third_party/protobuf: Update to HEAD (83d681ee2c)

third_party/protobuf/objectivec/GPBBootstrap.h

Index: third_party/protobuf/objectivec/GPBBootstrap.h
diff --git a/third_party/protobuf/objectivec/GPBBootstrap.h b/third_party/protobuf/objectivec/GPBBootstrap.h
index ffefa7706cef88daaf6099cb0a7418124f15c2de..ed53ae7cbc0363231b5ea8699e7e4b8ce47e49cc 100644
--- a/third_party/protobuf/objectivec/GPBBootstrap.h
+++ b/third_party/protobuf/objectivec/GPBBootstrap.h
@@ -28,11 +28,13 @@
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
-// The Objective C runtime has complete enough info that most protos don’t end
-// up using this, so leaving it on is no cost or very little cost.  If you
-// happen to see it causing bloat, this is the way to disable it. If you do
-// need to disable it, try only disabling it for Release builds as having
-// full TextFormat can be useful for debugging.
+/**
+ * The Objective C runtime has complete enough info that most protos don’t end
+ * up using this, so leaving it on is no cost or very little cost.  If you
+ * happen to see it causing bloat, this is the way to disable it. If you do
+ * need to disable it, try only disabling it for Release builds as having
+ * full TextFormat can be useful for debugging.
+ **/
 #ifndef GPBOBJC_SKIP_MESSAGE_TEXTFORMAT_EXTRAS
 #define GPBOBJC_SKIP_MESSAGE_TEXTFORMAT_EXTRAS 0
 #endif
@@ -42,30 +44,45 @@
 #if !__has_feature(objc_fixed_enum)
  #error All supported Xcode versions should support objc_fixed_enum.
 #endif
+
 // If the headers are imported into Objective-C++, we can run into an issue
 // where the defintion of NS_ENUM (really CF_ENUM) changes based on the C++
 // standard that is in effect.  If it isn't C++11 or higher, the definition
 // doesn't allow us to forward declare. We work around this one case by
 // providing a local definition. The default case has to use NS_ENUM for the
 // magic that is Swift bridging of enums.
-#if (__cplusplus && __cplusplus < 201103L)
+#if (defined(__cplusplus) && __cplusplus && __cplusplus < 201103L)
  #define GPB_ENUM(X) enum X : int32_t X; enum X : int32_t
 #else
  #define GPB_ENUM(X) NS_ENUM(int32_t, X)
 #endif
-// GPB_ENUM_FWD_DECLARE is used for forward declaring enums, ex:
-//   GPB_ENUM_FWD_DECLARE(Foo_Enum)
-//   @property (nonatomic) Foo_Enum value;
+
+/**
+ * GPB_ENUM_FWD_DECLARE is used for forward declaring enums, for example:
+ *
+ * ```
+ * GPB_ENUM_FWD_DECLARE(Foo_Enum)
+ *
+ * @interface BarClass : NSObject
+ * @property (nonatomic) enum Foo_Enum value;
+ * - (void)bazMethod:(enum Foo_Enum):value;
+ * @end
+ * ```
+ **/
 #define GPB_ENUM_FWD_DECLARE(X) enum X : int32_t
 
-// Based upon CF_INLINE. Forces inlining in release.
+/**
+ * Based upon CF_INLINE. Forces inlining in non DEBUG builds.
+ **/
 #if !defined(DEBUG)
 #define GPB_INLINE static __inline__ __attribute__((always_inline))
 #else
 #define GPB_INLINE static __inline__
 #endif
 
-// For use in public headers that might need to deal with ARC.
+/**
+ * For use in public headers that might need to deal with ARC.
+ **/
 #ifndef GPB_UNSAFE_UNRETAINED
 #if __has_feature(objc_arc)
 #define GPB_UNSAFE_UNRETAINED __unsafe_unretained
@@ -76,10 +93,31 @@
 
 // If property name starts with init we need to annotate it to get past ARC.
 // http://stackoverflow.com/questions/18723226/how-do-i-annotate-an-objective-c-property-with-an-objc-method-family/18723227#18723227
+//
+// Meant to be used internally by generated code.
 #define GPB_METHOD_FAMILY_NONE __attribute__((objc_method_family(none)))
 
-// The protoc-gen-objc version which works with the current version of the
-// generated Objective C sources.  In general we don't want to change the
-// runtime interfaces (or this version) as it means everything has to be
-// regenerated.
+// ----------------------------------------------------------------------------
+// These version numbers are all internal to the ObjC Protobuf runtime; they
+// are used to ensure compatibility between the generated sources and the
+// headers being compiled against and/or the version of sources being run
+// against.
+//
+// They are all #defines so the values are captured into every .o file they
+// are used in and to allow comparisons in the preprocessor.
+
+// Current library runtime version.
+// - Gets bumped when the runtime makes changes to the interfaces between the
+//   generated code and runtime (things added/removed, etc).
+#define GOOGLE_PROTOBUF_OBJC_VERSION 30002
+
+// Minimum runtime version supported for compiling/running against.
+// - Gets changed when support for the older generated code is dropped.
+#define GOOGLE_PROTOBUF_OBJC_MIN_SUPPORTED_VERSION 30001
+
+
+// This is a legacy constant now frozen in time for old generated code. If
+// GOOGLE_PROTOBUF_OBJC_MIN_SUPPORTED_VERSION ever gets moved above 30001 then
+// this should also change to break code compiled with an old runtime that
+// can't be supported any more.
 #define GOOGLE_PROTOBUF_OBJC_GEN_VERSION 30001