1 /* |
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2 * Copyright (c) 2003, 2011, Oracle and/or its affiliates. All rights reserved. |
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3 * |
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4 * Redistribution and use in source and binary forms, with or without |
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5 * modification, are permitted provided that the following conditions |
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6 * are met: |
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7 * |
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8 * - Redistributions of source code must retain the above copyright |
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9 * notice, this list of conditions and the following disclaimer. |
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10 * |
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11 * - Redistributions in binary form must reproduce the above copyright |
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12 * notice, this list of conditions and the following disclaimer in the |
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13 * documentation and/or other materials provided with the distribution. |
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14 * |
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15 * - Neither the name of Oracle nor the names of its |
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16 * contributors may be used to endorse or promote products derived |
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17 * from this software without specific prior written permission. |
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18 * |
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19 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS |
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20 * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, |
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21 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR |
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22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR |
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23 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, |
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24 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, |
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25 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR |
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26 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF |
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27 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING |
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28 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS |
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29 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
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30 */ |
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31 |
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32 /* |
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33 * This source code is provided to illustrate the usage of a given feature |
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34 * or technique and has been deliberately simplified. Additional steps |
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35 * required for a production-quality application, such as security checks, |
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36 * input validation and proper error handling, might not be present in |
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37 * this sample code. |
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38 */ |
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39 |
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40 |
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41 /* The Class Loader table. */ |
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42 |
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43 /* |
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44 * The Class Loader objects show up so early in the VM process that a |
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45 * separate table was designated for Class Loaders. |
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46 * |
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47 * The Class Loader is unique by way of it's jobject uniqueness, unfortunately |
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48 * use of JNI too early for jobject comparisons is problematic. |
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49 * It is assumed that the number of class loaders will be limited, and |
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50 * a simple linear search will be performed for now. |
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51 * That logic is isolated here and can be changed to use the standard |
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52 * table hash table search once we know JNI can be called safely. |
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53 * |
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54 * A weak global reference is created to keep tabs on loaders, and as |
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55 * each search for a loader happens, NULL weak global references will |
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56 * trigger the freedom of those entries. |
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57 * |
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58 */ |
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59 |
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60 #include "hprof.h" |
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61 |
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62 typedef struct { |
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63 jobject globalref; /* Weak Global reference for object */ |
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64 ObjectIndex object_index; |
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65 } LoaderInfo; |
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66 |
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67 static LoaderInfo * |
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68 get_info(LoaderIndex index) |
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69 { |
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70 return (LoaderInfo*)table_get_info(gdata->loader_table, index); |
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71 } |
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72 |
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73 static void |
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74 delete_globalref(JNIEnv *env, LoaderInfo *info) |
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75 { |
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76 jobject ref; |
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77 |
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78 HPROF_ASSERT(env!=NULL); |
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79 HPROF_ASSERT(info!=NULL); |
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80 ref = info->globalref; |
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81 info->globalref = NULL; |
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82 if ( ref != NULL ) { |
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83 deleteWeakGlobalReference(env, ref); |
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84 } |
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85 info->object_index = 0; |
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86 } |
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87 |
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88 static void |
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89 cleanup_item(TableIndex index, void *key_ptr, int key_len, |
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90 void *info_ptr, void *arg) |
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91 { |
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92 } |
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93 |
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94 static void |
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95 delete_ref_item(TableIndex index, void *key_ptr, int key_len, |
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96 void *info_ptr, void *arg) |
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97 { |
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98 delete_globalref((JNIEnv*)arg, (LoaderInfo*)info_ptr); |
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99 } |
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100 |
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101 static void |
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102 list_item(TableIndex index, void *key_ptr, int key_len, |
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103 void *info_ptr, void *arg) |
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104 { |
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105 LoaderInfo *info; |
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106 |
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107 HPROF_ASSERT(info_ptr!=NULL); |
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108 |
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109 info = (LoaderInfo*)info_ptr; |
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110 debug_message( "Loader 0x%08x: globalref=%p, object_index=%d\n", |
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111 index, (void*)info->globalref, info->object_index); |
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112 } |
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113 |
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114 static void |
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115 free_entry(JNIEnv *env, LoaderIndex index) |
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116 { |
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117 LoaderInfo *info; |
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118 |
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119 info = get_info(index); |
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120 delete_globalref(env, info); |
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121 table_free_entry(gdata->loader_table, index); |
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122 } |
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123 |
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124 typedef struct SearchData { |
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125 JNIEnv *env; |
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126 jobject loader; |
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127 LoaderIndex found; |
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128 } SearchData; |
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129 |
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130 static void |
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131 search_item(TableIndex index, void *key_ptr, int key_len, void *info_ptr, void *arg) |
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132 { |
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133 LoaderInfo *info; |
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134 SearchData *data; |
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135 |
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136 HPROF_ASSERT(info_ptr!=NULL); |
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137 HPROF_ASSERT(arg!=NULL); |
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138 info = (LoaderInfo*)info_ptr; |
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139 data = (SearchData*)arg; |
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140 if ( data->loader == info->globalref ) { |
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141 /* Covers when looking for NULL too. */ |
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142 HPROF_ASSERT(data->found==0); /* Did we find more than one? */ |
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143 data->found = index; |
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144 } else if ( data->env != NULL && data->loader != NULL && |
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145 info->globalref != NULL ) { |
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146 jobject lref; |
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147 |
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148 lref = newLocalReference(data->env, info->globalref); |
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149 if ( lref == NULL ) { |
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150 /* Object went away, free reference and entry */ |
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151 free_entry(data->env, index); |
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152 } else if ( isSameObject(data->env, data->loader, lref) ) { |
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153 HPROF_ASSERT(data->found==0); /* Did we find more than one? */ |
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154 data->found = index; |
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155 } |
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156 if ( lref != NULL ) { |
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157 deleteLocalReference(data->env, lref); |
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158 } |
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159 } |
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160 |
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161 } |
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162 |
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163 static LoaderIndex |
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164 search(JNIEnv *env, jobject loader) |
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165 { |
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166 SearchData data; |
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167 |
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168 data.env = env; |
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169 data.loader = loader; |
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170 data.found = 0; |
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171 table_walk_items(gdata->loader_table, &search_item, (void*)&data); |
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172 return data.found; |
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173 } |
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174 |
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175 LoaderIndex |
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176 loader_find_or_create(JNIEnv *env, jobject loader) |
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177 { |
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178 LoaderIndex index; |
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179 |
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180 /* See if we remembered the system loader */ |
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181 if ( loader==NULL && gdata->system_loader != 0 ) { |
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182 return gdata->system_loader; |
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183 } |
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184 if ( loader==NULL ) { |
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185 env = NULL; |
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186 } |
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187 index = search(env, loader); |
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188 if ( index == 0 ) { |
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189 static LoaderInfo empty_info; |
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190 LoaderInfo info; |
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191 |
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192 info = empty_info; |
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193 if ( loader != NULL ) { |
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194 HPROF_ASSERT(env!=NULL); |
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195 info.globalref = newWeakGlobalReference(env, loader); |
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196 info.object_index = 0; |
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197 } |
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198 index = table_create_entry(gdata->loader_table, NULL, 0, (void*)&info); |
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199 } |
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200 HPROF_ASSERT(search(env,loader)==index); |
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201 /* Remember the system loader */ |
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202 if ( loader==NULL && gdata->system_loader == 0 ) { |
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203 gdata->system_loader = index; |
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204 } |
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205 return index; |
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206 } |
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207 |
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208 void |
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209 loader_init(void) |
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210 { |
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211 gdata->loader_table = table_initialize("Loader", |
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212 16, 16, 0, (int)sizeof(LoaderInfo)); |
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213 } |
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214 |
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215 void |
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216 loader_list(void) |
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217 { |
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218 debug_message( |
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219 "--------------------- Loader Table ------------------------\n"); |
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220 table_walk_items(gdata->loader_table, &list_item, NULL); |
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221 debug_message( |
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222 "----------------------------------------------------------\n"); |
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223 } |
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224 |
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225 void |
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226 loader_cleanup(void) |
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227 { |
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228 table_cleanup(gdata->loader_table, &cleanup_item, NULL); |
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229 gdata->loader_table = NULL; |
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230 } |
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231 |
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232 void |
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233 loader_delete_global_references(JNIEnv *env) |
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234 { |
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235 table_walk_items(gdata->loader_table, &delete_ref_item, (void*)env); |
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236 } |
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237 |
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238 /* Get the object index for a class loader */ |
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239 ObjectIndex |
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240 loader_object_index(JNIEnv *env, LoaderIndex index) |
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241 { |
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242 LoaderInfo *info; |
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243 ObjectIndex object_index; |
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244 jobject wref; |
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245 |
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246 /* Assume no object index at first (default class loader) */ |
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247 info = get_info(index); |
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248 object_index = info->object_index; |
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249 wref = info->globalref; |
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250 if ( wref != NULL && object_index == 0 ) { |
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251 jobject lref; |
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252 |
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253 object_index = 0; |
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254 lref = newLocalReference(env, wref); |
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255 if ( lref != NULL && !isSameObject(env, lref, NULL) ) { |
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256 jlong tag; |
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257 |
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258 /* Get the tag on the object and extract the object_index */ |
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259 tag = getTag(lref); |
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260 if ( tag != (jlong)0 ) { |
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261 object_index = tag_extract(tag); |
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262 } |
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263 } |
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264 if ( lref != NULL ) { |
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265 deleteLocalReference(env, lref); |
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266 } |
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267 info->object_index = object_index; |
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268 } |
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269 return object_index; |
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270 } |
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