dvander@372: /**
dvander@375: * vim: set ts=4 :
ds@1330: * =============================================================================
dvander@1226: * SourceMod
ds@1947: * Copyright (C) 2004-2008 AlliedModders LLC. All rights reserved.
ds@1330: * =============================================================================
dvander@372: *
ds@1330: * This program is free software; you can redistribute it and/or modify it under
ds@1330: * the terms of the GNU General Public License, version 3.0, as published by the
ds@1330: * Free Software Foundation.
dvander@379: *
ds@1330: * This program is distributed in the hope that it will be useful, but WITHOUT
ds@1330: * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
ds@1330: * FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
ds@1330: * details.
dvander@1226: *
ds@1330: * You should have received a copy of the GNU General Public License along with
ds@1330: * this program. If not, see .
dvander@1226: *
ds@1330: * As a special exception, AlliedModders LLC gives you permission to link the
ds@1330: * code of this program (as well as its derivative works) to "Half-Life 2," the
ds@1330: * "Source Engine," the "SourcePawn JIT," and any Game MODs that run on software
ds@1330: * by the Valve Corporation. You must obey the GNU General Public License in
ds@1330: * all respects for all other code used. Additionally, AlliedModders LLC grants
ds@1330: * this exception to all derivative works. AlliedModders LLC defines further
ds@1330: * exceptions, found in LICENSE.txt (as of this writing, version JULY-31-2007),
ds@1330: * or .
dvander@372: *
dvander@372: * Version: $Id$
dvander@372: */
dvander@372:
dvander@324: #ifndef _INCLUDE_SOURCEMOD_FORWARDINTERFACE_H_
dvander@324: #define _INCLUDE_SOURCEMOD_FORWARDINTERFACE_H_
dvander@324:
dvander@372: /**
dvander@372: * @file IForwardSys.h
dvander@372: * @brief Defines the interface for managing collections ("forwards") of plugin calls.
dvander@372: *
dvander@372: * The Forward System is responsible for managing automated collections of IPluginFunctions.
dvander@372: * It thus provides wrappers to calling many functions at once. There are two types of such
dvander@372: * wrappers: Managed and Unmanaged. Confusingly, these terms refer to whether the user manages
dvander@372: * the forwards, not Core. Managed forwards are completely managed by the user, and are custom
dvander@372: * editable collections. Unmanaged forwards are the opposite, and will only work on a single global
dvander@372: * function name in all plugins.
dvander@372: */
dvander@372:
dvander@324: #include
dvander@327: #include
dvander@327:
dvander@327: using namespace SourcePawn;
dvander@324:
dvander@324: #define SMINTERFACE_FORWARDMANAGER_NAME "IForwardManager"
ds@2182: #define SMINTERFACE_FORWARDMANAGER_VERSION 3
dvander@324:
dvander@372: /*
dvander@324: * There is some very important documentation at the bottom of this file.
dvander@324: * Readers interested in knowing more about the forward system, scrolling down is a must!
dvander@324: */
dvander@324:
dvander@324: namespace SourceMod
dvander@324: {
dvander@372: /**
dvander@372: * @brief Defines the event hook result types plugins can return.
dvander@372: */
dvander@324: enum ResultType
dvander@324: {
dvander@372: Pl_Continue = 0, /**< No result */
faluco@1735: Pl_Changed = 1, /**< Inputs or outputs have been overridden with new values */
dvander@481: Pl_Handled = 3, /**< Result was handled, stop at the end */
dvander@481: Pl_Stop = 4, /**< Result was handled, stop now */
dvander@324: };
dvander@324:
dvander@372: /**
dvander@372: * @brief Defines how a forward iterates through plugin functions.
dvander@372: */
dvander@324: enum ExecType
dvander@324: {
dvander@372: ET_Ignore = 0, /**< Ignore all return values, return 0 */
dvander@372: ET_Single = 1, /**< Only return the last exec, ignore all others */
dvander@372: ET_Event = 2, /**< Acts as an event with the ResultTypes above, no mid-Stops allowed, returns highest */
dvander@372: ET_Hook = 3, /**< Acts as a hook with the ResultTypes above, mid-Stops allowed, returns highest */
ds@2181: ET_LowEvent = 4, /**< Same as ET_Event except that it returns the lowest value */
dvander@324: };
dvander@324:
dvander@324: class IForward;
ds@2181: class IForwardFilter;
dvander@324:
dvander@324: /**
dvander@372: * @brief Unmanaged Forward, abstracts calling multiple functions as "forwards," or collections of functions.
dvander@324: *
dvander@372: * Parameters should be pushed in forward order, unlike the virtual machine/IPluginContext order.
dvander@372: * Some functions are repeated in here because their documentation differs from their IPluginFunction equivalents.
dvander@372: * Missing are the Push functions, whose only doc change is that they throw SP_ERROR_PARAM on type mismatches.
dvander@324: */
dvander@324: class IForward : public ICallable
dvander@324: {
dvander@324: public:
dvander@372: /** Virtual Destructor */
dvander@324: virtual ~IForward()
dvander@324: {
dvander@324: }
dvander@324: public:
dvander@324: /**
dvander@324: * @brief Returns the name of the forward.
dvander@324: *
dvander@324: * @return Forward name.
dvander@324: */
dvander@615: virtual const char *GetForwardName() =0;
dvander@324:
dvander@324: /**
dvander@324: * @brief Returns the number of functions in this forward.
dvander@324: *
dvander@324: * @return Number of functions in forward.
dvander@324: */
dvander@615: virtual unsigned int GetFunctionCount() =0;
dvander@324:
dvander@324: /**
dvander@324: * @brief Returns the method of multi-calling this forward has.
dvander@324: *
dvander@324: * @return ExecType of the forward.
dvander@324: */
dvander@615: virtual ExecType GetExecType() =0;
dvander@324:
dvander@324: /**
dvander@324: * @brief Executes the forward.
dvander@324: *
dvander@447: * @param result Optional pointer to store result in.
ds@2181: * @param filter Do not use.
dvander@324: * @return Error code, if any.
dvander@324: */
dvander@324: virtual int Execute(cell_t *result, IForwardFilter *filter=NULL) =0;
dvander@324:
dvander@324: /**
dvander@324: * @brief Pushes an array of cells onto the current call. Different rules than ICallable.
dvander@324: * NOTE: On Execute, the pointer passed will be modified according to the copyback rule.
dvander@324: *
dvander@324: * @param inarray Array to copy. Cannot be NULL, unlike ICallable's version.
dvander@324: * @param cells Number of cells to allocate and optionally read from the input array.
dvander@324: * @param flags Whether or not changes should be copied back to the input array.
dvander@324: * @return Error code, if any.
dvander@324: */
dvander@589: virtual int PushArray(cell_t *inarray, unsigned int cells, int flags=0) =0;
dvander@324: };
dvander@324:
dvander@372: /**
dvander@372: * @brief Managed Forward, same as IForward, except the collection can be modified.
dvander@372: */
dvander@324: class IChangeableForward : public IForward
dvander@324: {
dvander@324: public:
dvander@324: /**
dvander@324: * @brief Removes a function from the call list.
dvander@324: * NOTE: Only removes one instance.
dvander@324: *
dvander@324: * @param func Function to remove.
dvander@324: * @return Whether or not the function was removed.
dvander@324: */
dvander@324: virtual bool RemoveFunction(IPluginFunction *func) =0;
dvander@324:
dvander@324: /**
dvander@324: * @brief Removes all instances of a plugin from the call list.
dvander@324: *
dvander@324: * @param plugin Plugin to remove instances of.
dvander@324: * @return Number of functions removed therein.
dvander@324: */
dvander@324: virtual unsigned int RemoveFunctionsOfPlugin(IPlugin *plugin) =0;
dvander@324:
dvander@324: /**
dvander@324: * @brief Adds a function to the call list.
ds@729: * NOTE: Cannot be used during an incomplete call.
dvander@324: * NOTE: If used during a call, function is temporarily queued until calls are over.
ds@729: * NOTE: Adding multiple copies of the same function is illegal.
dvander@324: *
dvander@324: * @param func Function to add.
dvander@324: * @return True on success, otherwise false.
dvander@324: */
dvander@324: virtual bool AddFunction(IPluginFunction *func) =0;
dvander@324:
dvander@324: /**
dvander@324: * @brief Adds a function to the call list.
ds@729: * NOTE: Cannot be used during an incomplete call.
dvander@324: * NOTE: If used during a call, function is temporarily queued until calls are over.
dvander@324: *
dvander@324: * @param ctx Context to use as a look-up.
dvander@372: * @param index Function id to add.
dvander@324: * @return True on success, otherwise false.
dvander@324: */
dvander@327: virtual bool AddFunction(IPluginContext *ctx, funcid_t index) =0;
ds@621:
ds@621: /**
faluco@682: * @brief Removes a function from the call list.
faluco@682: * NOTE: Only removes one instance.
faluco@682: *
faluco@682: * @param ctx Context to use as a look-up.
faluco@682: * @param index Function id to add.
faluco@682: * @return Whether or not the function was removed.
faluco@682: */
ds@621: virtual bool RemoveFunction(IPluginContext *ctx, funcid_t index) =0;
dvander@324: };
dvander@324:
dvander@324: #define SP_PARAMTYPE_ANY 0
dvander@324: #define SP_PARAMFLAG_BYREF (1<<0)
dvander@324: #define SP_PARAMTYPE_CELL (1<<1)
dvander@324: #define SP_PARAMTYPE_FLOAT (2<<1)
dvander@324: #define SP_PARAMTYPE_STRING (3<<1)|SP_PARAMFLAG_BYREF
dvander@324: #define SP_PARAMTYPE_ARRAY (4<<1)|SP_PARAMFLAG_BYREF
dvander@324: #define SP_PARAMTYPE_VARARG (5<<1)
dvander@324:
dvander@372: /**
dvander@372: * @brief Describes the various ways to pass parameters to plugins.
dvander@372: */
dvander@324: enum ParamType
dvander@324: {
dvander@372: Param_Any = SP_PARAMTYPE_ANY, /**< Any data type can be pushed */
dvander@372: Param_Cell = SP_PARAMTYPE_CELL, /**< Only basic cells can be pushed */
dvander@372: Param_Float = SP_PARAMTYPE_FLOAT, /**< Only floats can be pushed */
dvander@372: Param_String = SP_PARAMTYPE_STRING, /**< Only strings can be pushed */
dvander@372: Param_Array = SP_PARAMTYPE_ARRAY, /**< Only arrays can be pushed */
dvander@372: Param_VarArgs = SP_PARAMTYPE_VARARG, /**< Same as "..." in plugins, anything can be pushed, but it will always be byref */
dvander@372: Param_CellByRef = SP_PARAMTYPE_CELL|SP_PARAMFLAG_BYREF, /**< Only a cell by reference can be pushed */
dvander@372: Param_FloatByRef = SP_PARAMTYPE_FLOAT|SP_PARAMFLAG_BYREF, /**< Only a float by reference can be pushed */
dvander@324: };
dvander@324:
dvander@372: /**
dvander@372: * @brief Provides functions for creating/destroying managed and unmanaged forwards.
dvander@372: */
dvander@324: class IForwardManager : public SMInterface
dvander@324: {
dvander@324: public:
dvander@324: virtual const char *GetInterfaceName()
dvander@324: {
dvander@324: return SMINTERFACE_FORWARDMANAGER_NAME;
dvander@324: }
dvander@324: virtual unsigned int GetInterfaceVersion()
dvander@324: {
dvander@324: return SMINTERFACE_FORWARDMANAGER_VERSION;
dvander@324: }
dvander@589: virtual bool IsVersionCompatible(unsigned int version)
dvander@589: {
dvander@589: if (version < 2 || version > GetInterfaceVersion())
dvander@589: {
dvander@589: return false;
dvander@589: }
dvander@589: return true;
dvander@589: }
dvander@324: public:
dvander@324: /**
dvander@324: * @brief Creates a managed forward. This forward exists globally.
dvander@324: * The name used to create the forward is used as its public function in all target plugins.
dvander@324: * As new non-private plugins become loaded or unloaded, they will be automatically added
dvander@324: * or removed. This is ideal for global, static forwards that are never changed.
dvander@324: *
dvander@324: * @param name Name of public function to use in forward.
dvander@324: * @param et Execution type to be used.
dvander@324: * @param num_params Number of parameter this function will have.
dvander@324: * NOTE: For varargs, this should include the vararg parameter.
dvander@324: * @param types Array of type information about each parameter. If NULL, types
dvander@324: * are read off the vararg stream.
dvander@324: * @param ... If types is NULL, num_params ParamTypes should be pushed.
dvander@324: * @return A new IForward on success, NULL if type combination is impossible.
dvander@324: */
dvander@324: virtual IForward *CreateForward(const char *name,
dvander@324: ExecType et,
dvander@324: unsigned int num_params,
ds@559: const ParamType *types,
dvander@324: ...) =0;
dvander@324:
dvander@324: /**
dvander@324: * @brief Creates an unmanaged forward. This forward exists privately.
dvander@324: * Unlike managed forwards, no functions are ever added by the Manager.
dvander@324: * However, functions will be removed automatically if their parent plugin is unloaded.
dvander@324: *
dvander@324: * @param name Name of forward (unused except for lookup, can be NULL for anonymous).
dvander@324: * @param et Execution type to be used.
dvander@324: * @param num_params Number of parameter this function will have.
dvander@324: * NOTE: For varargs, this should include the vararg parameter.
dvander@324: * @param types Array of type information about each parameter. If NULL, types
dvander@324: * are read off the vararg stream.
dvander@324: * @param ... If types is NULL, num_params ParamTypes should be pushed.
dvander@324: * @return A new IChangeableForward on success, NULL if type combination is impossible.
dvander@324: */
dvander@324: virtual IChangeableForward *CreateForwardEx(const char *name,
dvander@324: ExecType et,
dvander@324: int num_params,
ds@559: const ParamType *types,
dvander@324: ...) =0;
dvander@324:
dvander@324: /**
dvander@324: * @brief Finds a forward by name. Does not return anonymous forwards (named NULL or "").
dvander@324: *
dvander@324: * @param name Name of forward.
dvander@324: * @param ifchng Optionally store either NULL or an IChangeableForward pointer
dvander@324: * depending on type of forward.
dvander@324: * @return IForward pointer, or NULL if none found matching the name.
dvander@324: */
dvander@324: virtual IForward *FindForward(const char *name, IChangeableForward **ifchng) =0;
dvander@324:
dvander@324: /**
dvander@324: * @brief Frees and destroys a forward object.
dvander@324: *
dvander@324: * @param forward An IForward created by CreateForward() or CreateForwardEx().
dvander@324: */
dvander@324: virtual void ReleaseForward(IForward *forward) =0;
dvander@324: };
ds@432: }
dvander@324:
dvander@372: /*
dvander@324: * In the AMX Mod X model of forwarding, each forward contained a list of pairs, each pair containing
dvander@324: * a function ID and an AMX structure. The forward structure itself did very little but hold parameter types.
dvander@324: * An execution call worked like this:
dvander@324: * - executeForward() took in a function id and a list of parameters
dvander@324: * - for each contained plugin:
dvander@324: * - the list of parameters was preprocessed and pushed
dvander@324: * - the call was made
dvander@324: * - the list was freed and copybacks were made
dvander@324: * - return
dvander@324: *
dvander@324: * The advantages to this is that the system is very easy to implement, and it's fast. The disadvantage is
dvander@324: * varargs tend to be very unforgiving and inflexible, and thus weird problems arose with casting. You also
dvander@324: * lose flexibility, type checking, and the ability to reasonably use variable arguments lists in the VM.
dvander@324: *
dvander@324: * SourceMod replaces this forward system with a far more advanced, but a bit bulkier one. The idea is that
dvander@324: * each plugin has a table of functions, and each function is an ICallable object. As well as being an ICallable,
dvander@324: * each function is an IPluginFunction. An ICallable simply describes the process of adding parameters to a
dvander@324: * function call. An IPluginFunction describes the process of actually calling a function and performing allocation,
dvander@324: * copybacks, and deallocations.
dvander@324: *
dvander@324: * A very powerful forward system emerges: a Forward is just a collection of IPluginFunctions. Thus, the same
dvander@324: * API can be easily wrapped around a simple list, and it will look transparent to the user.
dvander@324: * Advantages:
dvander@324: * 1) "SP Forwards" from AMX Mod X are simply IPluginFunctions without a collection.
dvander@324: * 2) Forwards are function based, rather than plugin based, and are thus far more flexible at runtime..
dvander@324: * 3) [2] Individual functions can be paused and more than one function from the same plugin can be hooked.
dvander@324: * 4) [2] One hook type that used to map to many SP Forwards can now be centralized as one Forward.
dvander@324: * This helps alleviate messes like Fakemeta.
dvander@324: * 5) Parameter pushing is type-checked and allows for variable arguments.
dvander@324: *
dvander@324: * Note that while #2,3,4 could be added to AMX Mod X, the real binding property is #1, which makes the system
dvander@324: * object oriented, rather than AMX Mod X, which hides the objects behind static functions. It is entirely a design
dvander@324: * issue, rather than a usability one. The interesting part is when it gets to implementation, which has to cache
dvander@324: * parameter pushing until execution. Without this, multiple function calls can be started across one plugin, which
dvander@324: * will result in heap corruption given SourcePawn's implementation.
dvander@324: *
dvander@324: * Observe the new calling process:
dvander@324: * - Each parameter is pushed into a local cache using the ICallable interface.
dvander@324: * - For each function in the collection:
dvander@324: * - Each parameter is decoded and -pushed into the function.
dvander@324: * - The call is made.
dvander@324: * - Return
dvander@324: *
dvander@324: * Astute readers will note the (minor) problems:
dvander@324: * 1) More memory is used. Specifically, rather than N params of memory, you now have N params * M plugins.
dvander@324: * This is because, again, parameters are cached both per-function and per-forward.
dvander@324: * 2) There are slightly more calls going around: one extra call for each parameter, since each push is manual.
dvander@324: *
dvander@324: * HISTORICAL NOTES:
dvander@324: * There used to be a # about copy backs.
dvander@324: * Note that originally, the Forward implementation was a thin wrapper around IForwards. It did not cache pushes,
dvander@324: * and instead immediately fired them to each internal plugin. This was to allow users to know that pointers would
dvander@324: * be immediately resolved. Unfortunately, this became extremely burdensome on the API and exposed many problems,
dvander@324: * the major (and breaking) one was that two separate Function objects cannot be in a calling process on the same
dvander@324: * plugin at once. (:TODO: perhaps prevent that in the IPlugin object?) This is because heap functions lose their order
ds@432: * and become impossible to re-arrange without some global heap tracking mechanism. It also made iterative copy backs
dvander@324: * for arrays/references overwhelmingly complex, since each plugin had to have its memory back-patched for each copy.
dvander@324: * Therefore, this was scrapped for cached parameters (current implementation), which is the implementation AMX Mod X
dvander@324: * uses. It is both faster and works better.
dvander@324: */
dvander@324:
dvander@324: #endif //_INCLUDE_SOURCEMOD_FORWARDINTERFACE_H_