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1   /***
2    * BSD-style license; for more info see http://pmd.sourceforge.net/license.html
3    */
4   package net.sourceforge.pmd.rules.strings;
5   
6   import net.sourceforge.pmd.AbstractRule;
7   import net.sourceforge.pmd.ast.ASTAdditiveExpression;
8   import net.sourceforge.pmd.ast.ASTBlockStatement;
9   import net.sourceforge.pmd.ast.ASTFieldDeclaration;
10  import net.sourceforge.pmd.ast.ASTFormalParameter;
11  import net.sourceforge.pmd.ast.ASTIfStatement;
12  import net.sourceforge.pmd.ast.ASTLiteral;
13  import net.sourceforge.pmd.ast.ASTName;
14  import net.sourceforge.pmd.ast.ASTPrimaryExpression;
15  import net.sourceforge.pmd.ast.ASTPrimaryPrefix;
16  import net.sourceforge.pmd.ast.ASTPrimarySuffix;
17  import net.sourceforge.pmd.ast.ASTSwitchLabel;
18  import net.sourceforge.pmd.ast.ASTSwitchStatement;
19  import net.sourceforge.pmd.ast.ASTVariableDeclaratorId;
20  import net.sourceforge.pmd.ast.Node;
21  import net.sourceforge.pmd.ast.SimpleNode;
22  import net.sourceforge.pmd.symboltable.NameOccurrence;
23  
24  import java.util.HashMap;
25  import java.util.HashSet;
26  import java.util.Iterator;
27  import java.util.List;
28  import java.util.Map;
29  import java.util.Set;
30  
31  /***
32   * This rule finds StringBuffers which may have been pre-sized incorrectly
33   * 
34   * See http://sourceforge.net/forum/forum.php?thread_id=1438119&forum_id=188194
35   * @author Allan Caplan
36   */
37  public class InsufficientStringBufferDeclaration extends AbstractRule {
38  
39      private final static Set blockParents;
40  
41      static {
42          blockParents = new HashSet();
43          blockParents.add(ASTIfStatement.class);
44          blockParents.add(ASTSwitchStatement.class);
45      }
46  
47      public Object visit(ASTVariableDeclaratorId node, Object data) {
48  
49          if (!"StringBuffer".equals(node.getNameDeclaration().getTypeImage())) {
50              return data;
51          }
52          Node rootNode = node;
53          int anticipatedLength = 0;
54          int constructorLength = 16;
55  
56          constructorLength = getConstructorLength(node, constructorLength);
57          anticipatedLength = getInitialLength(node);
58          List usage = node.getUsages();
59          Map blocks = new HashMap();
60          for (int ix = 0; ix < usage.size(); ix++) {
61              NameOccurrence no = (NameOccurrence) usage.get(ix);
62              SimpleNode n = no.getLocation();
63              if (!InefficientStringBuffering.isInStringBufferOperation(n, 3, "append")) {
64  
65                  if (!no.isOnLeftHandSide() && !InefficientStringBuffering.isInStringBufferOperation(n, 3, "setLength")) {
66                      continue;
67                  }
68                  if (constructorLength != -1 && anticipatedLength > constructorLength) {
69                      anticipatedLength += processBlocks(blocks);
70                      String[] param = { String.valueOf(constructorLength), String.valueOf(anticipatedLength) };
71                      addViolation(data, rootNode, param);
72                  }
73                  constructorLength = getConstructorLength(n, constructorLength);
74                  rootNode = n;
75                  anticipatedLength = getInitialLength(node);
76              }
77              ASTPrimaryExpression s = (ASTPrimaryExpression) n.getFirstParentOfType(ASTPrimaryExpression.class);
78              int numChildren = s.jjtGetNumChildren();
79              for (int jx = 0; jx < numChildren; jx++) {
80                  SimpleNode sn = (SimpleNode) s.jjtGetChild(jx);
81                  if (!(sn instanceof ASTPrimarySuffix) || sn.getImage() != null) {
82                      continue;
83                  }
84                  int thisSize = 0;
85                  Node block = getFirstParentBlock(sn);
86                  if (isAdditive(sn)) {
87                      thisSize = processAdditive(sn);
88                  } else {
89                      thisSize = processNode(sn);
90                  }
91                  if (block != null) {
92                      storeBlockStatistics(blocks, thisSize, block);
93                  } else {
94                      anticipatedLength += thisSize;
95                  }
96              }
97          }
98          anticipatedLength += processBlocks(blocks);
99          if (constructorLength != -1 && anticipatedLength > constructorLength) {
100             String[] param = { String.valueOf(constructorLength), String.valueOf(anticipatedLength) };
101             addViolation(data, rootNode, param);
102         }
103         return data;
104     }
105 
106     /***
107      * This rule is concerned with IF and Switch blocks. Process the block into
108      * a local Map, from which we can later determine which is the longest block
109      * inside
110      * 
111      * @param blocks
112      *            The map of blocks in the method being investigated
113      * @param thisSize
114      *            The size of the current block
115      * @param block
116      *            The block in question
117      */
118     private void storeBlockStatistics(Map blocks, int thisSize, Node block) {
119         Node statement = block.jjtGetParent();
120         if (ASTIfStatement.class.equals(block.jjtGetParent().getClass())) {
121             // Else Ifs are their own subnode in AST. So we have to
122             // look a little farther up the tree to find the IF statement
123             Node possibleStatement = ((SimpleNode) statement).getFirstParentOfType(ASTIfStatement.class);
124             while(possibleStatement != null && possibleStatement.getClass().equals(ASTIfStatement.class)) {
125                 statement = possibleStatement;
126                 possibleStatement = ((SimpleNode) possibleStatement).getFirstParentOfType(ASTIfStatement.class);
127             }
128         }
129         Map thisBranch = (Map) blocks.get(statement);
130         if (thisBranch == null) {
131             thisBranch = new HashMap();
132             blocks.put(statement, thisBranch);
133         }
134         Integer x = (Integer) thisBranch.get(block);
135         if (x != null) {
136             thisSize += x.intValue();
137         }
138         thisBranch.put(statement, new Integer(thisSize));
139     }
140 
141     private int processBlocks(Map blocks) {
142         int anticipatedLength = 0;
143         int ifLength = 0;
144         for (Iterator iter = blocks.entrySet().iterator(); iter.hasNext();) {
145             Map.Entry entry = (Map.Entry) iter.next();
146             ifLength = 0;
147             for (Iterator iter2 = ((Map) entry.getValue()).entrySet().iterator(); iter2.hasNext();) {
148                 Map.Entry entry2 = (Map.Entry) iter2.next();
149                 Integer value = (Integer) entry2.getValue();
150                 ifLength = Math.max(ifLength, value.intValue());
151             }
152             anticipatedLength += ifLength;
153         }
154         return anticipatedLength;
155     }
156 
157     private int processAdditive(SimpleNode sn) {
158         ASTAdditiveExpression additive = (ASTAdditiveExpression) sn.getFirstChildOfType(ASTAdditiveExpression.class);
159         if (additive == null) {
160             return 0;
161         }
162         int anticipatedLength = 0;
163         for (int ix = 0; ix < additive.jjtGetNumChildren(); ix++) {
164             SimpleNode childNode = (SimpleNode) additive.jjtGetChild(ix);
165             ASTLiteral literal = (ASTLiteral) childNode.getFirstChildOfType(ASTLiteral.class);
166             if (literal != null && literal.getImage() != null) {
167                 anticipatedLength += literal.getImage().length() - 2;
168             }
169         }
170 
171         return anticipatedLength;
172     }
173 
174     private static final boolean isLiteral(String str) {
175         if (str.length() == 0) {
176             return false;
177         }
178         char c = str.charAt(0);
179         return (c == '"' || c == '\'');
180     }
181 
182     private int processNode(SimpleNode sn) {
183         int anticipatedLength = 0;
184         ASTPrimaryPrefix xn = (ASTPrimaryPrefix) sn.getFirstChildOfType(ASTPrimaryPrefix.class);
185         if (xn.jjtGetNumChildren() != 0 && xn.jjtGetChild(0).getClass().equals(ASTLiteral.class)) {
186             String str = ((SimpleNode) xn.jjtGetChild(0)).getImage();
187             if(isLiteral(str)){
188                 anticipatedLength += str.length() - 2;
189             } else if(str.startsWith("0x")){
190                 anticipatedLength += 1;
191             } else {
192                 anticipatedLength += str.length();
193             }            
194         }
195         return anticipatedLength;
196     }
197 
198     private int getConstructorLength(SimpleNode node, int constructorLength) {
199         int iConstructorLength = constructorLength;
200         SimpleNode block = (SimpleNode) node.getFirstParentOfType(ASTBlockStatement.class);
201         List literal;
202 
203         if (block == null) {
204             block = (ASTFieldDeclaration) node.getFirstParentOfType(ASTFieldDeclaration.class);
205         }
206         if (block == null) {
207             block = (ASTFormalParameter) node.getFirstParentOfType(ASTFormalParameter.class);
208             if (block != null) {
209                 iConstructorLength = -1;
210             }
211         }
212         literal = (block.findChildrenOfType(ASTLiteral.class));
213         if (literal.isEmpty()) {
214             List name = (block.findChildrenOfType(ASTName.class));
215             if (!name.isEmpty()) {
216                 iConstructorLength = -1;
217             }
218         } else if (literal.size() == 1) {
219             String str = ((SimpleNode) literal.get(0)).getImage();
220             if (str == null) {
221                 iConstructorLength = 0;
222             } else if (isLiteral(str)) {
223                 // since it's not taken into account
224                 // anywhere. only count the extra 16
225                 // characters
226                 iConstructorLength = 14 + str.length(); // don't add the constructor's length,
227             } else {
228                 iConstructorLength = Integer.parseInt(str);
229             }
230         } else {
231             iConstructorLength = -1;
232         }
233         
234         if(iConstructorLength == 0){
235             iConstructorLength = 16;
236         }
237 
238         return iConstructorLength;
239     }
240 
241 
242     private int getInitialLength(SimpleNode node) {
243         SimpleNode block = (SimpleNode) node.getFirstParentOfType(ASTBlockStatement.class);
244         List literal;
245 
246         if (block == null) {
247             block = (ASTFieldDeclaration) node.getFirstParentOfType(ASTFieldDeclaration.class);
248             if (block == null) {
249                 block = (ASTFormalParameter) node.getFirstParentOfType(ASTFormalParameter.class);
250             }
251         }
252         literal = (block.findChildrenOfType(ASTLiteral.class));
253         if (literal.size() == 1) {
254             String str = ((SimpleNode) literal.get(0)).getImage();
255             if (str != null && isLiteral(str)) {
256                 return str.length() - 2; // take off the quotes
257             }
258         }
259         
260         return 0;
261     }
262 
263     private boolean isAdditive(SimpleNode n) {
264         return n.findChildrenOfType(ASTAdditiveExpression.class).size() >= 1;
265     }
266 
267     /***
268      * Locate the block that the given node is in, if any
269      * 
270      * @param node
271      *            The node we're looking for a parent of
272      * @return Node - The node that corresponds to any block that may be a
273      *         parent of this object
274      */
275     private Node getFirstParentBlock(Node node) {
276         Node parentNode = node.jjtGetParent();
277 
278         Node lastNode = node;
279         while (parentNode != null && !blockParents.contains(parentNode.getClass())) {
280             lastNode = parentNode;
281             parentNode = parentNode.jjtGetParent();
282         }
283         if (parentNode != null && ASTIfStatement.class.equals(parentNode.getClass())) {
284             parentNode = lastNode;
285         } else if (parentNode != null && parentNode.getClass().equals(ASTSwitchStatement.class)) {
286             parentNode = getSwitchParent(parentNode, lastNode);
287         }
288         return parentNode;
289     }
290 
291     /***
292      * Determine which SwitchLabel we belong to inside a switch
293      * 
294      * @param parentNode
295      *            The parent node we're looking at
296      * @param lastNode
297      *            The last node processed
298      * @return The parent node for the switch statement
299      */
300     private static Node getSwitchParent(Node parentNode, Node lastNode) {
301         int allChildren = parentNode.jjtGetNumChildren();
302         ASTSwitchLabel label = null;
303         for (int ix = 0; ix < allChildren; ix++) {
304             Node n = parentNode.jjtGetChild(ix);
305             if (n.getClass().equals(ASTSwitchLabel.class)) {
306                 label = (ASTSwitchLabel) n;
307             } else if (n.equals(lastNode)) {
308                 parentNode = label;
309                 break;
310             }
311         }
312         return parentNode;
313     }
314 
315 }