1 | /* |
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2 | * EMFCache.java |
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3 | * |
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4 | * Copyright (C) 2003-2006 Peter Graves, 2013 Rudolf Schlatte |
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5 | * |
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6 | * This program is free software; you can redistribute it and/or |
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7 | * modify it under the terms of the GNU General Public License |
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8 | * as published by the Free Software Foundation; either version 2 |
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9 | * of the License, or (at your option) any later version. |
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10 | * |
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11 | * This program is distributed in the hope that it will be useful, |
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12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
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13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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14 | * GNU General Public License for more details. |
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15 | * |
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16 | * You should have received a copy of the GNU General Public License |
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17 | * along with this program; if not, write to the Free Software |
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18 | * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. |
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19 | * |
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20 | * As a special exception, the copyright holders of this library give you |
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21 | * permission to link this library with independent modules to produce an |
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22 | * executable, regardless of the license terms of these independent |
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23 | * modules, and to copy and distribute the resulting executable under |
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24 | * terms of your choice, provided that you also meet, for each linked |
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25 | * independent module, the terms and conditions of the license of that |
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26 | * module. An independent module is a module which is not derived from |
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27 | * or based on this library. If you modify this library, you may extend |
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28 | * this exception to your version of the library, but you are not |
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29 | * obligated to do so. If you do not wish to do so, delete this |
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30 | * exception statement from your version. |
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31 | */ |
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32 | |
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33 | package org.armedbear.lisp; |
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34 | |
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35 | import static org.armedbear.lisp.Lisp.*; |
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36 | |
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37 | import java.util.concurrent.ConcurrentHashMap; |
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38 | |
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39 | public final class EMFCache extends LispObject |
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40 | { |
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41 | ConcurrentHashMap<CacheEntry,LispObject> cache |
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42 | = new ConcurrentHashMap<CacheEntry,LispObject>();; |
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43 | EqlSpecialization eqlSpecializations[] = new EqlSpecialization[0]; |
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44 | |
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45 | void clearCache() |
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46 | { |
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47 | cache = new ConcurrentHashMap<CacheEntry,LispObject>(); |
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48 | } |
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49 | |
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50 | @Override |
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51 | public String printObject() |
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52 | { |
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53 | return unreadableString("EMF-CACHE"); |
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54 | } |
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55 | |
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56 | static final FuncallableStandardObject checkStandardGenericFunction(LispObject obj) |
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57 | { |
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58 | if (obj instanceof FuncallableStandardObject) |
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59 | return (FuncallableStandardObject) obj; |
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60 | return (FuncallableStandardObject) // Not reached. |
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61 | type_error(obj, Symbol.STANDARD_GENERIC_FUNCTION); |
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62 | } |
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63 | |
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64 | private static class EqlSpecialization extends LispObject |
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65 | { |
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66 | public LispObject eqlTo; |
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67 | |
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68 | public EqlSpecialization(LispObject eqlTo) |
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69 | { |
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70 | this.eqlTo = eqlTo; |
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71 | } |
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72 | } |
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73 | |
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74 | private static class CacheEntry |
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75 | { |
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76 | final LispObject[] array; |
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77 | |
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78 | CacheEntry(LispObject[] array) |
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79 | { |
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80 | this.array = array; |
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81 | } |
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82 | |
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83 | @Override |
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84 | public int hashCode() |
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85 | { |
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86 | int result = 0; |
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87 | for (int i = array.length; i-- > 0;) |
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88 | result ^= array[i].hashCode(); |
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89 | return result; |
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90 | } |
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91 | |
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92 | @Override |
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93 | public boolean equals(Object object) |
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94 | { |
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95 | if (!(object instanceof CacheEntry)) |
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96 | return false; |
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97 | final CacheEntry otherEntry = (CacheEntry) object; |
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98 | if (otherEntry.array.length != array.length) |
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99 | return false; |
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100 | final LispObject[] otherArray = otherEntry.array; |
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101 | for (int i = array.length; i-- > 0;) |
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102 | if (array[i] != otherArray[i]) |
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103 | return false; |
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104 | return true; |
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105 | } |
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106 | } |
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107 | |
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108 | private static final Primitive _MAKE_EMF_CACHE |
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109 | = new pf__make_emf_cache(); |
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110 | @DocString(name="%make-emf-cache") |
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111 | private static final class pf__make_emf_cache extends Primitive |
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112 | { |
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113 | pf__make_emf_cache() |
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114 | { |
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115 | super("%make-emf-cache", PACKAGE_SYS, true); |
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116 | } |
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117 | @Override |
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118 | public LispObject execute(LispObject arg) |
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119 | { |
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120 | return new EMFCache(); |
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121 | } |
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122 | }; |
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123 | |
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124 | private static final Primitive _REINIT_EMF_CACHE |
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125 | = new pf__reinit_emf_cache(); |
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126 | @DocString(name="%reinit-emf-cache", |
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127 | args="generic-function eql-specilizer-objects-list") |
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128 | private static final class pf__reinit_emf_cache extends Primitive |
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129 | { |
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130 | pf__reinit_emf_cache() |
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131 | { |
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132 | super("%reinit-emf-cache", PACKAGE_SYS, true, |
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133 | "generic-function eql-specializer-objects-list"); |
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134 | } |
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135 | @Override |
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136 | public LispObject execute(LispObject generic_function, LispObject eql_specializers) |
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137 | { |
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138 | final FuncallableStandardObject gf = checkStandardGenericFunction(generic_function); |
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139 | EMFCache cache = gf.cache; |
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140 | cache.clearCache(); |
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141 | cache.eqlSpecializations = new EqlSpecialization[eql_specializers.length()]; |
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142 | for (int i = 0; i < cache.eqlSpecializations.length; i++) { |
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143 | cache.eqlSpecializations[i] = new EqlSpecialization(eql_specializers.car()); |
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144 | eql_specializers = eql_specializers.cdr(); |
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145 | } |
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146 | return T; |
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147 | } |
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148 | }; |
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149 | |
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150 | private static final Primitive CACHE_EMF |
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151 | = new pf_cache_emf(); |
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152 | @DocString(name="cache-emf", |
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153 | args="generic-function args emf") |
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154 | private static final class pf_cache_emf extends Primitive |
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155 | { |
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156 | pf_cache_emf() |
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157 | { |
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158 | super("cache-emf", PACKAGE_SYS, true, "generic-function args emf"); |
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159 | } |
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160 | @Override |
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161 | public LispObject execute(LispObject first, LispObject second, |
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162 | LispObject third) |
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163 | { |
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164 | final FuncallableStandardObject gf = checkStandardGenericFunction(first); |
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165 | EMFCache cache = gf.cache; |
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166 | LispObject args = second; |
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167 | int numberOfRequiredArgs |
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168 | = gf.getInstanceSlotValue(Symbol.REQUIRED_ARGS).length(); |
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169 | LispObject[] array = new LispObject[numberOfRequiredArgs]; |
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170 | for (int i = numberOfRequiredArgs; i-- > 0;) |
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171 | { |
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172 | array[i] = cache.getArgSpecialization(args.car()); |
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173 | args = args.cdr(); |
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174 | } |
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175 | CacheEntry specializations = new CacheEntry(array); |
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176 | ConcurrentHashMap<CacheEntry,LispObject> ht = cache.cache; |
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177 | ht.put(specializations, third); |
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178 | return third; |
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179 | } |
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180 | }; |
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181 | |
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182 | private static final Primitive GET_CACHED_EMF |
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183 | = new pf_get_cached_emf(); |
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184 | @DocString(name="get-cached-emf", |
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185 | args="generic-function args") |
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186 | private static final class pf_get_cached_emf extends Primitive |
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187 | { |
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188 | pf_get_cached_emf() { |
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189 | super("get-cached-emf", PACKAGE_SYS, true, "generic-function args"); |
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190 | } |
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191 | @Override |
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192 | public LispObject execute(LispObject first, LispObject second) |
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193 | { |
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194 | final FuncallableStandardObject gf = checkStandardGenericFunction(first); |
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195 | EMFCache cache = gf.cache; |
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196 | LispObject args = second; |
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197 | int numberOfRequiredArgs |
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198 | = gf.getInstanceSlotValue(Symbol.REQUIRED_ARGS).length(); |
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199 | LispObject[] array = new LispObject[numberOfRequiredArgs]; |
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200 | for (int i = numberOfRequiredArgs; i-- > 0;) |
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201 | { |
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202 | array[i] = cache.getArgSpecialization(args.car()); |
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203 | args = args.cdr(); |
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204 | } |
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205 | CacheEntry specializations = new CacheEntry(array); |
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206 | ConcurrentHashMap<CacheEntry,LispObject> ht = cache.cache; |
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207 | LispObject emf = (LispObject) ht.get(specializations); |
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208 | return emf != null ? emf : NIL; |
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209 | } |
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210 | }; |
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211 | |
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212 | /** |
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213 | * Returns an object representing generic function |
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214 | * argument <tt>arg</tt> in a <tt>CacheEntry</tt> |
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215 | * |
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216 | * <p>In the simplest case, when this generic function |
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217 | * does not have EQL specialized methods, and therefore |
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218 | * only argument types are relevant for choosing |
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219 | * applicable methods, the value returned is the |
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220 | * class of <tt>arg</tt> |
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221 | * |
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222 | * <p>If the function has EQL specialized methods: |
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223 | * - if <tt>arg</tt> is EQL to some of the EQL-specializers, |
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224 | * a special object representing equality to that specializer |
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225 | * is returned. |
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226 | * - otherwise class of the <tt>arg</tt> is returned. |
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227 | * |
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228 | * <p>Note that we do not consider argument position, when |
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229 | * calculating arg specialization. In rare cases (when one argument |
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230 | * is eql-specialized to a symbol specifying class of another |
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231 | * argument) this may result in redundant cache entries caching the |
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232 | * same method. But the method cached is anyway correct for the |
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233 | * arguments (because in case of cache miss, correct method is |
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234 | * calculated by other code, which does not rely on |
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235 | * getArgSpecialization; and because EQL is true only for objects of |
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236 | * the same type, which guaranties that if a type-specialized |
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237 | * methods was chached by eql-specialization, all the cache hits |
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238 | * into this records will be from args of the conforming type). |
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239 | * |
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240 | * <p>Consider: |
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241 | * <pre><tt> |
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242 | * (defgeneric f (a b)) |
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243 | * |
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244 | * (defmethod f (a (b (eql 'symbol))) |
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245 | * "T (EQL 'SYMBOL)") |
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246 | * |
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247 | * (defmethod f ((a symbol) (b (eql 'symbol))) |
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248 | * "SYMBOL (EQL 'SYMBOL)") |
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249 | * |
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250 | * (f 12 'symbol) |
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251 | * => "T (EQL 'SYMBOL)" |
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252 | * |
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253 | * (f 'twelve 'symbol) |
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254 | * => "SYMBOL (EQL 'SYMBOL)" |
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255 | * |
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256 | * (f 'symbol 'symbol) |
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257 | * => "SYMBOL (EQL 'SYMBOL)" |
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258 | * |
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259 | * </tt></pre> |
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260 | * |
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261 | * After the two above calls <tt>cache</tt> will contain three keys: |
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262 | * <pre> |
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263 | * { class FIXNUM, EqlSpecialization('SYMBOL) } |
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264 | * { class SYMBOL, EqlSpecialization('SYMBOL) } |
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265 | * { EqlSpecialization('SYMBOL), EqlSpecialization('SYMBOL) }. |
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266 | * </pre> |
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267 | */ |
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268 | LispObject getArgSpecialization(LispObject arg) |
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269 | { |
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270 | for (EqlSpecialization eqlSpecialization : eqlSpecializations) |
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271 | { |
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272 | if (eqlSpecialization.eqlTo.eql(arg)) |
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273 | return eqlSpecialization; |
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274 | } |
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275 | return arg.classOf(); |
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276 | } |
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277 | |
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278 | } |
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