/** Implementation of functions for dissecting/making method calls Copyright (C) 1994, 1995, 1996, 1997, 1998 Free Software Foundation, Inc. Written by: Andrew Kachites McCallum Created: Oct 1994 This file is part of the GNUstep Base Library. This library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. This library 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 Library General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with this library; if not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02111 USA. */ /* These functions can be used for dissecting and making method calls for many different situations. They are used for distributed objects; they could also be used to make interfaces between Objective C and Scheme, Perl, Tcl, or other languages. */ /* Remove `inline' nested functions if they crash your compiler */ //#define inline #include "config.h" #include "GNUstepBase/preface.h" #ifdef HAVE_ALLOCA_H #include #endif #include #include #include #include /* Deal with strrchr: */ #if STDC_HEADERS || defined(HAVE_STRING_H) #include /* An ANSI string.h and pre-ANSI memory.h might conflict. */ #if !STDC_HEADERS && defined(HAVE_MEMORY_H) #include #endif /* not STDC_HEADERS and HAVE_MEMORY_H */ #define index strchr #define rindex strrchr #define bcopy(s, d, n) memcpy ((d), (s), (n)) #define bcmp(s1, s2, n) memcmp ((s1), (s2), (n)) #define bzero(s, n) memset ((s), 0, (n)) #else /* not STDC_HEADERS and not HAVE_STRING_H */ #include /* memory.h and strings.h conflict on some systems. */ #endif /* not STDC_HEADERS and not HAVE_STRING_H */ #include "Foundation/NSObjCRuntime.h" #include "Foundation/NSData.h" #include "Foundation/NSException.h" #include "Foundation/NSDebug.h" /* For encoding and decoding the method arguments, we have to know where to find things in the "argframe" as returned by __builtin_apply_args. For some situations this is obvious just from the selector type encoding, but structures passed by value cause a problem because some architectures actually pass these by reference, i.e. use the structure-value-address mentioned in the gcc/config/_/_.h files. These differences are not encoded in the selector types. Below is my current guess for which architectures do this. xxx I really should do this properly by looking at the gcc config values. I've also been told that some architectures may pass structures with sizef(structure) > sizeof(void*) by reference, but pass smaller ones by value. The code doesn't currently handle that case. */ char* mframe_build_signature(const char *typePtr, int *size, int *narg, char *buf) { MFRAME_ARGS cum; BOOL doMalloc = NO; const char *types; char *start; char *dest; int total = 0; int count = 0; /* * If we have not been given a buffer - allocate space on the stack for * the largest concievable type encoding. */ if (buf == 0) { doMalloc = YES; buf = alloca((strlen(typePtr)+1)*16); } /* * Copy the return type info (including qualifiers) into the buffer. */ types = objc_skip_typespec(typePtr); strncpy(buf, typePtr, types - typePtr); buf[types-typePtr] = '\0'; /* * Point to the return type, initialise size of stack args, and skip * to the first argument. */ types = objc_skip_type_qualifiers(typePtr); MFRAME_INIT_ARGS(cum, types); types = objc_skip_typespec(types); if (*types == '+') { types++; } if (*types == '-') { types++; } while (isdigit(*types)) { types++; } /* * Where to start putting encoding information - leave enough room for * the size of the stack args to be stored after the return type. */ start = &buf[strlen(buf)+10]; dest = start; /* * Now step through all the arguments - copy any type qualifiers, but * let the macro write all the other info into the buffer. */ while (types && *types) { const char *qual = types; /* * If there are any type qualifiers - copy the through to the * destination. */ types = objc_skip_type_qualifiers(types); while (qual < types) { *dest++ = *qual++; } MFRAME_ARG_ENCODING(cum, types, total, dest); count++; } *dest = '\0'; /* * Write the total size of the stack arguments after the return type, * then copy the remaining type information to fill the gap. */ sprintf(&buf[strlen(buf)], "%d", total); dest = &buf[strlen(buf)]; while (*start) { *dest++ = *start++; } *dest = '\0'; /* * If we have written into a local buffer - we need to allocate memory * in which to return our result. */ if (doMalloc) { char *tmp = NSZoneMalloc(NSDefaultMallocZone(), dest - buf + 1); strcpy(tmp, buf); buf = tmp; } /* * If the caller wants to know the total size of the stack and/or the * number of arguments, return them in the appropriate variables. */ if (size) { *size = total; } if (narg) { *narg = count; } return buf; } /* Step through method encoding information extracting details. * If outTypes is non-nul then we copy the argument type into * the buffer as a nul terminated string and use the values in * this buffer as the types in info, rather than pointers to * positions in typePtr */ const char * mframe_next_arg(const char *typePtr, NSArgumentInfo *info, char *outTypes) { NSArgumentInfo local; BOOL flag; BOOL negative = NO; if (info == 0) { info = &local; } /* * Skip past any type qualifiers - if the caller wants them, return them. */ flag = YES; info->qual = 0; while (flag) { switch (*typePtr) { case _C_CONST: info->qual |= _F_CONST; break; case _C_IN: info->qual |= _F_IN; break; case _C_INOUT: info->qual |= _F_INOUT; break; case _C_OUT: info->qual |= _F_OUT; break; case _C_BYCOPY: info->qual |= _F_BYCOPY; break; #ifdef _C_BYREF case _C_BYREF: info->qual |= _F_BYREF; break; #endif case _C_ONEWAY: info->qual |= _F_ONEWAY; break; #ifdef _C_GCINVISIBLE case _C_GCINVISIBLE: info->qual |= _F_GCINVISIBLE; break; #endif default: flag = NO; } if (flag) { typePtr++; } } info->type = typePtr; /* * Scan for size and alignment information. */ switch (*typePtr++) { case _C_ID: info->size = sizeof(id); info->align = __alignof__(id); break; case _C_CLASS: info->size = sizeof(Class); info->align = __alignof__(Class); break; case _C_SEL: info->size = sizeof(SEL); info->align = __alignof__(SEL); break; case _C_CHR: info->size = sizeof(char); info->align = __alignof__(char); break; case _C_UCHR: info->size = sizeof(unsigned char); info->align = __alignof__(unsigned char); break; case _C_SHT: info->size = sizeof(short); info->align = __alignof__(short); break; case _C_USHT: info->size = sizeof(unsigned short); info->align = __alignof__(unsigned short); break; case _C_INT: info->size = sizeof(int); info->align = __alignof__(int); break; case _C_UINT: info->size = sizeof(unsigned int); info->align = __alignof__(unsigned int); break; case _C_LNG: info->size = sizeof(long); info->align = __alignof__(long); break; case _C_ULNG: info->size = sizeof(unsigned long); info->align = __alignof__(unsigned long); break; case _C_LNG_LNG: info->size = sizeof(long long); info->align = __alignof__(long long); break; case _C_ULNG_LNG: info->size = sizeof(unsigned long long); info->align = __alignof__(unsigned long long); break; case _C_FLT: info->size = sizeof(float); info->align = __alignof__(float); break; case _C_DBL: info->size = sizeof(double); info->align = __alignof__(double); break; case _C_PTR: info->size = sizeof(char*); info->align = __alignof__(char*); if (*typePtr == '?') { typePtr++; } else { typePtr = objc_skip_typespec(typePtr); } break; case _C_ATOM: case _C_CHARPTR: info->size = sizeof(char*); info->align = __alignof__(char*); break; case _C_ARY_B: { int length = atoi(typePtr); while (isdigit(*typePtr)) { typePtr++; } typePtr = mframe_next_arg(typePtr, &local, 0); info->size = length * ROUND(local.size, local.align); info->align = local.align; typePtr++; /* Skip end-of-array */ } break; case _C_STRUCT_B: { unsigned int acc_size = 0; unsigned int def_align = objc_alignof_type(typePtr-1); unsigned int acc_align = def_align; const char *ptr = typePtr; /* * Skip "=" stuff. */ while (*ptr != _C_STRUCT_E && *ptr != '=') ptr++; if (*ptr == '=') typePtr = ptr; typePtr++; /* * Base structure alignment on first element. */ if (*typePtr != _C_STRUCT_E) { typePtr = mframe_next_arg(typePtr, &local, 0); if (typePtr == 0) { return 0; /* error */ } acc_size = ROUND(acc_size, local.align); acc_size += local.size; acc_align = MAX(local.align, def_align); } /* * Continue accumulating structure size * and adjust alignment if necessary */ while (*typePtr != _C_STRUCT_E) { typePtr = mframe_next_arg(typePtr, &local, 0); if (typePtr == 0) { return 0; /* error */ } acc_size = ROUND(acc_size, local.align); acc_size += local.size; acc_align = MAX(local.align, acc_align); } /* * Size must be a multiple of alignment */ if (acc_size % acc_align != 0) { acc_size += acc_align - acc_size % acc_align; } info->size = acc_size; info->align = acc_align; typePtr++; /* Skip end-of-struct */ } break; case _C_UNION_B: { unsigned int max_size = 0; unsigned int max_align = 0; /* * Skip "=" stuff. */ while (*typePtr != _C_UNION_E) { if (*typePtr++ == '=') { break; } } while (*typePtr != _C_UNION_E) { typePtr = mframe_next_arg(typePtr, &local, 0); if (typePtr == 0) { return 0; /* error */ } max_size = MAX(max_size, local.size); max_align = MAX(max_align, local.align); } info->size = max_size; info->align = max_align; typePtr++; /* Skip end-of-union */ } break; case _C_VOID: info->size = 0; info->align = __alignof__(char*); break; default: return 0; } if (typePtr == 0) { /* Error condition. */ return 0; } /* Copy tye type information into the buffer if provided. */ if (outTypes != 0) { unsigned len = typePtr - info->type; strncpy(outTypes, info->type, len); outTypes[len] = '\0'; info->type = outTypes; } /* * May tell the caller if the item is stored in a register. */ if (*typePtr == '+') { typePtr++; info->isReg = YES; } else { info->isReg = NO; } /* * Cope with negative offsets. */ if (*typePtr == '-') { typePtr++; negative = YES; } /* * May tell the caller what the stack/register offset is for * this argument. */ info->offset = 0; while (isdigit(*typePtr)) { info->offset = info->offset * 10 + (*typePtr++ - '0'); } if (negative == YES) { info->offset = -info->offset; } return typePtr; } /* Return the number of arguments that the method MTH expects. Note that all methods need two implicit arguments `self' and `_cmd'. */ int method_types_get_number_of_arguments (const char *type) { int i = 0; while (*type) { type = objc_skip_argspec (type); i += 1; } return i - 1; } /* Return the size of the argument block needed on the stack to invoke the method MTH. This may be zero, if all arguments are passed in registers. */ int method_types_get_size_of_stack_arguments (const char *type) { type = objc_skip_typespec (type); return atoi (type); } int method_types_get_size_of_register_arguments(const char *types) { const char* type = strrchr(types, '+'); if (type) { return atoi(++type) + sizeof(void*); } else { return 0; } } /* To fix temporary bug in method_get_next_argument() on NeXT boxes */ /* xxx Perhaps this isn't working with the NeXT runtime? */ char* method_types_get_next_argument (arglist_t argf, const char **type) { const char *t = objc_skip_argspec (*type); arglist_t argframe; argframe = (void*)argf; if (*t == '\0') { return 0; } *type = t; t = objc_skip_typespec (t); if (*t == '+') { return argframe->arg_regs + atoi(++t); } else { /* xxx What's going on here? This -8 needed on my 68k NeXT box. */ #if NeXT return argframe->arg_ptr + (atoi(t) - 8); #else return argframe->arg_ptr + atoi(t); #endif } } char* method_types_get_first_argument (struct objc_method* m, arglist_t argframe, const char** type) { *type = m->method_types; return method_types_get_next_argument (argframe, type); } int method_types_get_sizeof_arguments (struct objc_method* mth) { const char* type = objc_skip_typespec (mth->method_types); return atoi (type); } /* mframe_dissect_call() This function encodes the arguments of a method call. Call it with an ARGFRAME that was returned by __builtin_args(), and a TYPE string that describes the input and return locations, i.e. from sel_get_types() or Method->method_types. The function ENCODER will be called once with each input argument. Returns YES iff there are any outparameters---parameters that for which we will have to get new values after the method is run, e.g. an argument declared (out char*). */ BOOL mframe_dissect_call (arglist_t argframe, const char *type, void (*encoder)(DOContext *), DOContext *ctxt) { unsigned flags; char *datum; int argnum; BOOL out_parameters = NO; if (*type == _C_STRUCT_B || *type == _C_UNION_B || *type == _C_ARY_B) { datum = alloca((strlen(type)+1)*10); type = mframe_build_signature(type, 0, 0, datum); } /* Enumerate all the arguments in ARGFRAME, and call ENCODER for each one. METHOD_TYPES_GET_NEXT_ARGUEMENT() returns 0 when there are no more arguments, otherwise it returns a pointer to the argument in the ARGFRAME. */ for (datum = method_types_get_next_argument(argframe, &type), argnum=0; datum; datum = method_types_get_next_argument(argframe, &type), argnum++) { /* Get the type qualifiers, like IN, OUT, INOUT, ONEWAY. */ flags = objc_get_type_qualifiers(type); /* Skip over the type qualifiers, so now TYPE is pointing directly at the char corresponding to the argument's type, as defined in */ type = objc_skip_type_qualifiers(type); /* Decide how, (or whether or not), to encode the argument depending on its FLAGS and TYPE. Only the first two cases involve parameters that may potentially be passed by reference, and thus only the first two may change the value of OUT_PARAMETERS. */ ctxt->type = type; ctxt->flags = flags; ctxt->datum = datum; switch (*type) { case _C_CHARPTR: /* Handle a (char*) argument. */ /* If the char* is qualified as an OUT parameter, or if it not explicitly qualified as an IN parameter, then we will have to get this char* again after the method is run, because the method may have changed it. Set OUT_PARAMETERS accordingly. */ if ((flags & _F_OUT) || !(flags & _F_IN)) out_parameters = YES; /* If the char* is qualified as an IN parameter, or not explicity qualified as an OUT parameter, then encode it. */ if ((flags & _F_IN) || !(flags & _F_OUT)) (*encoder) (ctxt); break; case _C_PTR: /* If the pointer's value is qualified as an OUT parameter, or if it not explicitly qualified as an IN parameter, then we will have to get the value pointed to again after the method is run, because the method may have changed it. Set OUT_PARAMETERS accordingly. */ if ((flags & _F_OUT) || !(flags & _F_IN)) out_parameters = YES; /* Handle an argument that is a pointer to a non-char. But (void*) and (anything**) is not allowed. */ /* The argument is a pointer to something; increment TYPE so we can see what it is a pointer to. */ type++; ctxt->type = type; ctxt->datum = *(void**)datum; /* If the pointer's value is qualified as an IN parameter, or not explicity qualified as an OUT parameter, then encode it. */ if ((flags & _F_IN) || !(flags & _F_OUT)) (*encoder) (ctxt); break; case _C_STRUCT_B: case _C_UNION_B: case _C_ARY_B: /* Handle struct and array arguments. */ /* Whether DATUM points to the data, or points to a pointer that points to the data, depends on the value of MFRAME_STRUCT_BYREF. Do the right thing so that ENCODER gets a pointer to directly to the data. */ #if MFRAME_STRUCT_BYREF ctxt->datum = *(void**)datum; #endif (*encoder) (ctxt); break; default: /* Handle arguments of all other types. */ (*encoder) (ctxt); } } /* Return a BOOL indicating whether or not there are parameters that were passed by reference; we will need to get those values again after the method has finished executing because the execution of the method may have changed them.*/ return out_parameters; } /* mframe_do_call() This function decodes the arguments of method call, builds an argframe of type arglist_t, and invokes the method using __builtin_apply; then it encodes the return value and any pass-by-reference arguments. ENCODED_TYPES should be a string that describes the return value and arguments. It's argument types and argument type qualifiers should match exactly those that were used when the arguments were encoded with mframe_dissect_call()---mframe_do_call() uses ENCODED_TYPES to determine which variable types it should decode. ENCODED_TYPES is used to get the types and type qualifiers, but not to get the register and stack locations---we get that information from the selector type of the SEL that is decoded as the second argument. In this way, the ENCODED_TYPES may come from a machine of a different architecture. Having the original ENCODED_TYPES is good, just in case the machine running mframe_do_call() has some slightly different qualifiers. Using different qualifiers for encoding and decoding could lead to massive confusion. DECODER should be a pointer to a function that obtains the method's argument values. For example: void my_decoder (int argnum, void *data, const char *type) ARGNUM is the number of the argument, beginning at 0. DATA is a pointer to the memory where the value should be placed. TYPE is a pointer to the type string of this value. mframe_do_call() calls this function once for each of the methods arguments. The DECODER function should place the ARGNUM'th argument's value at the memory location DATA. mframe_do_call() calls this function once with ARGNUM -1, DATA 0, and TYPE 0 to denote completion of decoding. If DECODER malloc's new memory in the course of doing its business, then DECODER is responsible for making sure that the memory will get free eventually. For example, if DECODER uses -decodeValueOfCType:at:withName: to decode a char* string, you should remember that -decodeValueOfCType:at:withName: malloc's new memory to hold the string, and DECODER should autorelease the malloc'ed pointer, using the NSData class. ENCODER should be a pointer to a function that records the method's return value and pass-by-reference values. For example: void my_encoder (int argnum, void *data, const char *type, int flags) ARGNUM is the number of the argument; this will be -1 for the return value, and the argument index for the pass-by-reference values; the indices start at 0. DATA is a pointer to the memory where the value can be found. TYPE is a pointer to the type string of this value. FLAGS is a copy of the type qualifier flags for this argument; (see ). mframe_do_call() calls this function after the method has been run---once for the return value, and once for each of the pass-by-reference parameters. The ENCODER function should place the value at memory location DATA wherever the user wants to record the ARGNUM'th return value. PASS_POINTERS is a flag saying whether pointers should be passed as pointers (for local stuff) or should be assumed to point to a single data item (for distributed objects). */ static inline id retframe_id(void *rframe) { __builtin_return (rframe); } static inline Class retframe_Class(void *rframe) { __builtin_return (rframe); } static inline SEL retframe_SEL(void *rframe) { __builtin_return (rframe); } static inline unsigned long retframe_long(void *rframe) { __builtin_return (rframe); } static inline unsigned long long retframe_longlong(void *rframe) { __builtin_return (rframe); } static inline char* retframe_pointer(void *rframe) { __builtin_return (rframe); } typedef struct { char val[4]; } block; static inline block retframe_block(void *rframe) { __builtin_return (rframe); } static inline float retframe_float (void *rframe) { __builtin_return (rframe); } /* For extracting a return value of type `double' from RETFRAME. */ static inline double retframe_double (void *rframe) { __builtin_return (rframe); } /* For extracting a return value of type `char' from RETFRAME */ static inline char retframe_char (void *rframe) { __builtin_return (rframe); } static inline short retframe_short (void *rframe) { __builtin_return (rframe); } static inline int retframe_int (void *rframe) { __builtin_return (rframe); } void mframe_do_call (DOContext *ctxt, void(*decoder)(DOContext*), void(*encoder)(DOContext*)) { /* The method type string obtained from the target's OBJC_METHOD structure for the selector we're sending. */ const char *type; /* A pointer into the local variable TYPE string. */ const char *tmptype; /* A pointer into the argument ENCODED_TYPES string. */ const char *etmptype; /* The target object that will receive the message. */ id object; /* The selector for the message we're sending to the TARGET. */ SEL selector; /* The OBJECT's Method(_t) pointer for the SELECTOR. */ GSMethod meth = 0; /* The OBJECT's implementation of the SELECTOR. */ IMP method_implementation; /* The number bytes for holding arguments passed on the stack. */ int stack_argsize; /* The number bytes for holding arguments passed in registers. */ int reg_argsize; /* The structure for holding the arguments to the method. */ arglist_t argframe; /* A pointer into the ARGFRAME; points at individual arguments. */ char *datum; /* Type qualifier flags; see . */ unsigned flags; /* Which argument number are we processing now? */ int argnum; /* A pointer to the memory holding the return value of the method. */ void *retframe; /* Does the method have any arguments that are passed by reference? If so, we need to encode them, since the method may have changed them. */ BOOL out_parameters = NO; const char *encoded_types = ctxt->type; /* Decode the object, (which is always the first argument to a method), into the local variable OBJECT. */ ctxt->datum = &object; ctxt->type = @encode(id); (*decoder) (ctxt); NSCParameterAssert (object); /* Decode the selector, (which is always the second argument to a method), into the local variable SELECTOR. */ /* xxx @encode(SEL) produces "^v" in gcc 2.5.8. It should be ":" */ ctxt->datum = &selector; ctxt->type = @encode(SEL); (*decoder) (ctxt); NSCParameterAssert (selector); /* Get the "selector type" for this method. The "selector type" is a string that lists the return and argument types, and also indicates in which registers and where on the stack the arguments should be placed before the method call. The selector type string we get here should have the same argument and return types as the ENCODED_TYPES string, but it will have different register and stack locations if the ENCODED_TYPES came from a machine of a different architecture. */ if (GSObjCIsClass(object)) { meth = GSGetMethod(object, selector, NO, YES); } else if (GSObjCIsInstance(object)) { meth = GSGetMethod(GSObjCClass(object), selector, YES, YES); } else { [NSException raise: NSInvalidArgumentException format: @"decoded object %p is invalid", object]; } if (meth != 0) { type = meth->method_types; } else { NSDebugLog(@"Local object <%p %s> doesn't implement: %s directly. " @"Will search for arbitrary signature.", object, GSNameFromClass(GSObjCIsClass(object) ? object : (id) GSObjCClass(object)), GSNameFromSelector(selector)); type = GSTypesFromSelector(selector); } /* Make sure we successfully got the method type, and that its types match the ENCODED_TYPES. */ NSCParameterAssert (type); NSCParameterAssert (GSSelectorTypesMatch(encoded_types, type)); /* * The compiler/runtime doesn't always seem to get the encoding right * for our purposes - so we generate our own encoding as required by * __builtin_apply(). */ if (*type == _C_STRUCT_B || *type == _C_UNION_B || *type == _C_ARY_B) { tmptype = alloca((strlen(type)+1)*10); type = mframe_build_signature(type, 0, 0, (char*)tmptype); } /* Allocate an argframe, using memory on the stack */ /* Calculate the amount of memory needed for storing variables that are passed in registers, and the amount of memory for storing variables that are passed on the stack. */ stack_argsize = method_types_get_size_of_stack_arguments (type); reg_argsize = method_types_get_size_of_register_arguments (type); /* Allocate the space for variables passed in registers. */ argframe = (arglist_t) alloca(sizeof(char*) + reg_argsize); /* Allocate the space for variables passed on the stack. */ if (stack_argsize) argframe->arg_ptr = alloca (stack_argsize); else argframe->arg_ptr = 0; if (*type == _C_STRUCT_B || *type == _C_UNION_B || *type == _C_ARY_B) { void *buf; /* If we are passing a pointer to return a structure in, we must allocate the memory for it and put it in the correct place in the argframe. */ buf = alloca(objc_sizeof_type(type)); MFRAME_SET_STRUCT_ADDR(argframe, type, buf); } /* Put OBJECT and SELECTOR into the ARGFRAME. */ /* Initialize our temporary pointers into the method type strings. */ tmptype = type; etmptype = objc_skip_argspec (encoded_types); /* Get a pointer into ARGFRAME, pointing to the location where the first argument is to be stored. */ datum = method_types_get_next_argument (argframe, &tmptype); NSCParameterAssert (datum); NSCParameterAssert (*tmptype == _C_ID); /* Put the target object there. */ *(id*)datum = object; /* Get a pointer into ARGFRAME, pointing to the location where the second argument is to be stored. */ etmptype = objc_skip_argspec(etmptype); datum = method_types_get_next_argument(argframe, &tmptype); NSCParameterAssert (datum); NSCParameterAssert (*tmptype == _C_SEL); /* Put the selector there. */ *(SEL*)datum = selector; /* Decode arguments after OBJECT and SELECTOR, and put them into the ARGFRAME. Step TMPTYPE and ETMPTYPE in lock-step through their method type strings. */ for (datum = method_types_get_next_argument (argframe, &tmptype), etmptype = objc_skip_argspec (etmptype), argnum = 2; datum; datum = method_types_get_next_argument (argframe, &tmptype), etmptype = objc_skip_argspec (etmptype), argnum++) { /* Get the type qualifiers, like IN, OUT, INOUT, ONEWAY. */ flags = objc_get_type_qualifiers (etmptype); /* Skip over the type qualifiers, so now TYPE is pointing directly at the char corresponding to the argument's type, as defined in */ tmptype = objc_skip_type_qualifiers(tmptype); /* Decide how, (or whether or not), to decode the argument depending on its FLAGS and TMPTYPE. Only the first two cases involve parameters that may potentially be passed by reference, and thus only the first two may change the value of OUT_PARAMETERS. *** Note: This logic must match exactly the code in mframe_dissect_call(); that function should encode exactly what we decode here. *** */ ctxt->type = tmptype; ctxt->datum = datum; switch (*tmptype) { case _C_CHARPTR: /* Handle a (char*) argument. */ /* If the char* is qualified as an OUT parameter, or if it not explicitly qualified as an IN parameter, then we will have to get this char* again after the method is run, because the method may have changed it. Set OUT_PARAMETERS accordingly. */ if ((flags & _F_OUT) || !(flags & _F_IN)) out_parameters = YES; /* If the char* is qualified as an IN parameter, or not explicity qualified as an OUT parameter, then decode it. Note: the decoder allocates memory for holding the string, and it is also responsible for making sure that the memory gets freed eventually, (usually through the autorelease of NSData object). */ if ((flags & _F_IN) || !(flags & _F_OUT)) (*decoder) (ctxt); break; case _C_PTR: /* If the pointer's value is qualified as an OUT parameter, or if it not explicitly qualified as an IN parameter, then we will have to get the value pointed to again after the method is run, because the method may have changed it. Set OUT_PARAMETERS accordingly. */ if ((flags & _F_OUT) || !(flags & _F_IN)) out_parameters = YES; /* Handle an argument that is a pointer to a non-char. But (void*) and (anything**) is not allowed. */ /* The argument is a pointer to something; increment TYPE so we can see what it is a pointer to. */ tmptype++; /* Allocate some memory to be pointed to, and to hold the value. Note that it is allocated on the stack, and methods that want to keep the data pointed to, will have to make their own copies. */ *(void**)datum = alloca (objc_sizeof_type (tmptype)); /* If the pointer's value is qualified as an IN parameter, or not explicity qualified as an OUT parameter, then decode it. */ ctxt->type = tmptype; ctxt->datum = *(void**)datum; if ((flags & _F_IN) || !(flags & _F_OUT)) (*decoder) (ctxt); break; case _C_STRUCT_B: case _C_UNION_B: case _C_ARY_B: /* Handle struct and array arguments. */ /* Whether DATUM points to the data, or points to a pointer that points to the data, depends on the value of MFRAME_STRUCT_BYREF. Do the right thing so that ENCODER gets a pointer to directly to the data. */ #if MFRAME_STRUCT_BYREF /* Allocate some memory to be pointed to, and to hold the data. Note that it is allocated on the stack, and methods that want to keep the data pointed to, will have to make their own copies. */ *(void**)datum = alloca (objc_sizeof_type(tmptype)); ctxt->datum = datum; #endif (*decoder) (ctxt); break; default: /* Handle arguments of all other types. */ /* NOTE FOR OBJECTS: Unlike [Decoder decodeObjectAt:..], this function does not generate a reference to the object; the object may be autoreleased; if the method wants to keep a reference to the object, it will have to -retain it. */ (*decoder) (ctxt); } } /* End of the for () loop that enumerates the method's arguments. */ ctxt->type = 0; ctxt->datum = 0; (*decoder) (ctxt); /* Invoke the method! */ /* Find the target object's implementation of this selector. */ method_implementation = objc_msg_lookup (object, selector); NSCParameterAssert (method_implementation); /* Do it! Send the message to the target, and get the return value in RETFRAME. The arguments will still be in ARGFRAME, so we can get the pass-by-reference info from there. */ retframe = __builtin_apply((void(*)(void))method_implementation, argframe, stack_argsize); /* Encode the return value and pass-by-reference values, if there are any. This logic must match exactly that in mframe_build_return(). */ /* OUT_PARAMETERS should be true here in exactly the same situations as it was true in mframe_dissect_call(). */ /* Get the qualifier type of the return value. */ flags = objc_get_type_qualifiers (encoded_types); /* Get the return type; store it our two temporary char*'s. */ etmptype = objc_skip_type_qualifiers (encoded_types); tmptype = objc_skip_type_qualifiers (type); /* Only encode return values if there is a non-void return value, a non-oneway void return value, or if there are values that were passed by reference. */ ctxt->type = tmptype; ctxt->datum = retframe; ctxt->flags = flags; /* If there is a return value, encode it. */ switch (*tmptype) { case _C_VOID: if ((flags & _F_ONEWAY) == 0) { int dummy = 0; ctxt->datum = &dummy; ctxt->type = @encode(int); (*encoder) (ctxt); } /* No return value to encode; do nothing. */ break; case _C_PTR: /* The argument is a pointer to something; increment TYPE so we can see what it is a pointer to. */ tmptype++; ctxt->type = tmptype; ctxt->datum = *(void**)retframe; /* Encode the value that was pointed to. */ (*encoder) (ctxt); break; case _C_STRUCT_B: case _C_UNION_B: case _C_ARY_B: /* The argument is a structure or array returned by value. (In C, are array's allowed to be returned by value?) */ ctxt->datum = MFRAME_GET_STRUCT_ADDR(argframe, tmptype); (*encoder)(ctxt); break; case _C_FLT: { float ret = retframe_float (retframe); ctxt->datum = &ret; (*encoder) (ctxt); break; } case _C_DBL: { double ret = retframe_double (retframe); ctxt->datum = &ret; (*encoder) (ctxt); break; } case _C_SHT: case _C_USHT: /* On some (but not all) architectures, for C variable types smaller than int, like short, the RETFRAME doesn't actually point to the beginning of the short, it points to the beginning of an int. So we let RETFRAME_SHORT() take care of it. */ { short ret = retframe_short (retframe); ctxt->datum = &ret; (*encoder) (ctxt); break; } case _C_CHR: case _C_UCHR: /* On some (but not all) architectures, for C variable types smaller than int, like char, the RETFRAME doesn't actually point to the beginning of the char, it points to the beginning of an int. So we let RETFRAME_SHORT() take care of it. */ { char ret = retframe_char (retframe); ctxt->datum = &ret; (*encoder) (ctxt); break; } default: /* case _C_INT: case _C_UINT: case _C_LNG: case _C_ULNG: case _C_CHARPTR: case: _C_ID: */ /* xxx I think this assumes that sizeof(int)==sizeof(void*) */ (*encoder) (ctxt); } /* Encode the values returned by reference. Note: this logic must match exactly the code in mframe_build_return(); that function should decode exactly what we encode here. */ if (out_parameters) { /* Step through all the arguments, finding the ones that were passed by reference. */ for (datum = method_types_get_next_argument (argframe, &tmptype), argnum = 1, etmptype = objc_skip_argspec (etmptype); datum; datum = method_types_get_next_argument (argframe, &tmptype), argnum++, etmptype = objc_skip_argspec (etmptype)) { /* Get the type qualifiers, like IN, OUT, INOUT, ONEWAY. */ flags = objc_get_type_qualifiers(etmptype); /* Skip over the type qualifiers, so now TYPE is pointing directly at the char corresponding to the argument's type, as defined in */ tmptype = objc_skip_type_qualifiers (tmptype); ctxt->type = tmptype; ctxt->datum = datum; /* Decide how, (or whether or not), to encode the argument depending on its FLAGS and TMPTYPE. */ if ((*tmptype == _C_PTR) && ((flags & _F_OUT) || !(flags & _F_IN))) { /* The argument is a pointer (to a non-char), and the pointer's value is qualified as an OUT parameter, or it not explicitly qualified as an IN parameter, then it is a pass-by-reference argument.*/ /* The argument is a pointer to something; increment TYPE so we can see what it is a pointer to. */ tmptype++; ctxt->type = tmptype; ctxt->datum = *(void**)datum; /* Encode it. */ (*encoder) (ctxt); } else if (*tmptype == _C_CHARPTR && ((flags & _F_OUT) || !(flags & _F_IN))) { /* The argument is a pointer char string, and the pointer's value is qualified as an OUT parameter, or it not explicitly qualified as an IN parameter, then it is a pass-by-reference argument. Encode it.*/ /* xxx Perhaps we could save time and space by saving a copy of the string before the method call, and then comparing it to this string; if it didn't change, don't bother to send it back again. */ (*encoder) (ctxt); } } } return; } #if 0 /* For returning structures etc */ typedef struct { id many[8];} __big; static __big return_block (void* data) { return *(__big*)data; } #endif /* For returning a char (or unsigned char) */ static char return_char (char data) { return data; } /* For returning a double */ static double return_double (double data) { return data; } /* For returning a float */ static float return_float (float data) { return data; } /* For returning a short (or unsigned short) */ static short return_short (short data) { return data; } #if 0 static retval_t apply_block(void* data) { void* args = __builtin_apply_args(); return __builtin_apply((apply_t)return_block, args, sizeof(void*)); } #endif static retval_t apply_char(char data) { void* args = __builtin_apply_args(); return __builtin_apply((apply_t)return_char, args, sizeof(void*)); } static retval_t apply_float(float data) { void* args = __builtin_apply_args(); return __builtin_apply((apply_t)return_float, args, sizeof(float)); } static retval_t apply_double(double data) { void* args = __builtin_apply_args(); return __builtin_apply((apply_t)return_double, args, sizeof(double)); } static retval_t apply_short(short data) { void* args = __builtin_apply_args(); return __builtin_apply((apply_t)return_short, args, sizeof(void*)); } /* mframe_build_return() This function decodes the values returned from a method call, builds a retframe of type retval_t that can be passed to GCC's __builtin_return(), and updates the pass-by-reference arguments in ARGFRAME. This function returns a retframe pointer. In the function that calls this one, be careful about calling more functions after this one. The memory for the retframe is alloca()'ed, and therefore is on the stack and can be tromped-on by future function calls. The callback function is finally called with the 'type' set to a null pointer to tell it that the return value and all return parameters have been dealt with. This permits the function to do any tidying up necessary. */ retval_t mframe_build_return (arglist_t argframe, const char *type, BOOL out_parameters, void(*decoder)(DOContext*), DOContext *ctxt) { /* A pointer to the memory that will hold the return value. */ retval_t retframe = NULL; /* The size, in bytes, of memory pointed to by RETFRAME. */ unsigned int retsize; /* Which argument number are we processing now? */ int argnum; /* Type qualifier flags; see . */ int flags; /* A pointer into the TYPE string. */ const char *tmptype; /* A pointer into the ARGFRAME; points at individual arguments. */ void *datum; const char *rettype; if (*type == _C_STRUCT_B || *type == _C_UNION_B || *type == _C_ARY_B) { tmptype = alloca((strlen(type)+1)*10); type = mframe_build_signature(type, 0, 0, (char*)tmptype); } /* Get the return type qualifier flags, and the return type. */ flags = objc_get_type_qualifiers(type); tmptype = objc_skip_type_qualifiers(type); rettype = tmptype; /* Decode the return value and pass-by-reference values, if there are any. OUT_PARAMETERS should be the value returned by mframe_dissect_call(). */ if (out_parameters || *tmptype != _C_VOID || (flags & _F_ONEWAY) == 0) /* xxx What happens with method declared "- (oneway) foo: (out int*)ip;" */ /* xxx What happens with method declared "- (in char *) bar;" */ /* xxx Is this right? Do we also have to check _F_ONEWAY? */ { /* If there is a return value, decode it, and put it in retframe. */ if (*tmptype != _C_VOID || (flags & _F_ONEWAY) == 0) { /* Get the size of the returned value. */ if (*tmptype == _C_VOID) retsize = sizeof(void*); else retsize = objc_sizeof_type (tmptype); /* Allocate memory on the stack to hold the return value. It should be at least 4 * sizeof(void*). */ /* xxx We need to test retsize's less than 4. Also note that if we return structures using a structure-value-address, we are potentially alloca'ing much more than we need here. */ /* xxx Find out about returning structures by reference on non--structure-value-address machines, and potentially just always alloca(RETFRAME_SIZE == sizeof(void*)*4) */ retframe = alloca (MAX(retsize, sizeof(void*)*4)); ctxt->type = tmptype; ctxt->datum = retframe; ctxt->flags = flags; switch (*tmptype) { case _C_PTR: { unsigned retLength; /* We are returning a pointer to something. */ /* Increment TYPE so we can see what it is a pointer to. */ tmptype++; retLength = (unsigned int)objc_sizeof_type(tmptype); /* Allocate memory to hold the value we're pointing to. */ *(void**)retframe = NSZoneMalloc(NSDefaultMallocZone(), retLength); /* We are responsible for making sure this memory gets free'd eventually. Ask NSData class to autorelease it. */ [NSData dataWithBytesNoCopy: *(void**)retframe length: retLength]; ctxt->type = tmptype; ctxt->datum = *(void**)retframe; /* Decode the return value into the memory we allocated. */ (*decoder) (ctxt); } break; case _C_STRUCT_B: case _C_UNION_B: case _C_ARY_B: /* The argument is a structure or array returned by value. (In C, are array's allowed to be returned by value?) */ *(void**)retframe = MFRAME_GET_STRUCT_ADDR(argframe, tmptype); /* Decode the return value into the memory we allocated. */ ctxt->datum = *(void**)retframe; (*decoder) (ctxt); break; case _C_FLT: case _C_DBL: (*decoder) (ctxt); break; case _C_VOID: { ctxt->type = @encode(int); (*decoder) (ctxt); } break; default: (*decoder) (ctxt); } } /* Decode the values returned by reference. Note: this logic must match exactly the code in mframe_do_call(); that function should decode exactly what we encode here. */ if (out_parameters) { /* Step through all the arguments, finding the ones that were passed by reference. */ for (datum = method_types_get_next_argument(argframe, &tmptype), argnum=0; datum; (datum = method_types_get_next_argument(argframe, &tmptype)), argnum++) { /* Get the type qualifiers, like IN, OUT, INOUT, ONEWAY. */ flags = objc_get_type_qualifiers(tmptype); /* Skip over the type qualifiers, so now TYPE is pointing directly at the char corresponding to the argument's type, as defined in */ tmptype = objc_skip_type_qualifiers(tmptype); /* Decide how, (or whether or not), to encode the argument depending on its FLAGS and TMPTYPE. */ if (*tmptype == _C_PTR && ((flags & _F_OUT) || !(flags & _F_IN))) { /* The argument is a pointer (to a non-char), and the pointer's value is qualified as an OUT parameter, or it not explicitly qualified as an IN parameter, then it is a pass-by-reference argument.*/ /* The argument is a pointer to something; increment TYPE so we can see what it is a pointer to. */ tmptype++; ctxt->flags = flags; ctxt->type = tmptype; ctxt->datum = *(void**)datum; /* xxx Note that a (char**) is malloc'ed anew here. Yucky, or worse than yucky. If the returned string is smaller than the original, we should just put it there; if the returned string is bigger, I don't know what to do. */ /* xxx __builtin_return can't return structures by value? */ (*decoder) (ctxt); } else if (*tmptype == _C_CHARPTR && ((flags & _F_OUT) || !(flags & _F_IN))) { /* The argument is a pointer char string, and the pointer's value is qualified as an OUT parameter, or it not explicitly qualified as an IN parameter, then it is a pass-by-reference argument. Encode it.*/ /* xxx Perhaps we could save time and space by saving a copy of the string before the method call, and then comparing it to this string; if it didn't change, don't bother to send it back again. */ ctxt->flags = flags; ctxt->type = tmptype; ctxt->datum = datum; (*decoder) (ctxt); } } } ctxt->type = 0; ctxt->datum = 0; (*decoder) (ctxt); /* Tell it we have finished. */ } else /* matches `if (out_parameters)' */ { /* We are just returning void, but retframe needs to point to something or else we can crash. */ retframe = alloca (sizeof(void*)); } switch (*rettype) { case _C_CHR: case _C_UCHR: return apply_char(*(char*)retframe); case _C_DBL: return apply_double(*(double*)retframe); case _C_FLT: return apply_float(*(float*)retframe); case _C_SHT: case _C_USHT: return apply_short(*(short*)retframe); #if 0 case _C_ARY_B: case _C_UNION_B: case _C_STRUCT_B: if (objc_sizeof_type(rettype) > 8) { return apply_block(*(void**)retframe); } #endif } /* Return the retval_t pointer to the return value. */ return retframe; } arglist_t mframe_create_argframe(const char *types, void** retbuf) { arglist_t argframe = objc_calloc(MFRAME_ARGS_SIZE, 1); const char* rtype = objc_skip_type_qualifiers(types); int stack_argsize = atoi(objc_skip_typespec(rtype)); /* * Allocate the space for variables passed on the stack. */ if (stack_argsize) { argframe->arg_ptr = objc_calloc(stack_argsize, 1); } else { argframe->arg_ptr = 0; } if (*rtype == _C_STRUCT_B || *rtype == _C_UNION_B || *rtype == _C_ARY_B) { /* * If we haven't been passed a pointer to the location in which * to store a returned structure - allocate space and return * the address of the allocated space. */ if (*retbuf == 0) { *retbuf = objc_calloc(objc_sizeof_type(rtype), 1); } MFRAME_SET_STRUCT_ADDR(argframe, rtype, *retbuf); } return argframe; } void mframe_destroy_argframe(const char *types, arglist_t argframe) { const char* rtype = objc_skip_type_qualifiers(types); int stack_argsize = atoi(objc_skip_typespec(rtype)); if (stack_argsize) { NSZoneFree(NSDefaultMallocZone(), argframe->arg_ptr); } NSZoneFree(NSDefaultMallocZone(), argframe); } BOOL mframe_decode_return (const char *type, void* buffer, void* retframe) { unsigned int size = 0; type = objc_skip_type_qualifiers(type); NSGetSizeAndAlignment(type, &size, 0); switch (*type) { case _C_ID: { *(id*)buffer = retframe_id(retframe); break; } case _C_CLASS: { *(Class*)buffer = retframe_Class(retframe); break; } case _C_SEL: { *(SEL*)buffer = retframe_SEL(retframe); break; } case _C_CHR: case _C_UCHR: { *(unsigned char*)buffer = retframe_char(retframe); break; } case _C_SHT: case _C_USHT: { *(unsigned short*)buffer = retframe_short(retframe); break; } case _C_INT: case _C_UINT: { *(unsigned int*)buffer = retframe_int(retframe); break; } case _C_LNG: case _C_ULNG: { *(unsigned long*)buffer = retframe_long(retframe); break; } case _C_LNG_LNG: case _C_ULNG_LNG: { *(unsigned long long*)buffer = retframe_longlong(retframe); break; } case _C_FLT: { *(float*)buffer = retframe_float(retframe); break; } case _C_DBL: { *(double*)buffer = retframe_double(retframe); break; } case _C_PTR: case _C_ATOM: case _C_CHARPTR: { *(char**)buffer = retframe_pointer(retframe); break; } case _C_ARY_B: case _C_STRUCT_B: case _C_UNION_B: { *(block*)buffer = retframe_block(retframe); break; } case _C_VOID: break; default: return NO; /* Unknown type. */ } return YES; } void* mframe_handle_return(const char* type, void* retval, arglist_t argframe) { retval_t retframe; retframe = alloca(MFRAME_RESULT_SIZE); switch (*type) { case _C_VOID: break; case _C_CHR: case _C_UCHR: return apply_char(*(char*)retval); case _C_DBL: return apply_double(*(double*)retval); case _C_FLT: return apply_float(*(float*)retval); case _C_SHT: case _C_USHT: return apply_short(*(short*)retval); case _C_ARY_B: case _C_UNION_B: case _C_STRUCT_B: { int size = objc_sizeof_type(type); #if 1 void *dest; dest = MFRAME_GET_STRUCT_ADDR(argframe, type); memcpy(dest, retval, size); #else if (size > 8) { return apply_block(*(void**)retval); } else { memcpy(retframe, retval, size); } #endif break; } default: memcpy(retframe, retval, objc_sizeof_type(type)); break; } return retframe; }