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

8

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

8

RawDir

typedef struct RawDir RawDir

Description

Provides access to the rawfile directory.

Since

8

RawFile

typedef struct RawFile RawFile

Description

Provides access to the files in rawfile.

Since

8

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

8

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

8

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

8

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

8

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

8

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

8

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

8

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

8

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

8

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

8

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

8

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

8

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

8

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

8

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