Bug 1200642 - Add checkSimulatedOOM() to AllocPolicy r=Waldo

js/src/ds/LifoAlloc.h

@@ -559,6 +559,9 @@ class LifoAllocPolicy
     }
     void reportAllocOverflow() const {
     }
+    bool checkSimulatedOOM() const {
+        return fb == Infallible || !js::oom::ShouldFailWithOOM();
+    }
 };
 
 } // namespace js

js/src/jit/JitAllocPolicy.h

@@ -103,6 +103,9 @@ class JitAllocPolicy
     }
     void reportAllocOverflow() const {
     }
+    bool checkSimulatedOOM() const {
+        return !js::oom::ShouldFailWithOOM();
+    }
 };
 
 class OldJitAllocPolicy
@@ -120,6 +123,9 @@ class OldJitAllocPolicy
     }
     void reportAllocOverflow() const {
     }
+    bool checkSimulatedOOM() const {
+        return !js::oom::ShouldFailWithOOM();
+    }
 };
 
 class AutoJitContextAlloc

js/src/jsalloc.h

@@ -38,8 +38,14 @@ class SystemAllocPolicy
     }
     void free_(void* p) { js_free(p); }
     void reportAllocOverflow() const {}
+    bool checkSimulatedOOM() const {
+        return !js::oom::ShouldFailWithOOM();
+    }
 };
 
+class ExclusiveContext;
+void ReportOutOfMemory(ExclusiveContext* cxArg);
+
 /*
  * Allocation policy that calls the system memory functions and reports errors
  * to the context. Since the JSContext given on construction is stored for
@@ -93,6 +99,15 @@ class TempAllocPolicy
     }
 
     JS_FRIEND_API(void) reportAllocOverflow() const;
+
+    bool checkSimulatedOOM() const {
+        if (js::oom::ShouldFailWithOOM()) {
+            js::ReportOutOfMemory(reinterpret_cast<ExclusiveContext*>(cx_));
+            return false;
+        }
+
+        return true;
+    }
 };
 
 } /* namespace js */

js/src/vm/Runtime.h

@@ -2087,6 +2087,10 @@ class RuntimeAllocPolicy
 
     void free_(void* p) { js_free(p); }
     void reportAllocOverflow() const {}
+
+    bool checkSimulatedOOM() const {
+        return !js::oom::ShouldFailWithOOM();
+    }
 };
 
 extern const JSSecurityCallbacks NullSecurityCallbacks;

layout/style/nsNthIndexCache.h

@@ -70,6 +70,7 @@ private:
     void *realloc_(void *p, size_t bytes) { return ::realloc(p, bytes); }
     void free_(void *p) { ::free(p); }
     void reportAllocOverflow() const {}
+    bool checkSimulatedOOM() const { return true; }
   };
 
   typedef js::HashMap<nsIContent*, CacheEntry, js::DefaultHasher<nsIContent*>,

memory/replace/dmd/DMD.cpp

@@ -225,6 +225,7 @@ public:
   }
 
   static void reportAllocOverflow() { ExitOnFailure(nullptr); }
+  bool checkSimulatedOOM() const { return true; }
 };
 
 // This is only needed because of the |const void*| vs |void*| arg mismatch.

mfbt/AllocPolicy.h

@@ -39,6 +39,18 @@ namespace mozilla {
  *      to allocate more than the available memory space -- think allocating an
  *      array of large-size objects, where N * size overflows) before null is
  *      returned.
+ *  - bool checkSimulatedOOM() const
+ *      Some clients generally allocate memory yet in some circumstances won't
+ *      need to do so. For example, appending to a vector with a small amount of
+ *      inline storage generally allocates memory, but no allocation occurs
+ *      unless appending exceeds inline storage. But for testing purposes, it
+ *      can be useful to treat *every* operation as allocating.
+ *      Clients (such as this hypothetical append method implementation) should
+ *      call this method in situations that don't allocate, but could generally,
+ *      to support this. The default behavior should return true; more
+ *      complicated behavior might be to return false only after a certain
+ *      number of allocations-or-check-simulated-OOMs (coordinating with the
+ *      other AllocPolicy methods) have occurred.
  *
  * mfbt provides (and typically uses by default) only MallocAllocPolicy, which
  * does nothing more than delegate to the malloc/alloc/free functions.
@@ -83,6 +95,11 @@ public:
   void reportAllocOverflow() const
   {
   }
+
+  bool checkSimulatedOOM() const
+  {
+    return true;
+  }
 };
 
 } // namespace mozilla