Path: utzoo!mnetor!uunet!nuchat!peter
From: peter@nuchat.UUCP (Peter da Silva)
Newsgroups: comp.sys.amiga
Subject: IPC -- as the concept gels.
Message-ID: <783@nuchat.UUCP>
Date: 13 Mar 88 03:59:13 GMT
Organization: Public Access - Houston, Tx
Lines: 94

Well, there have been some good ideas out there...

Still using the Browser as the technology demonstrator...

struct IPCEntry {
	ULONG IE_Id;			/* name of this entry */
	void *IE_Ptr;			/* this entry's data */
};
struct IPCMessage {
	struct Message IPC_Message;	/* ln_Name == tool name */
	ULONG IPC_Status;		/* Return status */
	ULONG IPC_Type;			/* Identify this message type */
	ULONG IPC_Entries;		/* Number of IPC entries */
	struct IPCEntry IPC_Data[];	/* Entries */
};

struct IPCPort should probably be the reference-counted port that Matt
Dillon described. It's a LOT safer than the current ports, and a LOT cleaner
than the various message-broker setups floating around.

All messages are replied to using ReplyMsg(). Any pointers in the structure
rendered invalid by the program should be zeroed out before replying. This
means Freed memory or locks, or even just stuff that you intend to keep
around and delete later. The program that sent the original message should
keep this in mind when cleaning up.

Specific browser info:

	Name = BRWS;

Entries defined by this Server:

	Id = FILE
	Ptr =	struct IE_File {
			ULONG DirLock;
			char *FileName;
		};

	Id = PORT
	Ptr = struct MsgPort *;

	Id = WNDW
	Ptr = struct Window *;

	Id = CSTR
	Ptr = char *; /* points to a 'C' type string */

Messages defined by this Server:

	Type = ADDF, 1 Entry: FILE;
		Browser check to see if it's got that
		particular directory locked, and if so
		it goes ahead and adds that file to its
		window;
	Type = DELF, 1 Entry: FILE;
		Like ADDF, but deletes that file from
		the window;
	Type = ADDT, 2 Entries: CSTR, PORT;
		Adds entry to Tools menu. Name is taken
		from CSTR. When that entry is selected
		Browser will send an IPCMessage containing
		the files selected in FILE format.
	Type = DELT, 1 Entry: PORT;
		Deletes all entries from Tools menu using
		that PORT.
	Type = DELT, 2 Entries: CSTR, PORT;
		Deletes the entry from the Tools menu that
		matches that string and port.
	Type = ADDW, 2 Entries: WNDW, PORT;
		Adds that window to its "copy" list. When the
		user drops files in that window they will be
		sent to the program in an IPCMessage containing
		the files selected in FILE format.
	Type = DELW, 1 Entry: PORT;
		Deletes all windows from the "copy" list using
		that PORT.
	Type = DELW, 2 Entries: WNDW, PORT;
		Deletes the entry from the "copy" list that
		matches that window and port.

I guess the FILE entries could be handled as paired LOCK and
CSTR entries, but it's used often enough that it's worthwhile
doing it here.

Note the DELW and DELT entries have two forms available. This
is a side-effect of the format.

Browser will not keep any of the FILE entries passed in ADDF or DELF.
It will zero out the CSTR, WNDW, and PORT entries in ADDT and ADDW, but
not in DELT or DELW.
-- 
-- a clone of Peter (have you hugged your wolf today) da Silva  `-_-'
-- normally  ...!hoptoad!academ!uhnix1!sugar!peter                U
-- Disclaimer: These aren't mere opinions... these are *values*.