16 files changed, 522 insertions, 40 deletions
diff --git a/CMakeLists.txt b/CMakeLists.txt
index edcd611..f58a980 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -37,7 +37,7 @@ set(FIREBASE_INSTALL_DIR ${PROJECT_BINARY_DIR})
 enable_testing()
 
 include(external/FirebaseCore)
-
 include(external/googletest)
 include(external/leveldb)
+include(external/grpc)
 include(external/firestore)
diff --git a/Firestore/CMakeLists.txt b/Firestore/CMakeLists.txt
index 9b90815..4e009e0 100644
--- a/Firestore/CMakeLists.txt
+++ b/Firestore/CMakeLists.txt
@@ -13,9 +13,9 @@
 # limitations under the License.
 
 cmake_minimum_required(VERSION 2.8.11)
-project(firestore)
+project(firestore C CXX)
 
-set(FIREBASE_SOURCE_DIR "${CMAKE_CURRENT_LIST_DIR}/..")
+set(FIREBASE_SOURCE_DIR ${CMAKE_CURRENT_LIST_DIR}/..)
 
 # CMAKE_INSTALL_PREFIX should be passed in to this build so that it can find
 # outputs of the superbuild. This is handled automatically if run via the
@@ -23,13 +23,14 @@ set(FIREBASE_SOURCE_DIR "${CMAKE_CURRENT_LIST_DIR}/..")
 #
 # If you want to use this project directly in e.g. CLion, make sure you
 # configure this.
-set(FIREBASE_INSTALL_DIR "${CMAKE_INSTALL_PREFIX}")
+set(FIREBASE_INSTALL_DIR ${CMAKE_INSTALL_PREFIX})
 
 list(INSERT CMAKE_MODULE_PATH 0 ${FIREBASE_SOURCE_DIR}/cmake)
 include(utils)
 
 find_package(GTest REQUIRED)
 find_package(LevelDB REQUIRED)
+find_package(GRPC REQUIRED)
 
 if(APPLE)
   find_package(FirebaseCore REQUIRED)
@@ -41,7 +42,7 @@ set(CMAKE_CXX_STANDARD_REQUIRED ON)
 set(CMAKE_CXX_EXTENSIONS OFF)
 
 # Fully qualified imports, project wide
-include_directories("${FIREBASE_SOURCE_DIR}")
+include_directories(${FIREBASE_SOURCE_DIR})
 
 if(APPLE)
   # CMake has no special support for Objective-C as a distinct language but enabling modules and
@@ -57,5 +58,5 @@ if(APPLE)
 endif(APPLE)
 
 enable_testing()
-add_subdirectory(third_party/abseil-cpp EXCLUDE_FROM_ALL)
+add_subdirectory(third_party/abseil-cpp)
 add_subdirectory(core)
diff --git a/Firestore/core/CMakeLists.txt b/Firestore/core/CMakeLists.txt
index c49b6db..9291fbd 100644
--- a/Firestore/core/CMakeLists.txt
+++ b/Firestore/core/CMakeLists.txt
@@ -13,4 +13,7 @@
 # limitations under the License.
 
 add_subdirectory(src/firebase/firestore/util)
+add_subdirectory(src/firebase/firestore/remote)
+
 add_subdirectory(test/firebase/firestore/util)
+add_subdirectory(test/firebase/firestore/remote)
diff --git a/Firestore/core/src/firebase/firestore/remote/CMakeLists.txt b/Firestore/core/src/firebase/firestore/remote/CMakeLists.txt
new file mode 100644
index 0000000..74ad80b
--- /dev/null
+++ b/Firestore/core/src/firebase/firestore/remote/CMakeLists.txt
@@ -0,0 +1,23 @@
+# Copyright 2018 Google
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+add_library(
+  firebase_firestore_remote
+  datastore.h
+  datastore.cc
+)
+target_link_libraries(
+  firebase_firestore_remote
+  grpc::grpc
+)
diff --git a/Firestore/core/src/firebase/firestore/remote/datastore.cc b/Firestore/core/src/firebase/firestore/remote/datastore.cc
new file mode 100644
index 0000000..f8a8988
--- /dev/null
+++ b/Firestore/core/src/firebase/firestore/remote/datastore.cc
@@ -0,0 +1,31 @@
+/*
+ * Copyright 2018 Google
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "Firestore/core/src/firebase/firestore/remote/datastore.h"
+
+namespace firebase {
+namespace firestore {
+namespace remote {
+
+Datastore::Datastore() {
+}
+
+Datastore::~Datastore() {
+}
+
+}  // namespace remote
+}  // namespace firestore
+}  // namespace firebase
diff --git a/Firestore/core/src/firebase/firestore/remote/datastore.h b/Firestore/core/src/firebase/firestore/remote/datastore.h
new file mode 100644
index 0000000..807b75f
--- /dev/null
+++ b/Firestore/core/src/firebase/firestore/remote/datastore.h
@@ -0,0 +1,40 @@
+/*
+ * Copyright 2018 Google
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef FIRESTORE_CORE_SRC_FIREBASE_FIRESTORE_REMOTE_DATASTORE_H_
+#define FIRESTORE_CORE_SRC_FIREBASE_FIRESTORE_REMOTE_DATASTORE_H_
+
+namespace firebase {
+namespace firestore {
+namespace remote {
+
+class Datastore {
+ public:
+  Datastore();
+  ~Datastore();
+
+  Datastore(const Datastore& other) = delete;
+  Datastore(Datastore&& other) = delete;
+
+  Datastore& operator=(const Datastore& other) = delete;
+  Datastore& operator=(Datastore&& other) = delete;
+};
+
+}  // namespace remote
+}  // namespace firestore
+}  // namespace firebase
+
+#endif  // FIRESTORE_CORE_SRC_FIREBASE_FIRESTORE_REMOTE_DATASTORE_H_
diff --git a/Firestore/core/test/firebase/firestore/remote/CMakeLists.txt b/Firestore/core/test/firebase/firestore/remote/CMakeLists.txt
new file mode 100644
index 0000000..f0731c3
--- /dev/null
+++ b/Firestore/core/test/firebase/firestore/remote/CMakeLists.txt
@@ -0,0 +1,22 @@
+# Copyright 2018 Google
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+cc_test(
+  firebase_firestore_remote_test
+  datastore_test.cc
+)
+target_link_libraries(
+  firebase_firestore_remote_test
+  firebase_firestore_remote
+)
diff --git a/Firestore/core/test/firebase/firestore/remote/datastore_test.cc b/Firestore/core/test/firebase/firestore/remote/datastore_test.cc
new file mode 100644
index 0000000..46a19cc
--- /dev/null
+++ b/Firestore/core/test/firebase/firestore/remote/datastore_test.cc
@@ -0,0 +1,28 @@
+/*
+ * Copyright 2018 Google
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "Firestore/core/src/firebase/firestore/remote/datastore.h"
+
+#include <grpc/grpc.h>
+#include <gtest/gtest.h>
+
+TEST(Datastore, CanLinkToGrpc) {
+  // This test doesn't actually do anything interesting as far as actually
+  // using gRPC is concerned but that it can run at all is proof that all the
+  // libraries required for gRPC to work are actually linked correctly into the
+  // test.
+  grpc_init();
+}
diff --git a/cmake/ExternalProjectFlags.cmake b/cmake/ExternalProjectFlags.cmake
new file mode 100644
index 0000000..ed4db2c
--- /dev/null
+++ b/cmake/ExternalProjectFlags.cmake
@@ -0,0 +1,71 @@
+# Copyright 2018 Google
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+include(CMakeParseArguments)
+
+# Assemble the git-related arguments to an external project making use of the
+# latest features where available but avoiding them when run under CMake
+# versions that don't support them.
+#
+# The complete set of git-related arguments are stored as a list in the
+# variable named by RESULT_VAR in the calling scope.
+#
+# Currently this handles:
+#   * GIT_SUBMODULES -- added on CMake 3.0 or later. Earlier CMakes will
+#       check out all submodules.
+#   * GIT_SHALLOW -- added by default on CMake 3.6 or later. Disable by passing
+#       GIT_SHALLOW OFF
+#   * GIT_PROGRESS -- added by default on CMake 3.8 or later. Disable by
+#       passing GIT_PROGRESS OFF
+function(ExternalProject_GitSource RESULT_VAR)
+  # Parse arguments
+  set(options "")
+  set(single_value GIT_REPOSITORY GIT_TAG GIT_PROGRESS GIT_SHALLOW)
+  set(multi_value GIT_SUBMODULES)
+  cmake_parse_arguments(EP "${options}" "${single_value}" "${multi_value}" ${ARGN})
+
+  set(
+    result
+    GIT_REPOSITORY ${EP_GIT_REPOSITORY}
+    GIT_TAG ${EP_GIT_TAG}
+    ${EP_UNPARSED_ARGUMENTS}
+  )
+
+  # CMake 3.0 added support for constraining the set of submodules to clone
+  if(NOT (CMAKE_VERSION VERSION_LESS "3.0") AND EP_GIT_SUBMODULES)
+    list(APPEND result GIT_SUBMODULES ${EP_GIT_SUBMODULES})
+  endif()
+
+  # CMake 3.6 added support for shallow git clones. Use a shallow clone if
+  # available
+  if(NOT (CMAKE_VERSION VERSION_LESS "3.6"))
+    if(NOT EP_GIT_SHALLOW)
+      set(EP_GIT_SHALLOW ON)
+    endif()
+
+    list(APPEND result GIT_SHALLOW ${EP_GIT_SHALLOW})
+  endif()
+
+  # CMake 3.8 added support for showing progress for large downloads
+  if(NOT (CMAKE_VERSION VERSION_LESS "3.8"))
+    if(NOT EP_GIT_PROGRESS)
+      set(EP_GIT_PROGRESS ON)
+    endif()
+
+    list(APPEND result GIT_PROGRESS ${EP_GIT_PROGRESS})
+  endif()
+
+  set(${RESULT_VAR} ${result} PARENT_SCOPE)
+
+endfunction()
diff --git a/cmake/FindGRPC.cmake b/cmake/FindGRPC.cmake
new file mode 100644
index 0000000..f594b9e
--- /dev/null
+++ b/cmake/FindGRPC.cmake
@@ -0,0 +1,142 @@
+# Copyright 2018 Google
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+include(FindPackageHandleStandardArgs)
+include(FindZLIB)
+
+set(BINARY_DIR ${FIREBASE_INSTALL_DIR}/external/grpc)
+
+## ZLIB
+
+# the grpc ExternalProject already figures out if zlib should be built or
+# referenced from its installed location. If it elected to allow grpc to build
+# zlib then it will be available at this location.
+find_library(
+  ZLIB_LIBRARY
+  NAMES z
+  HINTS ${BINARY_DIR}/src/grpc-build/third_party/zlib
+)
+
+# If found above, the standard package will honor the ZLIB_LIBRARY variable.
+find_package(ZLIB REQUIRED)
+
+
+## BoringSSL/OpenSSL
+
+find_path(
+  OPENSSL_INCLUDE_DIR openssl/ssl.h
+  HINTS ${BINARY_DIR}/src/grpc/third_party/boringssl/include
+)
+
+find_library(
+  OPENSSL_SSL_LIBRARY
+  NAMES ssl
+  HINTS ${BINARY_DIR}/src/grpc-build/third_party/boringssl/ssl
+)
+
+find_library(
+  OPENSSL_CRYPTO_LIBRARY
+  NAMES crypto
+  HINTS ${BINARY_DIR}/src/grpc-build/third_party/boringssl/crypto
+)
+
+find_package(OpenSSL REQUIRED)
+
+
+## C-Ares
+
+find_library(
+  CARES_LIBRARY
+  NAMES cares
+  HINTS ${BINARY_DIR}/src/grpc-build/third_party/cares/cares/lib
+)
+if(NOT (CARES_LIBRARY STREQUAL "CARES_LIBRARY-NOTFOUND"))
+  if (NOT TARGET c-ares::ares)
+    add_library(c-ares::ares UNKNOWN IMPORTED)
+    set_target_properties(
+      c-ares::ares PROPERTIES
+      IMPORTED_LOCATION ${CARES_LIBRARY}
+    )
+  endif()
+endif()
+
+
+## GRPC
+
+find_path(
+  GRPC_INCLUDE_DIR grpc/grpc.h
+  HINTS
+    $ENV{GRPC_ROOT}/include
+    ${GRPC_ROOT}/include
+    ${BINARY_DIR}/src/grpc/include
+)
+
+find_library(
+  GPR_LIBRARY
+  NAMES gpr
+  HINTS
+    $ENV{GRPC_ROOT}/lib
+    ${GRPC_ROOT}/lib
+    ${BINARY_DIR}/src/grpc-build
+)
+
+find_library(
+  GRPC_LIBRARY
+  NAMES grpc
+  HINTS
+    $ENV{GRPC_ROOT}/lib
+    ${GRPC_ROOT}/lib
+    ${BINARY_DIR}/src/grpc-build
+)
+
+find_package_handle_standard_args(
+  gRPC
+  DEFAULT_MSG
+  GRPC_INCLUDE_DIR
+  GRPC_LIBRARY
+  GPR_LIBRARY
+)
+
+if(GRPC_FOUND)
+  set(GRPC_INCLUDE_DIRS ${GRPC_INCLUDE_DIR})
+  set(GRPC_LIBRARIES ${GRPC_LIBRARY})
+
+  if (NOT TARGET grpc::gpr)
+    add_library(grpc::gpr UNKNOWN IMPORTED)
+    set_target_properties(
+      grpc::gpr PROPERTIES
+      INTERFACE_INCLUDE_DIRECTORIES ${GRPC_INCLUDE_DIR}
+      IMPORTED_LOCATION ${GPR_LIBRARY}
+    )
+  endif()
+
+  if (NOT TARGET grpc::grpc)
+    set(
+      GRPC_LINK_LIBRARIES
+      c-ares::ares
+      grpc::gpr
+      OpenSSL::SSL
+      OpenSSL::Crypto
+      ZLIB::ZLIB
+    )
+
+    add_library(grpc::grpc UNKNOWN IMPORTED)
+    set_target_properties(
+      grpc::grpc PROPERTIES
+      INTERFACE_INCLUDE_DIRECTORIES ${GRPC_INCLUDE_DIR}
+      INTERFACE_LINK_LIBRARIES "${GRPC_LINK_LIBRARIES}"
+      IMPORTED_LOCATION ${GRPC_LIBRARY}
+    )
+  endif()
+endif(GRPC_FOUND)
diff --git a/cmake/FindLevelDB.cmake b/cmake/FindLevelDB.cmake
index 386a298..b664fa8 100644
--- a/cmake/FindLevelDB.cmake
+++ b/cmake/FindLevelDB.cmake
@@ -12,7 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-set(binary_dir ${FIREBASE_INSTALL_DIR}/third_party/leveldb/src/leveldb)
+set(binary_dir ${FIREBASE_INSTALL_DIR}/external/leveldb/src/leveldb)
 
 find_path(
   LEVELDB_INCLUDE_DIR leveldb/db.h
diff --git a/cmake/external/firestore.cmake b/cmake/external/firestore.cmake
index 1abb629..2d0ef02 100644
--- a/cmake/external/firestore.cmake
+++ b/cmake/external/firestore.cmake
@@ -14,27 +14,27 @@
 
 include(ExternalProject)
 
-set(source_dir ${PROJECT_SOURCE_DIR}/Firestore)
-set(binary_dir ${PROJECT_BINARY_DIR}/Firestore)
-
 ExternalProject_Add(
   Firestore
-  DEPENDS FirebaseCore googletest leveldb
+  DEPENDS
+    FirebaseCore
+    googletest
+    leveldb
+    grpc
 
   # Lay the binary directory out as if this were a subproject. This makes it
   # possible to build and test in it directly.
-  PREFIX ${binary_dir}
-  SOURCE_DIR ${source_dir}
-  BINARY_DIR ${binary_dir}
+  PREFIX ${PROJECT_BINARY_DIR}/external/Firestore
+  SOURCE_DIR ${PROJECT_SOURCE_DIR}/Firestore
+  BINARY_DIR ${PROJECT_BINARY_DIR}/Firestore
+
+  CMAKE_ARGS
+    -DCMAKE_BUILD_TYPE:STRING=${CMAKE_BUILD_TYPE}
+    -DCMAKE_INSTALL_PREFIX:PATH=${FIREBASE_INSTALL_DIR}
+    ${GTEST_CMAKE_ARGS}
+
   BUILD_ALWAYS ON
 
-  # Even though this isn't installed, set up the INSTALL_DIR so that
-  # find_package can find dependencies built from source.
-  INSTALL_DIR ${FIREBASE_INSTALL_DIR}
   INSTALL_COMMAND ""
   TEST_BEFORE_INSTALL ON
-
-  CMAKE_ARGS
-      -DCMAKE_BUILD_TYPE:STRING=${CMAKE_BUILD_TYPE}
-      -DCMAKE_INSTALL_PREFIX:PATH=<INSTALL_DIR>
 )
diff --git a/cmake/external/googletest.cmake b/cmake/external/googletest.cmake
index 128f849..c467b70 100644
--- a/cmake/external/googletest.cmake
+++ b/cmake/external/googletest.cmake
@@ -13,21 +13,44 @@
 # limitations under the License.
 
 include(ExternalProject)
+include(ExternalProjectFlags)
+
+ExternalProject_GitSource(
+  GOOGLETEST_GIT
+  GIT_REPOSITORY "https://github.com/google/googletest.git"
+  GIT_TAG "release-1.8.0"
+)
 
 ExternalProject_Add(
   googletest
+  DEPENDS
+    FirebaseCore  # for sequencing
 
-  GIT_REPOSITORY "https://github.com/google/googletest.git"
-  GIT_TAG "release-1.8.0"
+  ${GOOGLETEST_GIT}
 
-  PREFIX ${PROJECT_BINARY_DIR}/third_party/googletest
+  PREFIX ${PROJECT_BINARY_DIR}/external/googletest
 
-  INSTALL_DIR ${FIREBASE_INSTALL_DIR}
+  CMAKE_ARGS
+    -DCMAKE_BUILD_TYPE:STRING=${CMAKE_BUILD_TYPE}
+    -DBUILD_SHARED_LIBS:BOOL=OFF
 
+  INSTALL_COMMAND ""
   TEST_COMMAND ""
+)
 
-  CMAKE_ARGS
-      -DCMAKE_BUILD_TYPE:STRING=${CMAKE_BUILD_TYPE}
-      -DCMAKE_INSTALL_PREFIX:PATH=<INSTALL_DIR>
-      -DBUILD_SHARED_LIBS:BOOL=OFF
+ExternalProject_Get_Property(
+  googletest
+  SOURCE_DIR BINARY_DIR
+)
+
+# Arguments to pass to another CMake invocation so that it can find googletest
+# without installing it using the standard FindGTest module.
+set(GTEST_INCLUDE_DIR ${SOURCE_DIR}/googletest/include)
+set(GTEST_LIBRARY ${BINARY_DIR}/googlemock/gtest/libgtest.a)
+set(GTEST_MAIN_LIBRARY ${BINARY_DIR}/googlemock/gtest/libgtest_main.a)
+set(
+  GTEST_CMAKE_ARGS
+  -DGTEST_INCLUDE_DIR=${GTEST_INCLUDE_DIR}
+  -DGTEST_LIBRARY=${GTEST_LIBRARY}
+  -DGTEST_MAIN_LIBRARY=${GTEST_MAIN_LIBRARY}
 )
diff --git a/cmake/external/grpc.cmake b/cmake/external/grpc.cmake
new file mode 100644
index 0000000..fb54960
--- /dev/null
+++ b/cmake/external/grpc.cmake
@@ -0,0 +1,83 @@
+# Copyright 2018 Google
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+include(ExternalProject)
+include(ExternalProjectFlags)
+include(FindZLIB)
+
+if(GRPC_ROOT)
+  # If the user has supplied a GRPC_ROOT then just use it. Add an empty custom
+  # target so that the superbuild dependencies still work.
+  add_custom_target(grpc)
+
+else()
+  set(
+    GIT_SUBMODULES
+    third_party/boringssl
+    third_party/cares/cares
+  )
+
+  set(
+    CMAKE_ARGS
+    -DCMAKE_BUILD_TYPE:STRING=${CMAKE_BUILD_TYPE}
+    -DgRPC_BUILD_TESTS:BOOL=OFF
+    -DBUILD_SHARED_LIBS:BOOL=OFF
+  )
+
+  # zlib can be built by grpc but we can avoid it on platforms that provide it
+  # by default.
+  find_package(ZLIB)
+  if(ZLIB_FOUND)
+    list(
+      APPEND CMAKE_ARGS
+      -DgRPC_ZLIB_PROVIDER:STRING=package
+      -DZLIB_INCLUDE_DIR=${ZLIB_INCLUDE_DIR}
+      -DZLIB_LIBRARY=${ZLIB_LIBRARY}
+    )
+
+  else()
+    list(
+      APPEND GIT_SUBMODULES
+      third_party/zlib
+    )
+
+  endif(ZLIB_FOUND)
+
+  ExternalProject_GitSource(
+    GRPC_GIT
+    GIT_REPOSITORY "https://github.com/grpc/grpc.git"
+    GIT_TAG "v1.8.3"
+    GIT_SUBMODULES ${GIT_SUBMODULES}
+  )
+
+  ExternalProject_Add(
+    grpc
+    DEPENDS
+      leveldb  # for sequencing
+
+    ${GRPC_GIT}
+
+    PREFIX ${PROJECT_BINARY_DIR}/external/grpc
+
+    CMAKE_ARGS ${CMAKE_ARGS}
+
+    BUILD_COMMAND
+      ${CMAKE_COMMAND} --build . --target grpc
+
+    TEST_COMMAND ""
+    INSTALL_COMMAND ""
+  )
+
+endif(GRPC_ROOT)
+
diff --git a/cmake/external/leveldb.cmake b/cmake/external/leveldb.cmake
index b3b3fe1..5b2068a 100644
--- a/cmake/external/leveldb.cmake
+++ b/cmake/external/leveldb.cmake
@@ -13,6 +13,7 @@
 # limitations under the License.
 
 include(ExternalProject)
+include(ExternalProjectFlags)
 
 if(WIN32 OR LEVELDB_ROOT)
   # If the user has supplied a LEVELDB_ROOT then just use it. Add an empty
@@ -41,23 +42,38 @@ else()
       $<$<CONFIG:Release>:${CMAKE_CXX_FLAGS_RELEASE}>"
   )
 
+  ExternalProject_GitSource(
+    LEVELDB_GIT
+    GIT_REPOSITORY "https://github.com/google/leveldb.git"
+    GIT_TAG "v1.20"
+  )
+
   ExternalProject_Add(
     leveldb
+    DEPENDS
+      googletest  # for sequencing
 
-    GIT_REPOSITORY "https://github.com/google/leveldb.git"
-    GIT_TAG "v1.20"
+    ${LEVELDB_GIT}
 
-    PREFIX ${PROJECT_BINARY_DIR}/third_party/leveldb
+    PREFIX ${PROJECT_BINARY_DIR}/external/leveldb
 
+    # LevelDB's configuration is done in the Makefile
     CONFIGURE_COMMAND ""
-    BUILD_ALWAYS ON
+
+    # The Makefile-based build of leveldb does not support building
+    # out-of-source.
     BUILD_IN_SOURCE ON
+
+    # Only build the leveldb library skipping the tools and in-memory
+    # implementation we don't use.
     BUILD_COMMAND
-      env CXXFLAGS=${LEVELDB_CXX_FLAGS} OPT=${LEVELDB_OPT} make -j all
+      env CXXFLAGS=${LEVELDB_CXX_FLAGS} OPT=${LEVELDB_OPT}
+        make -j out-static/libleveldb.a
 
     INSTALL_DIR ${FIREBASE_INSTALL_DIR}
 
     INSTALL_COMMAND ""
     TEST_COMMAND ""
   )
+
 endif(WIN32 OR LEVELDB_ROOT)
diff --git a/cmake/xcodebuild.cmake b/cmake/xcodebuild.cmake
index 8312f6d..01a2961 100644
--- a/cmake/xcodebuild.cmake
+++ b/cmake/xcodebuild.cmake
@@ -33,7 +33,7 @@ function(xcodebuild framework)
   set(options "")
   set(single_value SCHEME WORKSPACE)
   set(multi_value DEPENDS)
-  cmake_parse_arguments(xcb "${options}" "${single_value}" "${multi_value}")
+  cmake_parse_arguments(xcb "${options}" "${single_value}" "${multi_value}" ${ARGN})
 
   if(NOT xcb_WORKSPACE)
     set(xcb_WORKSPACE ${PROJECT_SOURCE_DIR}/Example/Firebase.xcworkspace)
@@ -46,8 +46,6 @@ function(xcodebuild framework)
   set(destination "platform=macOS,arch=x86_64")
   set(scheme "${framework}-${platform}")
 
-  set(binary_dir ${PROJECT_BINARY_DIR}/${scheme})
-
   # CMake has a variety of release types, but Xcode has just one by default.
   if(CMAKE_BUILD_TYPE STREQUAL Debug)
     set(configuration Debug)
@@ -65,11 +63,11 @@ function(xcodebuild framework)
     ${framework}
     DEPENDS ${xcb_DEPENDS}
 
-    PREFIX ${binary_dir}
+    PREFIX ${PROJECT_BINARY_DIR}/external/${framework}
 
     # The source directory doesn't actually matter
     SOURCE_DIR ${PROJECT_SOURCE_DIR}
-    BINARY_DIR ${binary_dir}
+    BINARY_DIR ${PROJECT_BINARY_DIR}/Frameworks
 
     CONFIGURE_COMMAND ""
 
@@ -79,7 +77,7 @@ function(xcodebuild framework)
         -scheme ${scheme}
         -configuration ${configuration}
         -destination ${destination}
-        CONFIGURATION_BUILD_DIR=${FIREBASE_INSTALL_DIR}/Frameworks
+        CONFIGURATION_BUILD_DIR=<BINARY_DIR>
         build
         ${pipe_xcpretty}
     BUILD_ALWAYS ${BUILD_PODS}
@@ -87,4 +85,5 @@ function(xcodebuild framework)
     INSTALL_COMMAND ""
     TEST_COMMAND ""
   )
+
 endfunction()