class.c

00001 /*
00002 # This file is Copyright 2009 Dean Hall.
00003 #
00004 # This file is part of the PyMite VM.
00005 # The PyMite VM is free software: you can redistribute it and/or modify
00006 # it under the terms of the GNU GENERAL PUBLIC LICENSE Version 2.
00007 #
00008 # The PyMite VM is distributed in the hope that it will be useful,
00009 # but WITHOUT ANY WARRANTY; without even the implied warranty of
00010 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
00011 # A copy of the GNU GENERAL PUBLIC LICENSE Version 2
00012 # is seen in the file COPYING in this directory.
00013 */
00014 
00015 
00016 #undef __FILE_ID__
00017 #define __FILE_ID__ 0x18
00018 
00019 
00020 /**
00021  * \file
00022  * \brief Class Object Type
00023  *
00024  * Class object type operations.
00025  */
00026 
00027 
00028 #include "pm.h"
00029 
00030 
00031 PmReturn_t
00032 class_new(pPmObj_t pattrs, pPmObj_t pbases, pPmObj_t pname, pPmObj_t *r_pclass)
00033 {
00034     PmReturn_t retval = PM_RET_OK;
00035     uint8_t *pchunk;
00036     pPmObj_t pobj;
00037 
00038     /* Ensure types */
00039     if ((OBJ_GET_TYPE(pattrs) != OBJ_TYPE_DIC)
00040         || (OBJ_GET_TYPE(pbases) != OBJ_TYPE_TUP)
00041         || (OBJ_GET_TYPE(pname) != OBJ_TYPE_STR))
00042     {
00043         PM_RAISE(retval, PM_RET_EX_TYPE);
00044         return retval;
00045     }
00046 
00047     /* Allocate a class obj */
00048     retval = heap_getChunk(sizeof(PmClass_t), &pchunk);
00049     PM_RETURN_IF_ERROR(retval);
00050     pobj = (pPmObj_t)pchunk;
00051     OBJ_SET_TYPE(pobj, OBJ_TYPE_CLO);
00052 
00053     /* Class has no access to its CO */
00054     ((pPmClass_t)pobj)->cl_attrs = (pPmDict_t)pattrs;
00055     ((pPmClass_t)pobj)->cl_bases = (pPmTuple_t)pbases;
00056 
00057     *r_pclass = pobj;
00058 
00059     return retval;
00060 }
00061 
00062 
00063 /* Returns an instance of the class by reference */
00064 PmReturn_t
00065 class_instantiate(pPmObj_t pclass, pPmObj_t *r_pobj)
00066 {
00067     PmReturn_t retval = PM_RET_OK;
00068     uint8_t *pchunk;
00069     pPmObj_t pobj;
00070     pPmObj_t pattrs;
00071 
00072     /* Allocate a class instance */
00073     retval = heap_getChunk(sizeof(PmInstance_t), &pchunk);
00074     PM_RETURN_IF_ERROR(retval);
00075     pobj = (pPmObj_t)pchunk;
00076     OBJ_SET_TYPE(pobj, OBJ_TYPE_CLI);
00077 
00078     /* Set the instance's class */
00079     ((pPmInstance_t)pobj)->cli_class = (pPmClass_t)pclass;
00080 
00081     /* Create the attributes dict */
00082     retval = dict_new(&pattrs);
00083     ((pPmInstance_t)pobj)->cli_attrs = (pPmDict_t)pattrs;
00084 
00085     /* TODO: Store pclass in __class__ attr */
00086 
00087     *r_pobj = pobj;
00088     return retval;
00089 }
00090 
00091 
00092 PmReturn_t
00093 class_method(pPmObj_t pinstance, pPmObj_t pfunc, pPmObj_t *r_pmeth)
00094 {
00095     PmReturn_t retval = PM_RET_OK;
00096     uint8_t *pchunk;
00097     pPmMethod_t pmeth;
00098     pPmObj_t pattrs;
00099 
00100     /* Allocate a method */
00101     retval = heap_getChunk(sizeof(PmMethod_t), &pchunk);
00102     PM_RETURN_IF_ERROR(retval);
00103     OBJ_SET_TYPE(pchunk, OBJ_TYPE_MTH);
00104 
00105     /* Set method fields */
00106     pmeth = (pPmMethod_t)pchunk;
00107     pmeth->m_instance = (pPmInstance_t)pinstance;
00108     pmeth->m_func = (pPmFunc_t)pfunc;
00109 
00110     /* Create the attributes dict */
00111     retval = dict_new(&pattrs);
00112     pmeth->m_attrs = (pPmDict_t)pattrs;
00113 
00114     *r_pmeth = (pPmObj_t)pmeth;
00115     return retval;
00116 }
00117 
00118 
00119 PmReturn_t
00120 class_getAttr(pPmObj_t pobj, pPmObj_t pname, pPmObj_t *r_pobj)
00121 {
00122     PmReturn_t retval;
00123     uint16_t i;
00124     pPmObj_t pparent;
00125 
00126     /* If the given obj is an instance, check its attrs */
00127     if (OBJ_GET_TYPE(pobj) == OBJ_TYPE_CLI)
00128     {
00129         retval = dict_getItem((pPmObj_t)((pPmInstance_t)pobj)->cli_attrs, pname,
00130                               r_pobj);
00131         if (retval == PM_RET_OK)
00132         {
00133             return retval;
00134         }
00135 
00136         /* Otherwise, check the instance's class */
00137         pobj = (pPmObj_t)((pPmInstance_t)pobj)->cli_class;
00138     }
00139 
00140     C_ASSERT(OBJ_GET_TYPE(pobj) == OBJ_TYPE_CLO);
00141 
00142     retval = dict_getItem((pPmObj_t)((pPmClass_t)pobj)->cl_attrs, pname,
00143                           r_pobj);
00144 
00145     /* If attr is not found, search parent(s) */
00146     if ((retval == PM_RET_EX_KEY) && (((pPmClass_t)pobj)->cl_bases != C_NULL))
00147     {
00148         for (i = 0; i < ((pPmClass_t)pobj)->cl_bases->length; i++)
00149         {
00150             pparent = ((pPmClass_t)pobj)->cl_bases->val[i];
00151             retval = class_getAttr(pparent, pname, r_pobj);
00152             if (retval == PM_RET_OK)
00153             {
00154                 break;
00155             }
00156         }
00157     }
00158 
00159     return retval;
00160 }
00161 
00162 
00163 uint8_t /* boolean */
00164 class_isSubclass(pPmObj_t ptest_class, pPmObj_t pbase_class)
00165 {
00166     uint8_t i;
00167     uint8_t retval;
00168 
00169     retval = C_FALSE;
00170 
00171     if (ptest_class == pbase_class)
00172     {
00173         return C_TRUE;
00174     }
00175 
00176     /* Recursively check if test class has a matching base class */
00177     if (((pPmClass_t)ptest_class)->cl_bases != C_NULL)
00178     {
00179         for (i = 0; i < ((pPmClass_t)ptest_class)->cl_bases->length; i++)
00180         {
00181             retval = class_isSubclass(((pPmClass_t)ptest_class)->cl_bases->val[i],
00182                                         pbase_class);
00183             if (retval)
00184             {
00185                 break;
00186             }
00187         }
00188     }
00189     return retval;
00190 }