filedata->storage_id should be set to the desired storage (e.g. memory card or whatever your device presents) to store this file in. Setting this to 0 will store the file on the primary storage.
callback a progress indicator function or NULL to ignore.
 
data a user-defined pointer that is passed along to the progress function in order to pass along some user defined data to the progress updates. If not used, set this to NULL.
Returns:
0 if the transfer was successful, any other value means failure.
See also:
LIBMTP_Send_File_From_File()
LIBMTP_Send_Track_From_File_Descriptor()
LIBMTP_Delete_Object()
References LIBMTP_file_struct::filesize, LIBMTP_file_struct::item_id, LIBMTP_destroy_file_t(), LIBMTP_Get_Filemetadata(), LIBMTP_mtpdevice_struct::params, LIBMTP_file_struct::parent_id, LIBMTP_file_struct::storage_id, and LIBMTP_mtpdevice_struct::usbinfo.
Referenced by LIBMTP_Send_File_From_File(), and LIBMTP_Send_Track_From_File_Descriptor().

int LIBMTP_Send_File_From_Handler ( LIBMTP_mtpdevice_t *device, MTPDataGetFuncget_func, void *priv, LIBMTP_file_t *constfiledata, LIBMTP_progressfunc_t constcallback, void const *constdata)

This function sends a generic file from a handler function to an MTP device. A filename and a set of metadata must be given as input.
This can potentially be used for sending in a stream of unknown length. Send music files with LIBMTP_Send_Track_From_Handler()
Parameters:
device a pointer to the device to send the file to.
 
get_func the function to call to get data to write
 
priv a user-defined pointer that is passed along to get_func. If not used, this is set to NULL.
 
filedata a file metadata set to be written along with the file. After this call the field filedata->item_id will contain the new file ID. Other fields such as the filedata->filename, filedata->parent_id or filedata->storage_id may also change during this operation due to device restrictions, so do not rely on the contents of this struct to be preserved in any way.
•
filedata->parent_id should be set to the parent (e.g. folder) to store this file in. If this is 0, the file will be stored in the root folder.
•
filedata->storage_id should be set to the desired storage (e.g. memory card or whatever your device presents) to store this file in. Setting this to 0 will store the file on the primary storage.
callback a progress indicator function or NULL to ignore.
 
data a user-defined pointer that is passed along to the progress function in order to pass along some user defined data to the progress updates. If not used, set this to NULL.
Returns:
0 if the transfer was successful, any other value means failure.
See also:
LIBMTP_Send_File_From_File()
LIBMTP_Send_Track_From_File_Descriptor()
LIBMTP_Delete_Object()
References LIBMTP_file_struct::filesize, LIBMTP_file_struct::item_id, LIBMTP_destroy_file_t(), LIBMTP_Get_Filemetadata(), LIBMTP_mtpdevice_struct::params, LIBMTP_file_struct::parent_id, LIBMTP_file_struct::storage_id, and LIBMTP_mtpdevice_struct::usbinfo.
Referenced by LIBMTP_Send_Track_From_Handler().

int LIBMTP_Send_Representative_Sample ( LIBMTP_mtpdevice_t *device, uint32_t constid, LIBMTP_filesampledata_t *sampledata)

This routine sends representative sample data for an object. This uses the RepresentativeSampleData property of the album, if the device supports it. The data should be of a format acceptable to the player (for iRiver and Creative, this seems to be JPEG) and must not be too large. (for a Creative, max seems to be about 20KB.) Check by calling LIBMTP_Get_Representative_Sample_Format() to get maximum size, dimensions, etc..
Parameters:
device a pointer to the device which the object is on.
 
id unique id of the object to set artwork for.
 
pointer to LIBMTP_filesampledata_t struct containing data
Returns:
0 on success, any other value means failure.
See also:
LIBMTP_Get_Representative_Sample()
LIBMTP_Get_Representative_Sample_Format()
LIBMTP_Create_New_Album()
References LIBMTP_filesampledata_struct::data, LIBMTP_filesampledata_struct::duration, LIBMTP_filesampledata_struct::filetype, LIBMTP_filesampledata_struct::height, LIBMTP_mtpdevice_struct::params, LIBMTP_filesampledata_struct::size, LIBMTP_mtpdevice_struct::usbinfo, and LIBMTP_filesampledata_struct::width.

int LIBMTP_Set_File_Name ( LIBMTP_mtpdevice_t *device, LIBMTP_file_t *file, const char *newname)

This function renames a single file. This simply means that the PTP_OPC_ObjectFileName property is updated, if this is supported by the device.
Parameters:
device a pointer to the device that contains the file.
 
file the file metadata of the file to rename. On success, the filename member is updated. Be aware, that this name can be different than newname depending of device restrictions.
 
newname the new filename for this object.
Returns:
0 on success, any other value means failure.
References LIBMTP_file_struct::filename, LIBMTP_file_struct::filetype, and LIBMTP_file_struct::item_id.

Author

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