MTK platform learning-Analysis of the FileManager Module

FileManager module Analysis

1. External Interface

1. Functions of the interface functions used by other modules
Mmi_fmgr_init initialize file manager context
Mmi_fmgr_select_path_and_entry entry point to file manager for other applications
Mmi_fmgr_reset_app_select reset selection from other application
GetFileSystemErrorString convert file system return error code to error messgae pop up

2. Analyze mmi_fmgr_select_path_and_entry, mmi_fmgr_reset_app_selec
Function prototype: void mmi_fmgr_select_path_and_entry (U8 app_id, U8 sel_type, U32 filter, PS8 start_path, PsFuncPtr callback );
(1) mainly analyze the callback function
A. excute mmi_fmgr_select_path_and_entry (......)
Start_path
---> Callback (.....)
---> Callback internal check: N
Start_path = NULL? ---> The selection is completed
|
| Y
The selection is aborted
B. Influence of FMGR_SELECT_REPEAT on callback function and
You can use fmgr_select_repeat to select files/folders multiple times.
A. Each select
Select target
Start_path
---> Callback (......)
---> Callback Internal Check n
Start_path = NULL? ---> User abort (the selection is aborted)
|
| Y
Reach application's condition? ---> Application abort (the selection is aborted)
|
|
The selection is completed
B. Two types of abort
User ABORT:
Will cause a callback with null parameter and file manager will automatically reset;
Application abort:
Needs to call the mmi_fmgr_reset_app_select () to terminate the process
(2) FMGR_SELECT_BROWSE Parameter
Drive option
Folder option
File option

3. Utility Functions
BOOL mmi_fmgr_get_default_folder_path (S8 * folder, S8 * path, 2010length );
Void mmi_fmgr_remove_last_dir (S8 * path );
S8 * mmi_fmgr_extract_file_name (S8 * path );
S8 * mmi_fmgr_extract_ext_file_name (S8 * path );
Void mmi_fmgr_hide_ext_name (S8 * path );
Mmi_fmgr_check_file_present


Ii. Cache

1. First Time Enter a Floder
A. General Process
First time enter a floder
--> Call fmgr_kenmel: init the cache
--> Load file frome FS until the cache is filled
--> Whether or not the sort option is available, file manager obtains the file list.
B. About sort API
When the number of files in a directory item exceeds 255, file manager can't use sort API to get file list from file system
But linear find first/find next instead.
C. filter

2. Request for File Info
A. Function: fmgr_kernel_get_file_info
B. call fmgr_kernel_get_file_info with a index
--> Get A structe of Data filled with useful File Information
--> This funciton will use the passed in index to see y
If the desired file info is already in chached or not ---> from Cache
|
| N
|
Reload cache and return file info

3. Image Cache
A. Preview image Cache of the File Manger Module
B. General Process
Draw Thumb Image
Y
--> Is in cache? -----> Draw it from cache
|
| N
|
Decord image -----> decord done -----> cache the image -----> draw it from Cache