Merge pull request #2856 from esbena/js/fix-RegExp-getPredecessor-getSuccessor

semmle-qlci · web-flow · commit 091c6c063cf7 · 2020-02-20T09:50:52.000Z
Approved by max-schaefer
diff --git a/javascript/ql/src/semmle/javascript/Regexp.qll b/javascript/ql/src/semmle/javascript/Regexp.qll
@@ -75,25 +75,22 @@ class RegExpTerm extends Locatable, @regexpterm {
 
   /** Gets the regular expression term that is matched (textually) before this one, if any. */
   RegExpTerm getPredecessor() {
-    exists(RegExpSequence seq, int i |
-      seq.getChild(i) = this and
-      seq.getChild(i - 1) = result
+    exists(RegExpTerm parent | parent = getParent() |
+      result = parent.(RegExpSequence).previousElement(this)
+      or
+      not exists(parent.(RegExpSequence).previousElement(this)) and
+      not parent instanceof RegExpSubPattern and
+      result = parent.getPredecessor()
     )
-    or
-    result = getParent().(RegExpTerm).getPredecessor()
   }
 
   /** Gets the regular expression term that is matched (textually) after this one, if any. */
   RegExpTerm getSuccessor() {
-    exists(RegExpSequence seq, int i |
-      seq.getChild(i) = this and
-      seq.getChild(i + 1) = result
-    )
-    or
-    exists(RegExpTerm parent |
-      parent = getParent() and
-      not parent instanceof RegExpSubPattern
-    |
+    exists(RegExpTerm parent | parent = getParent() |
+      result = parent.(RegExpSequence).nextElement(this)
+      or
+      not exists(parent.(RegExpSequence).nextElement(this)) and
+      not parent instanceof RegExpSubPattern and
       result = parent.getSuccessor()
     )
   }
@@ -313,6 +310,19 @@ class RegExpSequence extends RegExpTerm, @regexp_seq {
     or
     result = getChild(i).getConstantValue() + getConstantValue(i+1)
   }
+
+    /** Gets the element preceding `element` in this sequence. */
+  RegExpTerm previousElement(RegExpTerm element) {
+    element = nextElement(result)
+  }
+
+  /** Gets the element following `element` in this sequence. */
+  RegExpTerm nextElement(RegExpTerm element) {
+    exists(int i |
+      element = this.getChild(i) and
+      result = this.getChild(i + 1)
+    )
+  }
 }
 
 /**
diff --git a/javascript/ql/test/library-tests/RegExp/predecessors_and_successors/getPredecessor.expected b/javascript/ql/test/library-tests/RegExp/predecessors_and_successors/getPredecessor.expected
@@ -0,0 +1,38 @@
+| tst.js:2:2:2:2 | a | tst.js:2:3:2:5 | (b) |
+| tst.js:2:2:2:2 | a | tst.js:2:4:2:4 | b |
+| tst.js:3:2:3:3 | ab | tst.js:3:4:3:6 | (c) |
+| tst.js:3:2:3:3 | ab | tst.js:3:5:3:5 | c |
+| tst.js:4:2:4:2 | a | tst.js:4:3:4:6 | (bc) |
+| tst.js:4:2:4:2 | a | tst.js:4:4:4:5 | bc |
+| tst.js:5:2:5:2 | a | tst.js:5:3:5:8 | (b[c]) |
+| tst.js:5:2:5:2 | a | tst.js:5:4:5:4 | b |
+| tst.js:5:2:5:2 | a | tst.js:5:4:5:7 | b[c] |
+| tst.js:5:4:5:4 | b | tst.js:5:5:5:7 | [c] |
+| tst.js:5:4:5:4 | b | tst.js:5:6:5:6 | c |
+| tst.js:6:2:6:2 | a | tst.js:6:3:6:9 | (b\|[b]) |
+| tst.js:6:2:6:2 | a | tst.js:6:4:6:4 | b |
+| tst.js:6:2:6:2 | a | tst.js:6:4:6:8 | b\|[b] |
+| tst.js:6:2:6:2 | a | tst.js:6:6:6:8 | [b] |
+| tst.js:6:2:6:2 | a | tst.js:6:7:6:7 | b |
+| tst.js:7:2:7:2 | a | tst.js:7:3:7:10 | ([b][c]) |
+| tst.js:7:2:7:2 | a | tst.js:7:4:7:6 | [b] |
+| tst.js:7:2:7:2 | a | tst.js:7:4:7:9 | [b][c] |
+| tst.js:7:2:7:2 | a | tst.js:7:5:7:5 | b |
+| tst.js:7:4:7:6 | [b] | tst.js:7:7:7:9 | [c] |
+| tst.js:7:4:7:6 | [b] | tst.js:7:8:7:8 | c |
+| tst.js:8:2:8:2 | a | tst.js:8:3:8:13 | (b\|[b]\|[b]) |
+| tst.js:8:2:8:2 | a | tst.js:8:4:8:4 | b |
+| tst.js:8:2:8:2 | a | tst.js:8:4:8:12 | b\|[b]\|[b] |
+| tst.js:8:2:8:2 | a | tst.js:8:6:8:8 | [b] |
+| tst.js:8:2:8:2 | a | tst.js:8:7:8:7 | b |
+| tst.js:8:2:8:2 | a | tst.js:8:10:8:12 | [b] |
+| tst.js:8:2:8:2 | a | tst.js:8:11:8:11 | b |
+| tst.js:11:2:11:4 | (a) | tst.js:11:5:11:5 | b |
+| tst.js:12:2:12:4 | (a) | tst.js:12:5:12:6 | bc |
+| tst.js:13:2:13:5 | (ab) | tst.js:13:6:13:6 | c |
+| tst.js:14:2:14:7 | ([a]b) | tst.js:14:8:14:8 | c |
+| tst.js:14:3:14:5 | [a] | tst.js:14:6:14:6 | b |
+| tst.js:16:2:16:9 | ([a][b]) | tst.js:16:10:16:10 | c |
+| tst.js:16:3:16:5 | [a] | tst.js:16:6:16:8 | [b] |
+| tst.js:16:3:16:5 | [a] | tst.js:16:7:16:7 | b |
+| tst.js:17:2:17:12 | ([a]\|[a]\|a) | tst.js:17:13:17:13 | b |
diff --git a/javascript/ql/test/library-tests/RegExp/predecessors_and_successors/getPredecessor.ql b/javascript/ql/test/library-tests/RegExp/predecessors_and_successors/getPredecessor.ql
@@ -0,0 +1,5 @@
+import javascript
+
+from RegExpTerm pred, RegExpTerm succ
+where pred = succ.getPredecessor()
+select pred, succ
diff --git a/javascript/ql/test/library-tests/RegExp/predecessors_and_successors/getSuccessor.expected b/javascript/ql/test/library-tests/RegExp/predecessors_and_successors/getSuccessor.expected
@@ -0,0 +1,34 @@
+| tst.js:2:2:2:2 | a | tst.js:2:3:2:5 | (b) |
+| tst.js:3:2:3:3 | ab | tst.js:3:4:3:6 | (c) |
+| tst.js:4:2:4:2 | a | tst.js:4:3:4:6 | (bc) |
+| tst.js:5:2:5:2 | a | tst.js:5:3:5:8 | (b[c]) |
+| tst.js:5:4:5:4 | b | tst.js:5:5:5:7 | [c] |
+| tst.js:6:2:6:2 | a | tst.js:6:3:6:9 | (b\|[b]) |
+| tst.js:7:2:7:2 | a | tst.js:7:3:7:10 | ([b][c]) |
+| tst.js:7:4:7:6 | [b] | tst.js:7:7:7:9 | [c] |
+| tst.js:7:5:7:5 | b | tst.js:7:7:7:9 | [c] |
+| tst.js:8:2:8:2 | a | tst.js:8:3:8:13 | (b\|[b]\|[b]) |
+| tst.js:11:2:11:4 | (a) | tst.js:11:5:11:5 | b |
+| tst.js:11:3:11:3 | a | tst.js:11:5:11:5 | b |
+| tst.js:12:2:12:4 | (a) | tst.js:12:5:12:6 | bc |
+| tst.js:12:3:12:3 | a | tst.js:12:5:12:6 | bc |
+| tst.js:13:2:13:5 | (ab) | tst.js:13:6:13:6 | c |
+| tst.js:13:3:13:4 | ab | tst.js:13:6:13:6 | c |
+| tst.js:14:2:14:7 | ([a]b) | tst.js:14:8:14:8 | c |
+| tst.js:14:3:14:5 | [a] | tst.js:14:6:14:6 | b |
+| tst.js:14:3:14:6 | [a]b | tst.js:14:8:14:8 | c |
+| tst.js:14:4:14:4 | a | tst.js:14:6:14:6 | b |
+| tst.js:14:6:14:6 | b | tst.js:14:8:14:8 | c |
+| tst.js:16:2:16:9 | ([a][b]) | tst.js:16:10:16:10 | c |
+| tst.js:16:3:16:5 | [a] | tst.js:16:6:16:8 | [b] |
+| tst.js:16:3:16:8 | [a][b] | tst.js:16:10:16:10 | c |
+| tst.js:16:4:16:4 | a | tst.js:16:6:16:8 | [b] |
+| tst.js:16:6:16:8 | [b] | tst.js:16:10:16:10 | c |
+| tst.js:16:7:16:7 | b | tst.js:16:10:16:10 | c |
+| tst.js:17:2:17:12 | ([a]\|[a]\|a) | tst.js:17:13:17:13 | b |
+| tst.js:17:3:17:5 | [a] | tst.js:17:13:17:13 | b |
+| tst.js:17:3:17:11 | [a]\|[a]\|a | tst.js:17:13:17:13 | b |
+| tst.js:17:4:17:4 | a | tst.js:17:13:17:13 | b |
+| tst.js:17:7:17:9 | [a] | tst.js:17:13:17:13 | b |
+| tst.js:17:8:17:8 | a | tst.js:17:13:17:13 | b |
+| tst.js:17:11:17:11 | a | tst.js:17:13:17:13 | b |
diff --git a/javascript/ql/test/library-tests/RegExp/predecessors_and_successors/getSuccessor.ql b/javascript/ql/test/library-tests/RegExp/predecessors_and_successors/getSuccessor.ql
@@ -0,0 +1,5 @@
+import javascript
+
+from RegExpTerm pred, RegExpTerm succ
+where succ = pred.getSuccessor()
+select pred, succ
diff --git a/javascript/ql/test/library-tests/RegExp/predecessors_and_successors/tst.js b/javascript/ql/test/library-tests/RegExp/predecessors_and_successors/tst.js
@@ -0,0 +1,17 @@
+/ab/;
+/a(b)/;
+/ab(c)/;
+/a(bc)/;
+/a(b[c])/;
+/a(b|[b])/;
+/a([b][c])/;
+/a(b|[b]|[b])/;
+
+/ab/;
+/(a)b/;
+/(a)bc/;
+/(ab)c/;
+/([a]b)c/;
+/([a]|a)|b/;
+/([a][b])c/;
+/([a]|[a]|a)b/;
