Build gRPC for Firestore C++ (#652)

* Clean up quoting and other minor issues

* Reorganize CMake build output

Make it clearer which parts of the output pertain to external projects.

* Use a consistent ordering of ExternalProject arguments

* Prevent the top-level build from running in parallel

This prevents spurious failures when running make -j.

* Actually parse arguments in the xcodebuild function

* Use ExternalProject features when available

  * submodule limits from CMake 3.0
  * shallow clones from CMake 3.6
  * git progress output from CMake 3.8

* Only build the parts of leveldb we need

Skip building the tools and other libraries

* Avoid installing ExternalProjects

Consume build output directly so that we can build just the targets we
need. Installing causes all targets to be built.

This doesn't matter as much for these targets but the gRPC build
includes a ton of stuff we don't need so it's worth adopting this as a
general strategy.

* Define an external build for grpc

* Test that grpc can link successfully.

* Add a FindGRPC CMake module

* Actually comment ExternalProjext_GitSource

Author: wilhuff

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)

Firestore/CMakeLists.txt

@@ -13,23 +13,24 @@
 # 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
 # superbuild (i.e. by invoking cmake on the directory above this).
 #
 # 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)

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)

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
+)

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

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_

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
+)

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();
+}

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()