[PATCH] D19876: Add an AST matcher for string-literal length

[Etienne Bergeron via cfe-commits]

etienneb created this revision.
etienneb added reviewers: alexfh, sbenza, aaron.ballman, klimek.
etienneb added a subscriber: cfe-commits.
Herald added a subscriber: klimek.

This patch is adding support for a matcher to check string literal length.

This matcher is used in clang-tidy checkers and is part of this refactoring:
  see: http://reviews.llvm.org/D19841

http://reviews.llvm.org/D19876

Files:
  docs/LibASTMatchersReference.html
  include/clang/ASTMatchers/ASTMatchers.h
  lib/ASTMatchers/Dynamic/Registry.cpp
  unittests/ASTMatchers/ASTMatchersTest.cpp


Index: unittests/ASTMatchers/ASTMatchersTest.cpp
===================================================================
--- unittests/ASTMatchers/ASTMatchersTest.cpp
+++ unittests/ASTMatchers/ASTMatchersTest.cpp
@@ -2536,6 +2536,17 @@
   EXPECT_TRUE(notMatches("const char s[1] = {'a'};", Literal));
 }
 
+TEST(StringLiteral, LengthIs) {
+  StatementMatcher Literal = stringLiteral(lengthIs(4));
+  EXPECT_TRUE(matches("const char *s = \"abcd\";", Literal));
+  // wide string
+  EXPECT_TRUE(matches("const wchar_t *s = L\"abcd\";", Literal));
+  // with escaped characters
+  EXPECT_TRUE(matches("const char *s = \"\x05\x06\x07\x08\";", Literal));
+  // no matching, too small
+  EXPECT_TRUE(notMatches("const char *s = \"ab\";", Literal));
+}
+
 TEST(Matcher, CharacterLiterals) {
   StatementMatcher CharLiteral = characterLiteral();
   EXPECT_TRUE(matches("const char c = 'c';", CharLiteral));
Index: lib/ASTMatchers/Dynamic/Registry.cpp
===================================================================
--- lib/ASTMatchers/Dynamic/Registry.cpp
+++ lib/ASTMatchers/Dynamic/Registry.cpp
@@ -323,6 +323,7 @@
   REGISTER_MATCHER(labelDecl);
   REGISTER_MATCHER(labelStmt);
   REGISTER_MATCHER(lambdaExpr);
+  REGISTER_MATCHER(lengthIs);
   REGISTER_MATCHER(lValueReferenceType);
   REGISTER_MATCHER(matchesName);
   REGISTER_MATCHER(matchesSelector);
Index: include/clang/ASTMatchers/ASTMatchers.h
===================================================================
--- include/clang/ASTMatchers/ASTMatchers.h
+++ include/clang/ASTMatchers/ASTMatchers.h
@@ -1560,12 +1560,23 @@
 ///
 /// Example matches "abcd", L"abcd"
 /// \code
-///   char *s = "abcd"; wchar_t *ws = L"abcd"
+///   char *s = "abcd"; wchar_t *ws = L"abcd";
 /// \endcode
 const internal::VariadicDynCastAllOfMatcher<
   Stmt,
   StringLiteral> stringLiteral;
 
+/// \brief Matches string length for a given string literal node.
+///
+/// Example matches "abcd", L"abcd"
+/// \code
+///   char *s = "abcd"; wchar_t *ws = L"abcd";
+///   char *t = "a";
+/// \endcode
+AST_MATCHER_P(StringLiteral, lengthIs, unsigned, N) {
+  return Node.getLength() == N;
+}
+
 /// \brief Matches character literals (also matches wchar_t).
 ///
 /// Not matching Hex-encoded chars (e.g. 0x1234, which is a IntegerLiteral),
Index: docs/LibASTMatchersReference.html
===================================================================
--- docs/LibASTMatchersReference.html
+++ docs/LibASTMatchersReference.html
@@ -410,7 +410,7 @@
 
 Given
   typedef int X;
-   using Y = int;
+  using Y = int;
 typeAliasDecl()
   matches "using Y = int", but not "typedef int X"
 </pre></td></tr>
@@ -421,7 +421,7 @@
 
 Given
   typedef int X;
-   using Y = int;
+  using Y = int;
 typedefDecl()
   matches "typedef int X", but not "using Y = int"
 </pre></td></tr>
@@ -432,7 +432,7 @@
 
 Given
   typedef int X;
-   using Y = int;
+  using Y = int;
 typedefNameDecl()
   matches "typedef int X" and "using Y = int"
 </pre></td></tr>
@@ -1217,7 +1217,7 @@
 <tr><td colspan="4" class="doc" id="stringLiteral0"><pre>Matches string literals (also matches wide string literals).
 
 Example matches "abcd", L"abcd"
-  char *s = "abcd"; wchar_t *ws = L"abcd"
+  char *s = "abcd"; wchar_t *ws = L"abcd";
 </pre></td></tr>
 
 
@@ -2941,6 +2941,15 @@
 </pre></td></tr>
 
 
+<tr><td>Matcher&lt;<a href="http://clang.llvm.org/doxygen/classclang_1_1StringLiteral.html";>StringLiteral</a>&gt;</td><td class="name" onclick="toggle('lengthIs0')"><a name="lengthIs0Anchor">lengthIs</a></td><td>unsigned N</td></tr>
+<tr><td colspan="4" class="doc" id="lengthIs0"><pre>Matches string length for a given string literal node.
+
+Example matches "abcd", L"abcd"
+  char *s = "abcd"; wchar_t *ws = L"abcd";
+  char *t = "a";
+</pre></td></tr>
+
+
 <tr><td>Matcher&lt;<a href="http://clang.llvm.org/doxygen/classclang_1_1TagDecl.html";>TagDecl</a>&gt;</td><td class="name" onclick="toggle('isDefinition0')"><a name="isDefinition0Anchor">isDefinition</a></td><td></td></tr>
 <tr><td colspan="4" class="doc" id="isDefinition0"><pre>Matches if a declaration has a body attached.
 

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