harmony 鸿蒙Rawfile

2023-06-24
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Rawfile

Provides APIs for operating the rawfile directory and its files, including traversing the rawfile directory and opening, searching for, reading, and closing a file in it.

Since

Summary

Files

Name	Description
raw_dir.h	Provides functions related to the rawfile directory. File to include: <rawfile/raw_dir.h> Library: librawfile.z.so
raw_file.h	Provides functions related to the files in the rawfile directory. File to include: <rawfile/raw_file.h> Library: librawfile.z.so
raw_file_manager.h	Provides file management functions for the rawfile directory. File to include: <rawfile/raw_file_manager.h> Library: librawfile.z.so

Structs

Name	Description
RawFileDescriptor	Defines the file descriptor (FD) information of a file in the rawfile directory.

Types

Name	Description
RawDir	Provides access to the rawfile directory.
RawFile	Provides access to the files in rawfile.
NativeResourceManager	Represents the resource manager.

Functions

Name	Description
OH_ResourceManager_GetRawFileName (RawDir *rawDir, int index)	Obtains the name of a file in rawfile based on the index.
OH_ResourceManager_GetRawFileCount (RawDir *rawDir)	Obtains the number of files in a RawDir.
OH_ResourceManager_CloseRawDir (RawDir *rawDir)	Closes a RawDir and releases all associated resources.
OH_ResourceManager_ReadRawFile (const RawFile rawFile, void buf, size_t length)	Reads data from a file in rawfile.
OH_ResourceManager_SeekRawFile (const RawFile *rawFile, long offset, int whence)	Seeks for the data read/write position in a file in rawfile based on the specified offset.
OH_ResourceManager_GetRawFileSize (RawFile *rawFile)	Obtains the size of a file in rawfile.
OH_ResourceManager_CloseRawFile (RawFile *rawFile)	Closes a RawFile and releases all associated resources.
OH_ResourceManager_GetRawFileOffset (const RawFile *rawFile)	Obtains the current offset of a file in rawfile.
OH_ResourceManager_GetRawFileDescriptor (const RawFile *rawFile, RawFileDescriptor &descriptor)	Opens a file in rawfile based on the offset and file length and obtains the FD.
OH_ResourceManager_ReleaseRawFileDescriptor (const RawFileDescriptor &descriptor)	Releases an FD.
OH_ResourceManager_InitNativeResourceManager (napi_env env, napi_value jsResMgr)	Initializes a Native resource manager using the JavaScript resource manager. You can use the Native resource manager obtained to implement operations related to rawfile.
OH_ResourceManager_ReleaseNativeResourceManager (NativeResourceManager *resMgr)	Releases a Native resource manager instance.
OH_ResourceManager_OpenRawDir (const NativeResourceManager mgr, const char dirName)	Opens a directory in the rawfile directory.
OH_ResourceManager_OpenRawFile (const NativeResourceManager mgr, const char fileName)	Opens a file in the rawfile directory.

Description

Type Description

NativeResourceManager

typedef struct NativeResourceManager NativeResourceManager

Description

Represents the resource manager.

This class encapsulates the native implementation of the JavaScript resource manager. The ResourceManager pointer can be obtained by using OH_ResourceManager_InitNativeResourceManager.

Since

RawDir

typedef struct RawDir RawDir

Description

Provides access to the rawfile directory.

Since

RawFile

typedef struct RawFile RawFile

Description

Provides access to the files in rawfile.

Since

Function Description

OH_ResourceManager_CloseRawDir()

void OH_ResourceManager_CloseRawDir (RawDir * rawDir)

Description

Closes a RawDir opened and releases all associated resources.

Parameters

Name	Description
rawDir	Pointer to the RawDir to close.

See

OH_ResourceManager_OpenRawDir

Since

OH_ResourceManager_CloseRawFile()

void OH_ResourceManager_CloseRawFile (RawFile * rawFile)

Description

Closes a RawFile and releases all associated resources.

Parameters

Name	Description
rawFile	Pointer to the RawFile to close.

See

OH_ResourceManager_OpenRawFile

Since

OH_ResourceManager_GetRawFileCount()

int OH_ResourceManager_GetRawFileCount (RawDir * rawDir)

Description

Obtains the number of files in a RawDir.

You can use this function to obtain available indexes in OH_ResourceManager_GetRawFileName.

Parameters

Name	Description
rawDir	Pointer to the target RawDir.

See

OH_ResourceManager_GetRawFileName

Since

OH_ResourceManager_GetRawFileDescriptor()

bool OH_ResourceManager_GetRawFileDescriptor (const RawFile * rawFile, RawFileDescriptor & descriptor )

Description

Opens a file in the rawfile directory based on the offset and file length and obtains the FD.

The FD obtained can be used to read the file.

Parameters

Name	Description
rawFile	Pointer to the RawFile.
descriptor	File descriptor of the file, start position of the file in the hAP, and length of the file.

Returns

Returns true if the file is opened; returns false if the access to the file is rejected.

Since

OH_ResourceManager_GetRawFileName()

const char* OH_ResourceManager_GetRawFileName (RawDir * rawDir, int index )

Description

Obtains the name of a file in rawfile based on the index.

You can use this function to traverse the rawfile directory.

Parameters

Name	Description
rawDir	Pointer to the RawDir.
index	Index of the file in the RawDir.

Returns

Returns the file name obtained if the file exists in the directory; returns null otherwise. The file name returned can be used as the input parameter of OH_ResourceManager_OpenRawFile.

See

OH_ResourceManager_OpenRawFile

Since

OH_ResourceManager_GetRawFileOffset()

long OH_ResourceManager_GetRawFileOffset (const RawFile * rawFile)

Description

Obtains the current offset of a file in rawfile.

The offset indicates the position of the file in the HAP.

Parameters

Name	Description
rawFile	Pointer to the target RawFile.

Returns

Returns the file offset obtained.

Since

OH_ResourceManager_GetRawFileSize()

long OH_ResourceManager_GetRawFileSize (RawFile * rawFile)

Description

Obtains the size of a file in rawfile.

Parameters

Name	Description
rawFile	Pointer to the target RawFile.

Returns

Returns the file size obtained.

Since

OH_ResourceManager_InitNativeResourceManager()

NativeResourceManager* OH_ResourceManager_InitNativeResourceManager (napi_env env, napi_value jsResMgr )

Description

Initializes a Native resource manager using the JavaScript resource manager.

You can use the resource manager obtained to implement rawfile operations.

Parameters

Name	Description
env	Pointer to the JavaScript Native API (napi) environment.
jsResMgr	JavaScript resource manager.

Returns

Returns the pointer to the NativeResourceManager obtained.

Since

OH_ResourceManager_OpenRawDir()

RawDir* OH_ResourceManager_OpenRawDir (const NativeResourceManager * mgr, const char * dirName )

Description

Opens a directory in rawfile.

After opening the directory, you can traverse all files in it.

Parameters

Name	Description
mgr	Pointer to the NativeResourceManager, which is obtained by using OH_ResourceManager_InitNativeResourceManager.
dirName	Pointer to the name of the directory to open. If this field is left empty, the root directory will be opened.

Returns

Returns the pointer to the RawDir opened. You can use OH_ResourceManager_CloseRawDir to close the directory and release resources.

See

OH_ResourceManager_InitNativeResourceManager

OH_ResourceManager_CloseRawDir

Since

OH_ResourceManager_OpenRawFile()

RawFile* OH_ResourceManager_OpenRawFile (const NativeResourceManager * mgr, const char * fileName )

Description

Opens a file in rawfile.

After the file is opened, you can read data in it.

Parameters

Name	Description
mgr	Pointer to the NativeResourceManager, which is obtained by using OH_ResourceManager_InitNativeResourceManager.
fileName	Pointer to the name of the file in the relative path of the rawfile root directory.

Returns

Returns the pointer to the RawFile opened. You can use OH_ResourceManager_CloseRawFile to close the file and release resources.

See

OH_ResourceManager_InitNativeResourceManager

OH_ResourceManager_CloseRawFile

Since

OH_ResourceManager_ReadRawFile()

int OH_ResourceManager_ReadRawFile (const RawFile * rawFile, void * buf, size_t length )

Description

Reads a file in rawfile.

You can use this function to read data of the specified length from the current position.

Parameters

Name	Description
rawFile	Pointer to the RawFile to read.
buf	Pointer to the buffer for receiving the read data.
length	Length of the data to read.

Returns

Returns the number of bytes read. If the read length is less than the file length, 0 is returned.

Since

OH_ResourceManager_ReleaseNativeResourceManager()

void OH_ResourceManager_ReleaseNativeResourceManager (NativeResourceManager * resMgr)

Description

Releases a Native resource manager instance.

Parameters

Name	Description
resMgr	Pointer to the NativeResourceManager instance to release.

Since

OH_ResourceManager_ReleaseRawFileDescriptor()

bool OH_ResourceManager_ReleaseRawFileDescriptor (const RawFileDescriptor & descriptor)

Description

Releases the FD of a file in rawfile.

To prevent FD leakage, you are advised to release an FD immediately after use.

Parameters

Name	Description
descriptor	File descriptor to close. It contains the FD, start position in the HAP, and file length.

Returns

Returns true if the FD is released; returns false otherwise.

Since

OH_ResourceManager_SeekRawFile()

int OH_ResourceManager_SeekRawFile (const RawFile * rawFile, long offset, int whence )

Description

Seeks for the data read/write position in a file in rawfile based on the specified offset.

Parameters

Name	Description
rawFile	Pointer to the target RawFile.
offset	Offset.
whence	Read/Write position. The options are as follows: 0: The read/write position is the offset. 1: The read/write position is the current position plus the offset. 2: The read/write position is the end of the file (EOF) plus the offset.

Returns

If the operation is successful, 0 is returned and the rawFile pointer is directed to the new read/write position. If an error occurs, (long) -1 is returned.

Since