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/* ScummVM - Graphic Adventure Engine
*
* ScummVM is the legal property of its developers, whose names
* are too numerous to list here. Please refer to the COPYRIGHT
* file distributed with this source distribution.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
*/
#ifndef COMMON_COROUTINES_H
#define COMMON_COROUTINES_H
#include "common/scummsys.h"
#include "common/util.h" // for SCUMMVM_CURRENT_FUNCTION
#include "common/list.h"
#include "common/singleton.h"
namespace Common {
/**
* @defgroup common_coroutine Coroutine support for simulating multi-threading
* @ingroup common
*
* @brief The following implementation is loosely based on an article by Simon Tatham:
* @linkCoroutine.
* However, many improvements and tweaks have been made, in particular
* by taking advantage of C++ features not available in C.
*
* @{
*/
#define CoroScheduler (Common::CoroutineScheduler::instance())
// Enable this macro to enable some debugging support in the coroutine code.
//#define COROUTINE_DEBUG
/**
* The core of any coroutine context which captures the 'state' of a coroutine.
* Private use only.
*/
struct CoroBaseContext {
int _line;
int _sleep;
CoroBaseContext *_subctx;
#ifdef COROUTINE_DEBUG
const char *_funcName;
#endif
/**
* Create a coroutine context.
*/
CoroBaseContext(const char *func);
/**
* Destructor for coroutine context.
*/
virtual ~CoroBaseContext();
};
typedef CoroBaseContext *CoroContext;
/** This is a special constant that can be temporarily used as a parameter to call coroutine-ised
* methods from code that have not yet been converted to being a coroutine, so code at least
* compiles correctly. Be aware, though, that an error will occur if a coroutine that was passed
* the nullContext tries to sleep or yield control.
*/
extern CoroContext nullContext;
/**
* Wrapper class which holds a pointer to a pointer to a CoroBaseContext.
* Note that the destructor kills the context being held,
* but ONLY if the _sleep val of that context is zero. This way, a coroutine
* can just 'return' without freeing the allocated context
* (in Simon Tatham's original code, one had to use a special macro to
* return from a coroutine).
*/
class CoroContextHolder {
CoroContext &_ctx;
public:
CoroContextHolder(CoroContext &ctx) : _ctx(ctx) {
assert(ctx);
assert(ctx->_sleep >= 0);
ctx->_sleep = 0;
}
~CoroContextHolder() {
if (_ctx && _ctx->_sleep == 0) {
delete _ctx;
_ctx = nullptr;
}
}
};
/** Set this as the first parameter for methods that have been converted to being a coroutine. */
#define CORO_PARAM Common::CoroContext &coroParam
/**
* Begin the declaration of a coroutine context.
* This allows declaring variables which are 'persistent' during the
* lifetime of the coroutine. Example usage:
* @code
* CORO_BEGIN_CONTEXT;
* int var;
* char *foo;
* CORO_END_CONTEXT(_ctx);
* @endcode
* It is not possible to initialize variables here, due to the way this
* macro is implemented. Furthermore, to use the variables declared in
* the coroutine context, you must access them through the context variable
* name that was specified as a parameter to @c CORO_END_CONTEXT, e.g.
* _ctx->var = 0;
*
* @see CORO_END_CONTEXT
*
* @note A 'DUMMY' variable is declared to allow the user to specify an 'empty'
* context, and so that compilers do not complain about ";" following the macro.
*/
#define CORO_BEGIN_CONTEXT \
struct CoroContextTag : Common::CoroBaseContext { \
CoroContextTag() : CoroBaseContext(SCUMMVM_CURRENT_FUNCTION) { DUMMY = 0; } \
int DUMMY
/**
* End the declaration of a coroutine context.
* @param x Name of the coroutine context.
* @see CORO_BEGIN_CONTEXT
*/
#define CORO_END_CONTEXT(x) } *x = (CoroContextTag *)coroParam
/**
* Begin the code section of a coroutine.
* @param x Name of the coroutine context.
*/
#define CORO_BEGIN_CODE(x) \
if (&coroParam == &Common::nullContext) assert(!Common::nullContext); \
if (!x) { coroParam = x = new CoroContextTag(); } \
x->DUMMY = 0; \
Common::CoroContextHolder tmpHolder(coroParam); \
switch (coroParam->_line) { default: break; case 0:;
/**
* End the code section of a coroutine.
*/
#define CORO_END_CODE \
if (&coroParam == &Common::nullContext) { \
delete Common::nullContext; \
Common::nullContext = NULL; \
} \
}
/**
* Sleep for the specified number of scheduler cycles.
*/
#define CORO_SLEEP(delay) \
do { \
coroParam->_line = __LINE__; \
coroParam->_sleep = delay; \
assert(&coroParam != &Common::nullContext); \
return; case __LINE__:; \
} while (0)
#define CORO_GIVE_WAY do { CoroScheduler.giveWay(); CORO_SLEEP(1); } while (0)
#define CORO_RESCHEDULE do { CoroScheduler.reschedule(); CORO_SLEEP(1); } while (0)
/**
* Stop the currently running coroutine and all calling coroutines.
*
* This sets _sleep to -1 rather than 0 so that the context does not get
* deleted by CoroContextHolder, since we want @ref CORO_INVOKE_ARGS to
* propagate the _sleep value and return immediately (the scheduler will
* then delete the entire coroutine's state, including all subcontexts).
*/
#define CORO_KILL_SELF() \
do { if (&coroParam != &Common::nullContext) { coroParam->_sleep = -1; } return; } while (0)
/**
* Use this macro in conjunction with @ref CORO_INVOKE_ARGS and
* similar macros for calling coroutine-enabled subroutines.
*/
#define CORO_SUBCTX coroParam->_subctx
/**
* Invoke another coroutine.
*
* If the subcontext still exists after the coroutine is invoked, it has
* either yielded/slept or killed itself, and so we copy the _sleep value
* to our own context and return (execution will continue at the case
* statement below, where we loop and call the coroutine again).
* If the subcontext is null, the coroutine ended normally, and we can
* simply break out of the loop and continue execution.
*
* @param subCoro Name of the coroutine-enabled function to invoke.
* @param ARGS List of arguments to pass to subCoro.
*
* @note @p ARGS must be surrounded by parentheses, and the first argument
* in this list must always be CORO_SUBCTX. For example, the
* regular function call
* myFunc(a, b);
* becomes the following:
* CORO_INVOKE_ARGS(myFunc, (CORO_SUBCTX, a, b));
*/
#define CORO_INVOKE_ARGS(subCoro, ARGS) \
do { \
coroParam->_line = __LINE__; \
coroParam->_subctx = 0; \
do { \
subCoro ARGS; \
if (!coroParam->_subctx) break; \
coroParam->_sleep = coroParam->_subctx->_sleep; \
assert(&coroParam != &Common::nullContext); \
return; case __LINE__:; \
} while (1); \
} while (0)
/**
* Invoke another coroutine. Similar to @ref CORO_INVOKE_ARGS,
* but allows specifying a return value which is returned
* if the invoked coroutine yields (thus causing the current
* coroutine to yield, too).
*/
#define CORO_INVOKE_ARGS_V(subCoro, RESULT, ARGS) \
do { \
coroParam->_line = __LINE__; \
coroParam->_subctx = 0; \
do { \
subCoro ARGS; \
if (!coroParam->_subctx) break; \
coroParam->_sleep = coroParam->_subctx->_sleep; \
assert(&coroParam != &Common::nullContext); \
return RESULT; case __LINE__:; \
} while (1); \
} while (0)
/**
* Convenience wrapper for @ref CORO_INVOKE_ARGS for invoking a coroutine
* with no parameters.
*/
#define CORO_INVOKE_0(subCoroutine) \
CORO_INVOKE_ARGS(subCoroutine, (CORO_SUBCTX))
/**
* Convenience wrapper for @ref CORO_INVOKE_ARGS for invoking a coroutine
* with one parameter.
*/
#define CORO_INVOKE_1(subCoroutine, a0) \
CORO_INVOKE_ARGS(subCoroutine, (CORO_SUBCTX, a0))
/**
* Convenience wrapper for CORO_INVOKE_ARGS for invoking a coroutine
* with two parameters.
*/
#define CORO_INVOKE_2(subCoroutine, a0,a1) \
CORO_INVOKE_ARGS(subCoroutine, (CORO_SUBCTX, a0, a1))
/**
* Convenience wrapper for @ref CORO_INVOKE_ARGS for invoking a coroutine
* with three parameters.
*/
#define CORO_INVOKE_3(subCoroutine, a0,a1,a2) \
CORO_INVOKE_ARGS(subCoroutine, (CORO_SUBCTX, a0, a1, a2))
/**
* Convenience wrapper for CORO_INVOKE_ARGS for invoking a coroutine
* with four parameters.
*/
#define CORO_INVOKE_4(subCoroutine, a0,a1,a2,a3) \
CORO_INVOKE_ARGS(subCoroutine, (CORO_SUBCTX, a0, a1, a2, a3))
/** Size of process-specific information. */
#define CORO_PARAM_SIZE 40
/** Maximum number of processes. */
#define CORO_NUM_PROCESS 100
#define CORO_MAX_PROCESSES 100
#define CORO_MAX_PID_WAITING 5
#define CORO_INFINITE 0xffffffff
#define CORO_INVALID_PID_VALUE 0
/** Coroutine parameter for methods converted to coroutines. */
typedef void (*CORO_ADDR)(CoroContext &, const void *);
/** process structure */
struct PROCESS {
PROCESS *pNext; ///< Pointer to the next process in an active or free list.
PROCESS *pPrevious; ///< Pointer to the previous process in an active or free list.
CoroContext state; ///< State of the coroutine.
CORO_ADDR coroAddr; ///< Entry point of the coroutine.
int sleepTime; ///< Number of scheduler cycles to sleep.
uint32 pid; ///< Process ID.
uint32 pidWaiting[CORO_MAX_PID_WAITING]; ///< Process ID(s) that the process is currently waiting on.
#ifndef NO_CXX11_ALIGNAS
alignas(max_align_t)
#endif
char param[CORO_PARAM_SIZE]; ///< Process-specific information.
};
typedef PROCESS *PPROCESS;
/** Event structure. */
struct EVENT {
uint32 pid;
bool manualReset;
bool signalled;
bool pulsing;
};
/**
* Create and manage "processes" (really coroutines).
*/
class CoroutineScheduler : public Singleton<CoroutineScheduler> {
public:
/** Pointer to a function of the form "void function(PPROCESS)" */
typedef void (*VFPTRPP)(PROCESS *);
private:
friend class Singleton<CoroutineScheduler>;
/**
* Constructor.
*/
CoroutineScheduler();
/**
* Destructor.
*/
~CoroutineScheduler();
/** List of all processes. */
PROCESS *processList;
/** Active process list. Saves scheduler state. */
PROCESS *active;
/** Pointer to the free process list. */
PROCESS *pFreeProcesses;
/** Currently active process. */
PROCESS *pCurrent;
/** Auto-incrementing process ID. */
int pidCounter;
/** Event list. */
Common::List<EVENT *> _events;
#ifdef DEBUG
/** Diagnostic process counters. */
int numProcs;
int maxProcs;
/**
* Check both the active and free process list to ensure that all links are valid,
* and that no processes have been lost.
*/
void checkStack();
#endif
/**
* Called from killProcess() to enable other resources
* a process may be allocated to be released.
*/
VFPTRPP pRCfunction;
PROCESS *getProcess(uint32 pid);
EVENT *getEvent(uint32 pid);
public:
/**
* Kill all processes and place them on the free list.
*/
void reset();
#ifdef DEBUG
/**
* Show the maximum number of processes used at once.
*/
void printStats();
#endif
/**
* Give all active processes a chance to run.
*/
void schedule();
/**
* Reschedule all processes to run again this tick.
*/
void rescheduleAll();
/**
* If the specified process has already run on this tick, make it run
* again on the current tick.
*/
void reschedule(PPROCESS pReSchedProc = nullptr);
/**
* Move the specified process to the end of the dispatch queue
* allowing it to run again within the current game cycle.
* @param pReSchedProc The process to move.
*/
void giveWay(PPROCESS pReSchedProc = nullptr);
/**
* Continuously make a given process wait for another process to finish or event to signal.
*
* @param pid Process/Event identifier.
* @param duration Duration in milliseconds.
* @param expired If specified, set to true if the delay period expired.
*/
void waitForSingleObject(CORO_PARAM, int pid, uint32 duration, bool *expired = nullptr);
/**
* Continuously make a given process wait for given processes to finish or events to be set.
*
* @param nCount Number of IDs being passed.
* @param pidList List of process IDs to wait for.
* @param bWaitAll Whether to wait for all or any of the processes/events.
* @param duration Duration in milliseconds.
* @param expired Set to true if the delay period expired.
*/
void waitForMultipleObjects(CORO_PARAM, int nCount, uint32 *pidList, bool bWaitAll,
uint32 duration, bool *expired = nullptr);
/**
* Make the active process sleep for the given duration in milliseconds.
*
* @param duration Duration in milliseconds
* @remarks This duration is not precise, since it relies on the frequency the
* scheduler is called.
*/
void sleep(CORO_PARAM, uint32 duration);
/**
* Create a new process.
*
* @param pid Process identifier.
* @param coroAddr Coroutine start address.
* @param pParam Process-specific information.
* @param sizeParam Size of the process-specific information.
*/
PROCESS *createProcess(uint32 pid, CORO_ADDR coroAddr, const void *pParam, int sizeParam);
/**
* Create a new process with an auto-incrementing Process ID.
*
* @param coroAddr Coroutine start address.
* @param pParam Process-specific information.
* @param sizeParam Size of process-specific information.
*/
uint32 createProcess(CORO_ADDR coroAddr, const void *pParam, int sizeParam);
/**
* Create a new process with an auto-incrementing Process ID and a single pointer parameter.
*
* @param coroAddr Coroutine start address.
* @param pParam Process-specific information.
*/
uint32 createProcess(CORO_ADDR coroAddr, const void *pParam);
/**
* Kill the specified process.
*
* @param pKillProc The process to kill.
*/
void killProcess(PROCESS *pKillProc);
/**
* Return a pointer to the currently running process.
*/
PROCESS *getCurrentProcess();
/**
* Return the process identifier of the currently running process.
*/
int getCurrentPID() const;
/**
* Kill any process matching the specified PID. The current
* process cannot be killed.
*
* @param pidKill Process identifier of the process to kill.
* @param pidMask Mask to apply to process identifiers before comparison.
* @return The number of processes killed.
*/
int killMatchingProcess(uint32 pidKill, int pidMask = -1);
/**
* Set pointer to a function to be called by killProcess().
*
* May be called by a resource allocator. The function supplied is
* called by killProcess() to allow the resource allocator to free
* resources allocated to the dying process.
*
* @param pFunc Function to be called by killProcess().
*/
void setResourceCallback(VFPTRPP pFunc);
/** @name Event methods
* @{
*/
/**
* Create a new event (semaphore) object.
*
* @param bManualReset Events needs to be manually reset. Otherwise,
* events will be automatically reset after a
* process waits for the event to finish.
* @param bInitialState Specifies whether the event is signalled or not
* initially.
*/
uint32 createEvent(bool bManualReset, bool bInitialState);
/**
* Destroy the given event.
* @param pidEvent Event Process ID.
*/
void closeEvent(uint32 pidEvent);
/**
* Set the event.
* @param pidEvent Event Process ID.
*/
void setEvent(uint32 pidEvent);
/**
* Reset the event.
* @param pidEvent Event Process ID.
*/
void resetEvent(uint32 pidEvent);
/**
* Temporarily set a given event to true, and then run all waiting
* processes, allowing any processes waiting on the event to be fired. It
* then immediately resets the event again.
*
* @param pidEvent Event Process ID.
*
* @remarks Should not be run inside of another process.
*/
void pulseEvent(uint32 pidEvent);
};
/** @} */
/** @} */
} // end of namespace Common
#endif // COMMON_COROUTINES_H