Bug 1120796 - Part 2: Replace ConvertibleToBool hackarounds with explicit bool operators. r=Waldo

image/src/imgFrame.h

@@ -386,10 +386,6 @@ private: // data
  */
 class DrawableFrameRef MOZ_FINAL
 {
-  // Implementation details for safe boolean conversion.
-  typedef void (DrawableFrameRef::* ConvertibleToBool)(float*****, double*****);
-  void nonNull(float*****, double*****) {}
-
 public:
   DrawableFrameRef() { }
 
@@ -416,10 +412,7 @@ public:
     return *this;
   }
 
-  operator ConvertibleToBool() const
-  {
-    return bool(mFrame) ? &DrawableFrameRef::nonNull : 0;
-  }
+  explicit operator bool() const { return bool(mFrame); }
 
   imgFrame* operator->()
   {
@@ -461,10 +454,6 @@ private:
  */
 class RawAccessFrameRef MOZ_FINAL
 {
-  // Implementation details for safe boolean conversion.
-  typedef void (RawAccessFrameRef::* ConvertibleToBool)(float*****, double*****);
-  void nonNull(float*****, double*****) {}
-
 public:
   RawAccessFrameRef() { }
 
@@ -503,10 +492,7 @@ public:
     return *this;
   }
 
-  operator ConvertibleToBool() const
-  {
-    return bool(mFrame) ? &RawAccessFrameRef::nonNull : 0;
-  }
+  explicit operator bool() const { return bool(mFrame); }
 
   imgFrame* operator->()
   {

js/public/Debug.h

@@ -142,8 +142,6 @@ class Builder {
     class BuiltThing {
         friend class BuilderOrigin;
 
-        void nonNull() {}
-
       protected:
         // The Builder to which this trusted thing belongs.
         Builder &owner;
@@ -170,10 +168,9 @@ class Builder {
             return *this;
         }
 
-        typedef void (BuiltThing::* ConvertibleToBool)();
-        operator ConvertibleToBool() const {
-            // If we ever instantiate BuiltThink<Value>, this might not suffice.
-            return value ? &BuiltThing::nonNull : 0;
+        explicit operator bool() const {
+            // If we ever instantiate BuiltThing<Value>, this might not suffice.
+            return value;
         }
 
       private:
@@ -221,8 +218,7 @@ class Builder {
         bool defineProperty(JSContext *cx, const char *name, JS::HandleObject value);
         bool defineProperty(JSContext *cx, const char *name, Object &value);
 
-        using Base::ConvertibleToBool;
-        using Base::operator ConvertibleToBool;
+        using Base::operator bool;
     };
 
     // Build an empty object for direct use by debugger code, owned by this

js/public/HashTable.h

@@ -210,7 +210,7 @@ class HashMap
     /************************************************** Shorthand operations */
 
     bool has(const Lookup &l) const {
-        return impl.lookup(l) != nullptr;
+        return impl.lookup(l).found();
     }
 
     // Overwrite existing value with v. Return false on oom.
@@ -441,7 +441,7 @@ class HashSet
     /************************************************** Shorthand operations */
 
     bool has(const Lookup &l) const {
-        return impl.lookup(l) != nullptr;
+        return impl.lookup(l).found();
     }
 
     // Add |u| if it is not present already. Return false on oom.
@@ -767,8 +767,6 @@ class HashTable : private AllocPolicy
     class Ptr
     {
         friend class HashTable;
-        typedef void (Ptr::* ConvertibleToBool)();
-        void nonNull() {}
 
         Entry *entry_;
 #ifdef JS_DEBUG
@@ -800,8 +798,8 @@ class HashTable : private AllocPolicy
             return entry_->isLive();
         }
 
-        operator ConvertibleToBool() const {
-            return found() ? &Ptr::nonNull : 0;
+        explicit operator bool() const {
+            return found();
         }
 
         bool operator==(const Ptr &rhs) const {

js/public/HeapAPI.h

@@ -153,9 +153,6 @@ struct Zone
 // to several kinds of GC thing.
 class JS_FRIEND_API(GCCellPtr)
 {
-    typedef void (GCCellPtr::* ConvertibleToBool)();
-    void nonNull() {}
-
   public:
     // Construction from a void* and trace kind.
     GCCellPtr(void *gcthing, JSGCTraceKind traceKind) : ptr(checkedCast(gcthing, traceKind)) {}
@@ -179,9 +176,9 @@ class JS_FRIEND_API(GCCellPtr)
     }
 
     // Allow GCCellPtr to be used in a boolean context.
-    operator ConvertibleToBool() const {
+    explicit operator bool() const {
         MOZ_ASSERT(bool(asCell()) == (kind() != JSTRACE_NULL));
-        return asCell() ? &GCCellPtr::nonNull : 0;
+        return asCell();
     }
 
     // Simplify checks to the kind.

js/public/UbiNode.h

@@ -250,9 +250,6 @@ class Node {
         Concrete<T>::construct(base(), ptr);
     }
 
-    typedef void (Node::* ConvertibleToBool)();
-    void nonNull() {}
-
   public:
     Node() { construct<void>(nullptr); }
 
@@ -304,8 +301,8 @@ class Node {
     bool operator==(const Node &rhs) const { return *base() == *rhs.base(); }
     bool operator!=(const Node &rhs) const { return *base() != *rhs.base(); }
 
-    operator ConvertibleToBool() const {
-        return base()->ptr ? &Node::nonNull : 0;
+    explicit operator bool() const {
+        return base()->ptr != nullptr;
     }
 
     template<typename T>

js/src/ds/InlineMap.h

@@ -103,8 +103,6 @@ class InlineMap
         InlineElem  *inlPtr;
         bool        isInlinePtr;
 
-        typedef Ptr ******* ConvertibleToBool;
-
         explicit Ptr(WordMapPtr p) : mapPtr(p), isInlinePtr(false) {}
         explicit Ptr(InlineElem *ie) : inlPtr(ie), isInlinePtr(true) {}
         void operator==(const Ptr &other);
@@ -124,8 +122,8 @@ class InlineMap
             return isInlinePtr ? bool(inlPtr) : mapPtr.found();
         }
 
-        operator ConvertibleToBool() const {
-            return ConvertibleToBool(found());
+        explicit operator bool() const {
+            return found();
         }
 
         K &key() {
@@ -157,8 +155,6 @@ class InlineMap
 
         void operator==(const AddPtr &other);
 
-        typedef AddPtr ******* ConvertibleToBool;
-
       public:
         AddPtr() {}
 
@@ -166,8 +162,8 @@ class InlineMap
             return isInlinePtr ? inlPtrFound : mapAddPtr.found();
         }
 
-        operator ConvertibleToBool() const {
-            return found() ? ConvertibleToBool(1) : ConvertibleToBool(0);
+        explicit operator bool() const {
+            return found();
         }
 
         V &value() {

js/src/gc/GCInternals.h

@@ -74,11 +74,8 @@ class IncrementalSafety
     static IncrementalSafety Safe() { return IncrementalSafety(nullptr); }
     static IncrementalSafety Unsafe(const char *reason) { return IncrementalSafety(reason); }
 
-    typedef void (IncrementalSafety::* ConvertibleToBool)();
-    void nonNull() {}
-
-    operator ConvertibleToBool() const {
-        return reason_ == nullptr ? &IncrementalSafety::nonNull : 0;
+    explicit operator bool() const {
+        return reason_ == nullptr;
     }
 
     const char *reason() {

js/src/jshashutil.h

@@ -36,11 +36,9 @@ struct DependentAddPtr
         return table.relookupOrAdd(addPtr, key, value);
     }
 
-    typedef void (DependentAddPtr::* ConvertibleToBool)();
-    void nonNull() {}
 
     bool found() const                 { return addPtr.found(); }
-    operator ConvertibleToBool() const { return found() ? &DependentAddPtr::nonNull : 0; }
+    explicit operator bool() const     { return found(); }
     const Entry &operator*() const     { return *addPtr; }
     const Entry *operator->() const    { return &*addPtr; }
 

js/src/vm/ArrayBufferObject.h

@@ -171,9 +171,6 @@ class ArrayBufferObject : public ArrayBufferObjectMaybeShared
 
         friend class ArrayBufferObject;
 
-        typedef void (BufferContents::* ConvertibleToBool)();
-        void nonNull() {}
-
         BufferContents(uint8_t *data, BufferKind kind) : data_(data), kind_(kind) {
             MOZ_ASSERT((kind_ & ~KIND_MASK) == 0);
         }
@@ -194,7 +191,7 @@ class ArrayBufferObject : public ArrayBufferObjectMaybeShared
         uint8_t *data() const { return data_; }
         BufferKind kind() const { return kind_; }
 
-        operator ConvertibleToBool() const { return data_ ? &BufferContents::nonNull : nullptr; }
+        explicit operator bool() const { return data_ != nullptr; }
     };
 
     static const Class class_;

js/src/vm/Debugger.h

@@ -128,8 +128,8 @@ class DebuggerWeakMap : private WeakMap<PreBarriered<UnbarrieredKey>, Relocatabl
 
     bool hasKeyInZone(JS::Zone *zone) {
         CountMap::Ptr p = zoneCounts.lookup(zone);
-        MOZ_ASSERT_IF(p, p->value() > 0);
-        return p;
+        MOZ_ASSERT_IF(p.found(), p->value() > 0);
+        return p.found();
     }
 
   private:

js/src/vm/StructuredClone.cpp

@@ -904,7 +904,7 @@ JSStructuredCloneWriter::startObject(HandleObject obj, bool *backref)
 {
     /* Handle cycles in the object graph. */
     CloneMemory::AddPtr p = memory.lookupForAdd(obj);
-    if ((*backref = p))
+    if ((*backref = p.found()))
         return out.writePair(SCTAG_BACK_REFERENCE_OBJECT, p->value());
     if (!memory.add(p, obj, memory.count()))
         return false;

mfbt/Maybe.h

@@ -82,9 +82,6 @@ struct Nothing { };
 template<class T>
 class Maybe
 {
-  typedef void (Maybe::* ConvertibleToBool)(float*****, double*****);
-  void nonNull(float*****, double*****) {}
-
   bool mIsSome;
   AlignedStorage2<T> mStorage;
 
@@ -154,7 +151,7 @@ public:
   }
 
   /* Methods that check whether this Maybe contains a value */
-  operator ConvertibleToBool() const { return mIsSome ? &Maybe::nonNull : 0; }
+  explicit operator bool() const { return isSome(); }
   bool isSome() const { return mIsSome; }
   bool isNothing() const { return !mIsSome; }
 

mfbt/Range.h

@@ -20,9 +20,6 @@ class Range
   const RangedPtr<T> mStart;
   const RangedPtr<T> mEnd;
 
-  typedef void (Range::* ConvertibleToBool)();
-  void nonNull() {}
-
 public:
   Range() : mStart(nullptr, 0), mEnd(nullptr, 0) {}
   Range(T* aPtr, size_t aLength)
@@ -36,7 +33,7 @@ public:
 
   T& operator[](size_t aOffset) const { return mStart[aOffset]; }
 
-  operator ConvertibleToBool() const { return mStart ? &Range::nonNull : 0; }
+  explicit operator bool() const { return mStart != nullptr; }
 };
 
 } // namespace mozilla

mfbt/RangedPtr.h

@@ -49,9 +49,6 @@ class RangedPtr
   T* const mRangeEnd;
 #endif
 
-  typedef void (RangedPtr::* ConvertibleToBool)();
-  void nonNull() {}
-
   void checkSanity()
   {
     MOZ_ASSERT(mRangeStart <= mPtr);
@@ -118,7 +115,7 @@ public:
 
   T* get() const { return mPtr; }
 
-  operator ConvertibleToBool() const { return mPtr ? &RangedPtr::nonNull : 0; }
+  explicit operator bool() const { return mPtr != nullptr; }
 
   /*
    * You can only assign one RangedPtr into another if the two pointers have

mfbt/UniquePtr.h

@@ -286,21 +286,13 @@ public:
     return get();
   }
 
+  explicit operator bool() const { return get() != nullptr; }
+
   Pointer get() const { return ptr(); }
 
   DeleterType& getDeleter() { return del(); }
   const DeleterType& getDeleter() const { return del(); }
 
-private:
-  typedef void (UniquePtr::* ConvertibleToBool)(double, char);
-  void nonNull(double, char) {}
-
-public:
-  operator ConvertibleToBool() const
-  {
-    return get() != nullptr ? &UniquePtr::nonNull : nullptr;
-  }
-
   Pointer release()
   {
     Pointer p = ptr();
@@ -433,22 +425,14 @@ public:
     return *this;
   }
 
+  explicit operator bool() const { return get() != nullptr; }
+
   T& operator[](decltype(sizeof(int)) aIndex) const { return get()[aIndex]; }
   Pointer get() const { return mTuple.first(); }
 
   DeleterType& getDeleter() { return mTuple.second(); }
   const DeleterType& getDeleter() const { return mTuple.second(); }
 
-private:
-  typedef void (UniquePtr::* ConvertibleToBool)(double, char);
-  void nonNull(double, char) {}
-
-public:
-  operator ConvertibleToBool() const
-  {
-    return get() != nullptr ? &UniquePtr::nonNull : nullptr;
-  }
-
   Pointer release()
   {
     Pointer p = mTuple.first();