4 files changed, 40 insertions, 2 deletions
diff --git a/objectivec/GPBCodedInputStream.h b/objectivec/GPBCodedInputStream.h
index de27b186..fbe5009c 100644
--- a/objectivec/GPBCodedInputStream.h
+++ b/objectivec/GPBCodedInputStream.h
@@ -218,6 +218,27 @@ CF_EXTERN_C_END
 - (size_t)position;
 
 /**
+ * Moves the limit to the given byte offset starting at the current location.
+ *
+ * @exception GPBCodedInputStreamException If the requested bytes exceeed the
+ *            current limit.
+ *
+ * @param byteLimit The number of bytes to move the limit, offset to the current
+ *                  location.
+ *
+ * @return The limit offset before moving the new limit.
+ */
+- (size_t)pushLimit:(size_t)byteLimit;
+
+/**
+ * Moves the limit back to the offset as it was before calling pushLimit:.
+ *
+ * @param oldLimit The number of bytes to move the current limit. Usually this
+ *                 is the value returned by the pushLimit: method.
+ */
+- (void)popLimit:(size_t)oldLimit;
+
+/**
  * Verifies that the last call to -readTag returned the given tag value. This
  * is used to verify that a nested group ended with the correct end tag.
  *
diff --git a/objectivec/GPBCodedInputStream.m b/objectivec/GPBCodedInputStream.m
index 2b578dd5..e8c8989c 100644
--- a/objectivec/GPBCodedInputStream.m
+++ b/objectivec/GPBCodedInputStream.m
@@ -400,6 +400,14 @@ void GPBCodedInputStreamCheckLastTagWas(GPBCodedInputStreamState *state,
   return state_.bufferPos;
 }
 
+- (size_t)pushLimit:(size_t)byteLimit {
+  return GPBCodedInputStreamPushLimit(&state_, byteLimit);
+}
+
+- (void)popLimit:(size_t)oldLimit {
+  GPBCodedInputStreamPopLimit(&state_, oldLimit);
+}
+
 - (double)readDouble {
   return GPBCodedInputStreamReadDouble(&state_);
 }
diff --git a/objectivec/GPBMessage.h b/objectivec/GPBMessage.h
index 0cb74f9f..c07ec888 100644
--- a/objectivec/GPBMessage.h
+++ b/objectivec/GPBMessage.h
@@ -65,9 +65,18 @@ CF_EXTERN_C_END
 
 /**
  * Base class that each generated message subclasses from.
+ *
+ * @note While the class support NSSecureCoding, if the message has any
+ *       extensions, they will end up reloaded in @c unknownFields as there is
+ *       no way for the @c NSCoding plumbing to pass through a
+ *       @c GPBExtensionRegistry. To support extensions, instead of passing the
+ *       calls off to the Message, simple store the result of @c data, and then
+ *       when loading, fetch the data and use
+ *       @c +parseFromData:extensionRegistry:error: to provide an extension
+ *       registry.
  **/
 @interface GPBMessage : NSObject<NSSecureCoding, NSCopying>
- 
+
 // If you add an instance method/property to this class that may conflict with
 // fields declared in protos, you need to update objective_helpers.cc. The main
 // cases are methods that take no arguments, or setFoo:/hasFoo: type methods.
diff --git a/objectivec/README.md b/objectivec/README.md
index 06118349..7226f0b9 100644
--- a/objectivec/README.md
+++ b/objectivec/README.md
@@ -44,7 +44,7 @@ Add `objectivec/\*.h` & `objectivec/\*.m` except for
 If the target is using ARC, remember to turn off ARC (`-fno-objc-arc`) for the
 `.m` files.
 
-The files generated by `protoc` for the `*.proto` files (`\*.pbobjc.h' and
+The files generated by `protoc` for the `*.proto` files (`\*.pbobjc.h` and
 `\*.pbobjc.m`) are then also added to the target.
 
 Usage