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1 /* |
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2 * Copyright (c) 2007 Nokia Corporation and/or its subsidiary(-ies). |
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3 * All rights reserved. |
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4 * This component and the accompanying materials are made available |
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5 * under the terms of "Eclipse Public License v1.0" |
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6 * which accompanies this distribution, and is available |
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7 * at the URL "http://www.eclipse.org/legal/epl-v10.html". |
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8 * |
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9 * Initial Contributors: |
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10 * Nokia Corporation - initial contribution. |
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11 * |
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12 * Contributors: |
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13 * |
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14 * Description: |
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15 * |
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16 * Parser for function return values |
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17 * |
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18 */ |
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19 package com.nokia.tracecompiler.source; |
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20 |
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21 import java.util.Collections; |
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22 import java.util.List; |
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23 |
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24 /** |
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25 * Parser for function return values |
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26 * |
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27 */ |
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28 class FunctionReturnValueParser { |
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29 |
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30 /** |
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31 * Source parser |
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32 */ |
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33 private SourceParser parser; |
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34 |
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35 /** |
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36 * Comparator for source return values |
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37 */ |
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38 private PositionArrayComparator comparator = new PositionArrayComparator(); |
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39 |
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40 /** |
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41 * Macros representing return statement |
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42 */ |
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43 private List<String> returnExtensions; |
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44 |
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45 /** |
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46 * Constructor |
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47 * |
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48 * @param parser |
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49 * the source parser |
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50 */ |
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51 FunctionReturnValueParser(SourceParser parser) { |
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52 this.parser = parser; |
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53 } |
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54 |
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55 /** |
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56 * Parses the return values of given source context |
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57 * |
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58 * @param context |
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59 * the context to be parsed |
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60 * @param list |
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61 * the list of return values |
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62 */ |
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63 void parseReturnValues(SourceContext context, List<SourceReturn> list) { |
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64 String statement = SourceConstants.RETURN; |
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65 try { |
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66 parseReturnValues(context, list, statement); |
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67 } catch (SourceParserException e) { |
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68 } |
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69 if (returnExtensions != null && returnExtensions.size() > 0) { |
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70 for (int i = 0; i < returnExtensions.size(); i++) { |
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71 try { |
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72 parseReturnValues(context, list, returnExtensions.get(i)); |
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73 } catch (SourceParserException e) { |
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74 } |
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75 } |
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76 Collections.sort(list, comparator); |
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77 } |
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78 if (context.isVoid()) { |
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79 boolean addToEnd = true; |
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80 // If there were no return statements, the trace is added to end |
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81 // Otherwise the last return statement needs to be checked. If it is |
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82 // at the end of the function, the return trace is not added to |
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83 // the end |
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84 if (!list.isEmpty()) { |
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85 SourceReturn ret = list.get(list.size() - 1); |
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86 SourceIterator itr = parser.createIterator(ret.getOffset() |
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87 + ret.getLength() + 1, SourceParser.SKIP_ALL); |
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88 try { |
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89 itr.next(); |
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90 // If the next character after return statement is the end |
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91 // of function, the return is not added |
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92 if (itr.currentIndex() == context.getOffset() |
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93 + context.getLength() - 1) { |
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94 addToEnd = false; |
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95 } |
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96 } catch (SourceParserException e) { |
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97 addToEnd = false; |
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98 } |
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99 } |
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100 if (addToEnd) { |
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101 list.add(new SourceReturn(parser, context.getOffset() |
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102 + context.getLength() - 1, 0)); |
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103 } |
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104 } |
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105 } |
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106 |
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107 /** |
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108 * Parses the return values of given source context that use the given |
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109 * return statement |
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110 * |
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111 * @param context |
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112 * the context to be parsed |
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113 * @param list |
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114 * the list of return values |
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115 * @param statement |
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116 * the return statement |
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117 * @throws SourceParserException |
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118 * if processing fails |
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119 */ |
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120 private void parseReturnValues(SourceContext context, |
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121 List<SourceReturn> list, String statement) |
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122 throws SourceParserException { |
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123 FunctionReturnValueSearchData data = new FunctionReturnValueSearchData(); |
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124 int offset = context.getOffset(); |
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125 int end = offset + context.getLength(); |
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126 SourceSearch search = parser.startStringSearch(statement, offset, end, |
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127 SourceParser.MATCH_WHOLE_WORD | SourceParser.SKIP_ALL); |
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128 boolean looping = true; |
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129 do { |
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130 data.index = search.findNext(); |
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131 if (data.index != -1) { |
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132 data.itr = parser.createIterator(data.index |
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133 + statement.length(), SourceParser.SKIP_ALL); |
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134 locateReturnStatement(data); |
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135 if (data.endOffset != -1 && data.startOffset != -1) { |
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136 SourceReturn ret = createReturnStatement(data); |
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137 list.add(ret); |
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138 } else { |
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139 // End of return statement missing |
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140 looping = false; |
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141 } |
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142 } else { |
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143 looping = false; |
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144 } |
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145 } while (looping); |
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146 } |
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147 |
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148 /** |
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149 * Locates the start and end offsets for the return statement |
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150 * |
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151 * @param data |
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152 * the search data |
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153 * @throws SourceParserException |
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154 * if parser fails |
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155 */ |
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156 private void locateReturnStatement(FunctionReturnValueSearchData data) |
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157 throws SourceParserException { |
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158 data.startOffset = -1; |
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159 data.endOffset = -1; |
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160 boolean found = false; |
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161 boolean colonAllowed = false; |
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162 while (data.itr.hasNext() && !found) { |
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163 char c = data.itr.next(); |
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164 if (c == ';') { |
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165 data.endOffset = data.itr.previousIndex() + 1; |
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166 found = true; |
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167 } else if (c == '}') { |
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168 found = true; |
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169 } else if (c == '?') { |
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170 colonAllowed = true; |
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171 } else if (c == ':') { |
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172 if (data.itr.hasNext() && data.itr.peek() == ':') { |
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173 // Skips over :: |
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174 c = data.itr.next(); |
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175 } else { |
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176 if (colonAllowed) { |
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177 colonAllowed = false; |
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178 } else { |
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179 data.endOffset = data.itr.previousIndex() + 1; |
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180 found = true; |
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181 } |
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182 } |
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183 } |
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184 if (data.startOffset == -1) { |
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185 data.startOffset = data.itr.currentIndex(); |
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186 } |
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187 } |
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188 } |
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189 |
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190 /** |
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191 * Creates a return statement |
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192 * |
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193 * @param data |
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194 * the parser data |
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195 * @return the new statement |
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196 * @throws SourceParserException |
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197 * if parser fails |
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198 */ |
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199 private SourceReturn createReturnStatement( |
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200 FunctionReturnValueSearchData data) throws SourceParserException { |
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201 SourceReturn ret = new SourceReturn(parser, data.startOffset, |
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202 data.endOffset - data.startOffset); |
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203 if (checkTag(data.startOffset, data.endOffset - data.startOffset)) { |
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204 ret.setTagHazard(); |
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205 } |
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206 if (checkPreviousChar(data.index - 1)) { |
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207 ret.setPreviousCharHazard(); |
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208 } |
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209 return ret; |
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210 } |
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211 |
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212 /** |
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213 * Checks if the tag is hazardous |
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214 * |
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215 * @param start |
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216 * start offset |
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217 * @param length |
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218 * tag length |
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219 * @return true if there is a problem |
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220 */ |
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221 private boolean checkTag(int start, int length) { |
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222 boolean hazard = false; |
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223 boolean previous = false; |
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224 // Function calls and increment / decrement operators are not safe |
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225 for (int i = start; i < start + length && !hazard; i++) { |
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226 char c = parser.getData(i); |
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227 if (c == '(') { |
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228 // If return statement is within brackets, it is not hazardous |
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229 if (i != start || parser.getData(start + length - 1) != ')') { |
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230 hazard = true; |
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231 } |
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232 } else if (c == '?') { |
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233 hazard = true; |
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234 } else if (c == '-' || c == '+') { |
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235 if (previous) { |
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236 hazard = true; |
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237 } else { |
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238 previous = true; |
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239 } |
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240 } else { |
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241 previous = false; |
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242 } |
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243 } |
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244 return hazard; |
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245 } |
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246 |
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247 /** |
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248 * Checks if previous character is hazardous |
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249 * |
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250 * @param index |
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251 * the index |
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252 * @return true if hazard, false if not |
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253 * @throws SourceParserException |
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254 * if processing fails |
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255 */ |
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256 private boolean checkPreviousChar(int index) throws SourceParserException { |
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257 boolean hazard = false; |
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258 SourceIterator previtr = parser.createIterator(index, |
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259 SourceParser.SKIP_ALL | SourceParser.BACKWARD_SEARCH); |
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260 char prevchar = previtr.next(); |
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261 if (prevchar != ';' && prevchar != '{' && prevchar != '}') { |
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262 hazard = true; |
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263 } |
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264 return hazard; |
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265 } |
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266 |
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267 /** |
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268 * Finds the last return statement from the given context |
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269 * |
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270 * @param context |
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271 * the context |
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272 * @return the index to beginning of the return statement |
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273 */ |
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274 int findLast(SourceContext context) { |
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275 String statement = SourceConstants.RETURN; |
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276 int retval = findLast(context, statement); |
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277 if (returnExtensions != null && returnExtensions.size() > 0) { |
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278 int res; |
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279 for (int i = 0; i < returnExtensions.size(); i++) { |
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280 res = findLast(context, returnExtensions.get(i)); |
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281 if (res > retval) { |
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282 retval = res; |
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283 } |
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284 } |
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285 } |
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286 if (retval == -1) { |
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287 retval = context.getOffset() + context.getLength(); |
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288 } |
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289 return retval; |
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290 } |
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291 |
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292 /** |
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293 * Finds the last return statement from the given context |
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294 * |
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295 * @param context |
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296 * the context |
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297 * @param statement |
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298 * the statement to be searched |
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299 * @return the index to beginning of the return statement |
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300 */ |
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301 private int findLast(SourceContext context, String statement) { |
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302 // TODO: Backwards string search |
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303 int start = context.getOffset(); |
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304 int end = start + context.getLength(); |
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305 SourceSearch search = parser.startStringSearch(statement, start, end, |
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306 SourceParser.MATCH_WHOLE_WORD | SourceParser.SKIP_ALL); |
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307 int index = 0; |
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308 int retval = -1; |
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309 do { |
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310 index = search.findNext(); |
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311 if (index != -1) { |
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312 retval = index; |
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313 } |
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314 } while (index != -1); |
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315 return retval; |
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316 } |
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317 } |