EnigmA Amiga Run 1997 February

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TABLE OF CONTENTS Directory Opus 5 External Module Definition 1. Introduction 2. Main module entry point 3. Second module entry point 4. Module identification 5. Function definitions 6. Standard startup code 7. Module callback function 1. Directory Opus 5 supports two types of "external modules". This document describes the main type, an AmigaDos library file. The other type, ARexx modules, are described in the main Opus 5 documentation. Library-based modules are located in the DOpus5:Modules/ directory, and are identified by the ".module" suffix. They are standard AmigaDos libraries, with two compulsory entry points. They main contain any other entry points you want, but the first two are required to work with Opus. The example code supplied with the SDK illustrates how to create an Opus module. While the supplied code is designed for SAS/C, it would be easy to adapt it to any other C compiler. 2. The main entry point to the module is a function called Module_Entry(). The prototype for this function is as follows: long Module_Entry( register __a0 char *args, register __a1 struct Screen *screen, register __a2 IPCData *ipc, register __a3 IPCData *mainipc, register __d0 ULONG mod_id, register __d1 EXT_FUNC(callback) ); This function must be at offset -0x1e in the library, and take parameters in the specified registers. You should never call this function yourself; it is called by Opus when the user runs one of the commands in your module. The parameters to the Module_Entry() function are as follows: args - null-terminated argument string, contains any arguments the user supplied for the command screen - main Opus screen pointer, you should open any requesters on this screen ipc - a pointer to your IPCData structure - Opus launches each module command as a new process mainipc - a pointer to the main IPCData structure for Opus mod_id - the ID code of the command selected by the user callback - address of Opus callback function (see below) 3. The second entry point is a function that the module uses to identify itself. When Opus starts up it scans the contents of the modules directory, and calls this function in each of the modules. The standard modinit.o module startup code supplies this function for you. It is not recommended that you change it. If you need to supply your own function, the prototype is as follows : APTR Module_Identify( register __d0 long num ); This function must be at offset -0x24 in the library. "num" is the command ID number that Opus is enquiring about. If "num" is equal to -1, you must return a pointer to the ModuleInfo structure for the module. If "num" is equal to a valid command ID code, you must return a pointer to a description string for that command. If "num" is an invalid value, you must return 0. 4. The contents of the module are identified with a ModuleInfo structure. All fields of the ModuleInfo structure must be initialised. The meaning of the fields is as follows: ver - Module version number (for your own use) name - pointer to module name, including ".module" suffix locale_name - name of locale catalog for the module. This is opened automatically by the standard modinit.o startup code, which you should use. flags - Module flags, see below function_count - The number of functions in this module function - The definition of the first function Module flag values (for the "flags" field) are as follows: MODULEF_CALL_STARTUP - If this flag is specified, Opus will run your module automatically on startup, with the special "mod_id" value of FUNCID_STARTUP MODULEF_STARTUP_SYNC - If MODULEF_CALL_STARTUP is also specified, this flag causes Opus to wait for your module to return from the startup call before continuing The ModuleInfo structure contains room for only one function definition. If your module contains more than one function, the additional ModuleFunction structures MUST follow the ModuleInfo structure in memory. You must provide as many ModuleFunction structures are were specified in the "function_count" field of the ModuleInfo structure. For example, // Module definition, includes first function ModuleInfo module_info={ 1, // Version "example.module", // Module name "example.catalog", // Catalog name 0, // Flags 2, // Number of functions {0,"Example1",MSG_EXAMPLE1_DESC,0,0}}; // Second function definition follows immediately on ModuleFunction module_func_2={ 1,"Example2",MSG_EXAMPLE2_DESC,0,0}; 5. The ModuleFunction structure is used to define each command that the module provides. The first function is defined with a ModuleFunction structure embedded in the ModuleInfo; additional commands must be defined after that. All fields of the ModuleFunction structure must be initialised, as follows: id - command ID code. This value is passed as the "mod_id" parameter to the Module_Entry() function name - name of the function. This is the actual command name that will be used to invoke this command desc - locale string ID for the function description. This is the ID of the string in the catalog for this module that is used to describe this command in the popup command list. flags - command flags, see below template - command template (in ReadArgs() format). This string is displayed in the popup argument list in Opus function editors, but is not actually parsed by Opus. You will need to use the ParseArgs() routine on the "args" parameter in the Module_Entry() function. ModuleFunction flags are as follows: FUNCF_NEED_SOURCE - set if your module requires a valid source directory - if one is not available, your command will not be launched FUNCF_NEED_DEST - set if your module requires a valid destination directory FUNCF_NEED_FILES - set if you need there to be selected files FUNCF_NEED_DIRS - set if you need selected directories FUNCF_CAN_DO_ICONS - set if you can operate on icons as well as normal files/directories FUNCF_SINGLE_SOURCE - set if you can only operate on a single source lister FUNCF_SINGLE_DEST - set if you can only operate on a single destination lister FUNCF_WANT_DEST - set if you want a destination directory, but don't require one FUNCF_WANT_SOURCE - set if you want a source directory, but don't require one FUNCF_WANT_ENTRIES - set in conjunction with FUNCF_NEED_FILES or FUNCF_NEED_DIRS, to specify that you want those items but don't require them FUNCF_PRIVATE - the function is private, it won't show up in the popup command list 6. It is highly recommended that you link with the standard module startup code (modinit.o) when creating modules. This code contains the Module_Identify() function, and automatically initialises several library bases which you may need. See the <dopus/modules.h> file for more information on this file. 7. The "callback" parameter to the Module_Entry() function provides the address of a callback function within Opus. This function allows you to access information that your module command may need. The callback function is defined as follows: ULONG callback( register __d0 ULONG command, register __a0 APTR handle, register __a1 APTR packet ); command - the callback command, see below for the list handle - the callback handle. You must pass the value of IPCDATA(ipc) for this parameter ("ipc" is the argument passed to the Module_Entry() function) packet - a command-specific packet Following is the list of callback commands. Each command takes a packet specific to it. Command : EXTCMD_GET_SOURCE Purpose : Returns the current source path Packet : char path[256] Returns : struct path_node *path Notes : The packet is a pointer to a 256 character buffer, into which the current source path will be copied. The return value is a pointer to a path_node structure, which can be used with other callback commands. This structure is READ ONLY! Command : EXTCMD_END_SOURCE Purpose : Finishes and cleans up current source path Packet : Set to 0 Returns : <none> Notes : Call this command if you are aborting early and do not wish to process further source paths. Command : EXTCMD_NEXT_SOURCE Purpose : Gets the next source path Packet : char path[256] Returns : struct path_node *path Notes : Call this command when you have finished with the first source path and want to move onto the next one. The return value is NULL if there are no more source paths. Command : EXTCMD_UNLOCK_SOURCE Purpose : Unlock source listers Packet : <none> Returns : <none> Notes : When your module command is called, any source listers are locked automatically. Call this command when you want to unlock them (they are unlocked automatically when your module returns). Command : EXTCMD_GET_DEST Purpose : Returns the next destination path Packet : char path[256] Returns : struct path_node *path Notes : The packet is a pointer to a 256 character buffer, into which the current destination path will be copied. The return value is a handle to the path, which can be used with other callback commands. Call this command repeatedly to move through the destination paths. When all the destination paths have been used, this command will return NULL. If you call this command again, it will will start again with the first destination path. Command : EXTCMD_END_DEST Purpose : Ends the current destination path Packet : FALSE to abort, TRUE to continue Returns : <none> Notes : You must call this command when you have finished with one destination path, prior to calling EXTCMD_GET_DEST. Command : EXTCMD_GET_ENTRY Purpose : Get the next entry to work with Packet : <none> Returns : struct function_entry { struct MinNode node; // Node char *name; // File name APTR entry; // Not used short type; // Type; <0 = file, >0 = dir short flags; // Not used }; Notes : This returns a pointer to the next entry in the current source path. This structure is READ ONLY! Use the "name" field to get the entry name. Command : EXTCMD_END_ENTRY Purpose : Finish with specific entry Packet : struct endentry_packet { struct function_entry *entry; // Entry to end BOOL deselect; // TRUE for deselect }; Returns : <none> Notes : Call this command when you have finished working with one entry and wish to move on to the next. "entry" must be set to the pointer that was returned by EXTCMD_GET_ENTRY. Set "deselect" to TRUE to have the entry deselected in the lister. Command : EXTCMD_RELOAD_ENTRY Purpose : Marks an entry to be reloaded Packet : struct function_entry *entry; Returns : <none> Notes : This command marks the specified entry to be reloaded. When the function finishes, the entry will be reloaded to update any changes that your module might have made to it. Command : EXTCMD_REMOVE_ENTRY Purpose : Marks an entry to be reloaded Packet : struct function_entry *entry; Returns : <none> Notes : This command marks the specified entry to be removed. When the function finishes, the entry will be removed from the lister it is in. Command : EXTCMD_ENTRY_COUNT Purpose : Returns total count of entries Packet : <none> Returns : long entry_count; Notes : Returns the number of selected entries for the function. Command : EXTCMD_ADD_FILE Purpose : Adds a file to a lister Packet : struct addfile_packet { char *path; // Path to add file to struct FileInfoBlock *fib; // FileInfoBlock to add APTR lister; // Lister pointer }; Returns : <none> Notes : Allows you to add a file or directory to a lister. The path field points to the full path of the file to add. fib is an initialised FileInfoBlock which is used to create the file entry. The lister pointer is found in the path_node structure, which is obtained via a call to EXTCMD_GET_SOURCE or EXTCMD_GET_DEST. The display is not updated until you call EXTCMD_DO_CHANGES, or your function returns. Command : EXTCMD_DEL_FILE Purpose : Delete a file from a lister Packet : struct delfile_packet { char *path; // Path file is in char *name; // Filename to delete APTR lister; // Lister pointer }; Returns : <none> Notes : This removes the specified file from any listers it is current shown in. The file itself is not deleted, only the display of it in the lister. The display is not updated until you call EXTCMD_DO_CHANGES, or your function returns. Command : EXTCMD_LOAD_FILE Purpose : Load a new file in a lister Packet : struct loadfile_packet { char *path; // Path file is in char *name; // Name of file short flags; // Flags short reload; // Reload existing file }; Returns : <none> Notes : This command is similar to EXTCMD_ADD_FILE except that it Examines() the file and supplies the FileInfoBlock automatically. 'path' is the full path of the file and 'name' is the file name. The only valid flag at this time is LFF_ICON, which indicates that the icon (.info) of the supplied file is to be loaded instead of the file itself. If 'reload' is set to TRUE, an existing file will be reloaded (ie the old entry in the lister will be removed). Command : EXTCMD_DO_CHANGES Purpose : Perform file changes in listers Packet : <none> Returns : <none> Notes : This command causes any changes made to listers by the EXTCMD_ADD_FILE, EXTCMD_DEL_FILE and EXTCMD_LOAD_FILE commands to be displayed. If your function returns without calling this command, the changes are displayed automatically. Command : EXTCMD_CHECK_ABORT Purpose : Check abort status in lister Packet : <undefined> Returns : BOOL Notes : This command returns TRUE if your 'function' has been aborted by the user. This could have occurred because the user pressed escape or clicked the close button on a lister, or quit the program. Command : EXTCMD_GET_WINDOW Purpose : Get a lister's window pointer Packet : struct path_node *path Returns : struct Window *window Notes : Returns a pointer to the Window for the lister specified by the path_node structure. This is useful if you want to open a requester over a lister window. Command : EXTCMD_GET_HELP Purpose : Get help on a topic Packet : char *topic Returns : <none> Notes : This command causes Opus to open the AmigaGuide help file and search for the named topic. Command : EXTCMD_GET_PORT Purpose : Get ARexx port name Packet : char name[40] Returns : <none> Notes : This command copies the name of the Opus ARexx port into the supplied buffer. Command : EXTCMD_GET_SCREEN Purpose : Get public screen name Packet : char name[40] Returns : <none> Notes : This command copies the name of the Opus public screen into the supplied buffer. Command : EXTCMD_REPLACE_REQ Purpose : Shows a "file exists - replace?" requester Packet : struct replacereq_packet { struct Window *window; // Window to open over struct Screen *screen; // Screen to open on IPCData *ipc; // Process IPC pointer struct FileInfoBlock *file1; // First file information struct FileInfoBlock *file2; // Second file information short flags; // Set to 0 for now }; Returns : Result of requester; REPLACE_ABORT for abort, REPLACE_LEAVE for skip or REPLACE_REPLACE for replace. If the REPLACEF_ALL flag is set, it indicates an "All" gadget (eg Skip All, Replace All) Command : EXTCMD_GET_SCREENDATA Purpose : Get information about the Opus display Packet : <none> Returns : struct DOpusScreenData { struct Screen *screen; // Pointer to Opus screen struct DrawInfo *draw_info; // DrawInfo structure USHORT depth; // Depth of screen USHORT pen_alloc; // Pen allocation flag USHORT pen_array[16]; // User pen array USHORT pen_count; // Number of pens; }; Notes : Returns a structure with useful information about the Opus screen. This structure is READ ONLY! Call EXTCMD_FREE_SCREENDATA to free it. Command : EXTCMD_FREE_SCREENDATA Purpose : Free a DOpusScreenData structure Packet : struct DOpusScreenData * Returns : <none> Notes : Frees the result of an EXTCMD_GET_SCREENDATA call ` Command : EXTCMD_SEND_COMMAND Purpose : Send an ARexx command to DOpus Packet : struct command_packet { char *command; // Command to send ULONG flags; // Command flags char *result; // Result pointer ULONG rc; // Result code }; Returns : TRUE if the message was sent Notes : This command allows you to send an ARexx instruction directly to the Opus ARexx port. Set the COMMANDF_RESULT flag if you want a result string returned; if one is, the 'result' field of the packet will contain a pointer to it. You MUST call FreeVec() on this pointer when you have finished with the result.