[Lldb-commits] [PATCH] D50327: Add ConstString::IsNull() to tell between null vs. empty strings and fix usage in Mangled::GetDemangledName()

[Stefan Gränitz via Phabricator via lldb-commits]

sgraenitz created this revision.
sgraenitz added reviewers: labath, jingham.
Herald added a subscriber: erik.pilkington.

`IsEmpty()` and `operator bool() == false` have equal semantics. Usage in Mangled::GetDemangledName() was incorrect. What it actually wants is a check for null-string. Split this off of https://reviews.llvm.org/D50071 and added a test to clarify usage.


https://reviews.llvm.org/D50327

Files:
  include/lldb/Utility/ConstString.h
  source/Core/Mangled.cpp
  unittests/Utility/ConstStringTest.cpp


Index: unittests/Utility/ConstStringTest.cpp
===================================================================
--- unittests/Utility/ConstStringTest.cpp
+++ unittests/Utility/ConstStringTest.cpp
@@ -33,3 +33,20 @@
   EXPECT_TRUE(foo.GetMangledCounterpart(counterpart));
   EXPECT_EQ("bar", counterpart.GetStringRef());
 }
+
+TEST(ConstStringTest, NullAndEmptyStates) {
+  ConstString foo("foo");
+  EXPECT_FALSE(!foo);
+  EXPECT_FALSE(foo.IsEmpty());
+  EXPECT_FALSE(foo.IsNull());
+
+  ConstString empty("");
+  EXPECT_TRUE(!empty);
+  EXPECT_TRUE(empty.IsEmpty());
+  EXPECT_FALSE(empty.IsNull());
+
+  ConstString null;
+  EXPECT_TRUE(!null);
+  EXPECT_TRUE(null.IsEmpty());
+  EXPECT_TRUE(null.IsNull());
+}
Index: source/Core/Mangled.cpp
===================================================================
--- source/Core/Mangled.cpp
+++ source/Core/Mangled.cpp
@@ -242,7 +242,7 @@
 Mangled::GetDemangledName(lldb::LanguageType language) const {
   // Check to make sure we have a valid mangled name and that we haven't
   // already decoded our mangled name.
-  if (m_mangled && !m_demangled) {
+  if (m_mangled && m_demangled.IsNull()) {
     // We need to generate and cache the demangled name.
     static Timer::Category func_cat(LLVM_PRETTY_FUNCTION);
     Timer scoped_timer(func_cat, "Mangled::GetDemangledName (m_mangled = %s)",
@@ -312,7 +312,7 @@
         free(demangled_name);
       }
     }
-    if (!m_demangled) {
+    if (m_demangled.IsNull()) {
       // Set the demangled string to the empty string to indicate we tried to
       // parse it once and failed.
       m_demangled.SetCString("");
Index: include/lldb/Utility/ConstString.h
===================================================================
--- include/lldb/Utility/ConstString.h
+++ include/lldb/Utility/ConstString.h
@@ -345,6 +345,15 @@
   //------------------------------------------------------------------
   bool IsEmpty() const { return m_string == nullptr || m_string[0] == '\0'; }
 
+  //------------------------------------------------------------------
+  /// Test for null string.
+  ///
+  /// @return
+  ///     @li \b true if there is no string associated with this instance.
+  ///     @li \b false if there is a string associated with this instance.
+  //------------------------------------------------------------------
+  bool IsNull() const { return m_string == nullptr; }
+
   //------------------------------------------------------------------
   /// Set the C string value.
   ///


-------------- next part --------------
A non-text attachment was scrubbed...
Name: D50327.159278.patch
Type: text/x-patch
Size: 2496 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/lldb-commits/attachments/20180806/ab2345ef/attachment-0001.bin>