Serialize and deserialize null (#783)

* Build (grpc's) nanopb with -DPB_FIELD_16BIT

We require (at least) 16 bit fields. (By default, nanopb uses 8 bit
fields, ie allowing up to 256 field tags.)

Also note that this patch adds this to grpc's nanopb, rather than to our
nanopb. We'll need to eventually either:
a) we instruct grpc to use our nanopb
b) we rely on grpc's nanopb instead of using our own.

(^ marked as a TODO for now.)

* Add some dependant protos

Imported from protobuf. Nanopb requires these to be present (though
anything using libprotobuf does not, as these are already built into
that.)

* Add generated nanopb protos based off of newly added proto definitions

* Build the nanopb protos

* Serialize and deserialize null

1 files changed, 45 insertions, 0 deletions

diff --git a/Firestore/Protos/CMakeLists.txt b/Firestore/Protos/CMakeLists.txt
new file mode 100644
index 0000000..f20f702
--- /dev/null
+++ b/Firestore/Protos/CMakeLists.txt
@@ -0,0 +1,45 @@
+cc_library(
+  firebase_firestore_protos_nanopb
+  SOURCES
+    nanopb/firestore/local/maybe_document.pb.c
+    nanopb/firestore/local/maybe_document.pb.h
+    nanopb/firestore/local/mutation.pb.c
+    nanopb/firestore/local/mutation.pb.h
+    nanopb/firestore/local/target.pb.c
+    nanopb/firestore/local/target.pb.h
+    nanopb/google/api/annotations.pb.c
+    nanopb/google/api/annotations.pb.h
+    nanopb/google/api/http.pb.c
+    nanopb/google/api/http.pb.h
+    nanopb/google/firestore/v1beta1/common.pb.c
+    nanopb/google/firestore/v1beta1/common.pb.h
+    nanopb/google/firestore/v1beta1/document.pb.c
+    nanopb/google/firestore/v1beta1/document.pb.h
+    nanopb/google/firestore/v1beta1/firestore.pb.c
+    nanopb/google/firestore/v1beta1/firestore.pb.h
+    nanopb/google/firestore/v1beta1/query.pb.c
+    nanopb/google/firestore/v1beta1/query.pb.h
+    nanopb/google/firestore/v1beta1/write.pb.c
+    nanopb/google/firestore/v1beta1/write.pb.h
+    nanopb/google/protobuf/any.pb.c
+    nanopb/google/protobuf/any.pb.h
+    nanopb/google/protobuf/empty.pb.c
+    nanopb/google/protobuf/empty.pb.h
+    nanopb/google/protobuf/struct.pb.c
+    nanopb/google/protobuf/struct.pb.h
+    nanopb/google/protobuf/timestamp.pb.c
+    nanopb/google/protobuf/timestamp.pb.h
+    nanopb/google/protobuf/wrappers.pb.c
+    nanopb/google/protobuf/wrappers.pb.h
+    nanopb/google/rpc/status.pb.c
+    nanopb/google/rpc/status.pb.h
+    nanopb/google/type/latlng.pb.c
+    nanopb/google/type/latlng.pb.h
+  DEPENDS
+    nanopb
+)
+
+target_compile_definitions(
+  firebase_firestore_protos_nanopb PUBLIC
+    -DPB_FIELD_16BIT
+)