unit uFLIPC;

interface

uses SDLh, uFLTypes;

var msgFrontend, msgEngine: TIPCMessage;

    mutFrontend, mutEngine: PSDL_mutex;

    condFrontend, condEngine: PSDL_cond;

procedure initIPC;

procedure freeIPC;

procedure ipcToEngine(s: shortstring);

procedure ipcToEngineRaw(p: pointer; len: Longword);

//function  ipcReadFromEngine: shortstring;

//function  ipcCheckFromEngine: boolean;

procedure ipcToFrontend(s: shortstring);

procedure ipcToFrontendRaw(p: pointer; len: Longword);

function ipcReadFromFrontend: shortstring;

function ipcCheckFromFrontend: boolean;

procedure registerIPCCallback(p: pointer; f: TIPCCallback);

implementation

var callbackPointer: pointer;

    callbackFunction: TIPCCallback;

    callbackListenerThread: PSDL_Thread;

procedure ipcSend(var s: TIPCMessage; var msg: TIPCMessage; mut: PSDL_mutex; cond: PSDL_cond);

begin

    SDL_LockMutex(mut);

    while (msg.str[0] > #0) or (msg.buf <> nil) do

        SDL_CondWait(cond, mut);

    msg:= s;

    SDL_CondSignal(cond);

    SDL_UnlockMutex(mut);

end;

function ipcRead(var msg: TIPCMessage; mut: PSDL_mutex; cond: PSDL_cond): TIPCMessage;

var tmp: pointer;

begin

    SDL_LockMutex(mut);

    while (msg.str[0] = #0) and (msg.buf = nil) do

        SDL_CondWait(cond, mut);

    if msg.buf <> nil then

    begin

        tmp:= msg.buf;

        msg.buf:= GetMem(msg.len);

        Move(tmp^, msg.buf^, msg.len);

        FreeMem(tmp, msg.len)

    end;

    ipcRead:= msg;

    msg.str[0]:= #0;

    msg.buf:= nil;

    SDL_CondSignal(cond);

    SDL_UnlockMutex(mut)

end;

function ipcCheck(var msg: TIPCMessage; mut: PSDL_mutex): boolean;

begin

    SDL_LockMutex(mut);

    ipcCheck:= (msg.str[0] > #0) or (msg.buf <> nil);

    SDL_UnlockMutex(mut)

end;

procedure ipcToEngine(s: shortstring);

var msg: TIPCMessage;

begin

    msg.str:= s;

    msg.buf:= nil;

    ipcSend(msg, msgEngine, mutEngine, condEngine)

end;

procedure ipcToFrontend(s: shortstring);

var msg: TIPCMessage;

begin

    msg.str:= s;

    msg.buf:= nil;

    ipcSend(msg, msgFrontend, mutFrontend, condFrontend)

end;

procedure ipcToEngineRaw(p: pointer; len: Longword);

var msg: TIPCMessage;

begin

    msg.str[0]:= #0;

    msg.len:= len;

    msg.buf:= GetMem(len);

    Move(p^, msg.buf^, len);

    ipcSend(msg, msgEngine, mutEngine, condEngine)

end;

procedure ipcToFrontendRaw(p: pointer; len: Longword);

var msg: TIPCMessage;

begin

    msg.str[0]:= #0;

    msg.len:= len;

    msg.buf:= GetMem(len);

    Move(p^, msg.buf^, len);

    ipcSend(msg, msgFrontend, mutFrontend, condFrontend)

end;

function ipcReadFromEngine: TIPCMessage;

begin

    ipcReadFromEngine:= ipcRead(msgFrontend, mutFrontend, condFrontend)

end;

function ipcReadFromFrontend: shortstring;

begin

    ipcReadFromFrontend:= ipcRead(msgEngine, mutEngine, condEngine).str

end;

function ipcCheckFromEngine: boolean;

begin

    ipcCheckFromEngine:= ipcCheck(msgFrontend, mutFrontend)

end;

function ipcCheckFromFrontend: boolean;

begin

    ipcCheckFromFrontend:= ipcCheck(msgEngine, mutEngine)

end;

var msg: TIPCMessage;

begin

    repeat

        msg:= ipcReadFromEngine();

        if msg.buf = nil then

            callbackFunction(callbackPointer, @msg.str[1], byte(msg.str[0]))

        else

        begin

            callbackFunction(callbackPointer, msg.buf, msg.len);

            FreeMem(msg.buf, msg.len)

        end

    until false

end;

procedure registerIPCCallback(p: pointer; f: TIPCCallback);

begin

    callbackPointer:= p;

    callbackFunction:= f;

end;

procedure initIPC;

begin

    msgFrontend.str:= '';

    msgFrontend.buf:= nil;

    msgEngine.str:= '';

    msgEngine.buf:= nil;

    callbackPointer:= nil;

    callbackListenerThread:= nil;

    mutFrontend:= SDL_CreateMutex;

    mutEngine:= SDL_CreateMutex;

    condFrontend:= SDL_CreateCond;

    condEngine:= SDL_CreateCond;

end;

procedure freeIPC;

begin

    SDL_KillThread(callbackListenerThread);

    SDL_DestroyMutex(mutFrontend);

    SDL_DestroyMutex(mutEngine);

    SDL_DestroyCond(condFrontend);

    SDL_DestroyCond(condEngine);

end;

end.