Add a CMake external build for c-ares (#1472)

* Add an external build for c-ares

* Use installed c-ares package configuration

* Adjust protobuf configuration to use the standard Protobuf_DIR variable.

* Have grpc depend on c-ares

* Drop UPDATE_COMMAND where it doesn't matter

9 files changed, 59 insertions, 25 deletions

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 84722d8..a935c4d 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -56,5 +56,6 @@ include(external/zlib)
 include(external/leveldb)
 include(external/protobuf)
 include(external/nanopb)
+include(external/c-ares)
 include(external/grpc)
 include(external/firestore)
diff --git a/cmake/FindGRPC.cmake b/cmake/FindGRPC.cmake
index 22c9655..ba8f857 100644
--- a/cmake/FindGRPC.cmake
+++ b/cmake/FindGRPC.cmake
@@ -56,20 +56,10 @@ 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()
+if(NOT c-ares_DIR)
+  set(c-ares_DIR ${FIREBASE_INSTALL_DIR}/lib/cmake/c-ares)
 endif()
+find_package(c-ares CONFIG REQUIRED)
 
 
 ## GRPC
@@ -124,7 +114,7 @@ if(GRPC_FOUND)
   if (NOT TARGET grpc::grpc)
     set(
       GRPC_LINK_LIBRARIES
-      c-ares::ares
+      c-ares::cares
       grpc::gpr
       OpenSSL::SSL
       OpenSSL::Crypto
diff --git a/cmake/external/c-ares.cmake b/cmake/external/c-ares.cmake
new file mode 100644
index 0000000..4c866c1
--- /dev/null
+++ b/cmake/external/c-ares.cmake
@@ -0,0 +1,34 @@
+# 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)
+
+ExternalProject_Add(
+  c-ares
+
+  DOWNLOAD_DIR ${FIREBASE_DOWNLOAD_DIR}
+  URL https://github.com/c-ares/c-ares/archive/cares-1_14_0.tar.gz
+  URL_HASH SHA256=62dd12f0557918f89ad6f5b759f0bf4727174ae9979499f5452c02be38d9d3e8
+
+  PREFIX ${PROJECT_BINARY_DIR}/external/cares
+
+  CMAKE_ARGS
+    -DCMAKE_BUILD_TYPE:STRING=${CMAKE_BUILD_TYPE}
+    -DCMAKE_INSTALL_PREFIX:STRING=${FIREBASE_INSTALL_DIR}
+    -DCARES_STATIC:BOOL=ON
+    -DCARES_SHARED:BOOL=OFF
+    -DCARES_STATIC_PIC:BOOL=ON
+
+  TEST_COMMAND ""
+)
diff --git a/cmake/external/googletest.cmake b/cmake/external/googletest.cmake
index 3af136e..b80c098 100644
--- a/cmake/external/googletest.cmake
+++ b/cmake/external/googletest.cmake
@@ -27,6 +27,5 @@ ExternalProject_Add(
   CMAKE_CACHE_ARGS
     -DCMAKE_INSTALL_PREFIX:STRING=${FIREBASE_INSTALL_DIR}
 
-  UPDATE_COMMAND ""
   TEST_COMMAND ""
 )
diff --git a/cmake/external/grpc.cmake b/cmake/external/grpc.cmake
index 1e8388c..a789838 100644
--- a/cmake/external/grpc.cmake
+++ b/cmake/external/grpc.cmake
@@ -24,7 +24,6 @@ else()
   set(
     GIT_SUBMODULES
     third_party/boringssl
-    third_party/cares/cares
   )
 
   set(
@@ -46,23 +45,37 @@ else()
   )
 
 
+  ## c-ares
+  if(NOT c-ares_DIR)
+    set(c-ares_DIR ${FIREBASE_INSTALL_DIR}/lib/cmake/c-ares)
+  endif()
+
+  list(
+    APPEND CMAKE_ARGS
+    -DgRPC_CARES_PROVIDER:STRING=package
+    -Dc-ares_DIR:PATH=${c-ares_DIR}
+  )
+
+
   ## protobuf
 
   # Unlike other dependencies of gRPC, we control the protobuf version because we
   # have checked-in protoc outputs that must match the runtime.
 
   # The location where protobuf-config.cmake will be installed varies by platform
-  if (WIN32)
-    set(PROTOBUF_CMAKE_DIR "${FIREBASE_INSTALL_DIR}/cmake")
-  else()
-    set(PROTOBUF_CMAKE_DIR "${FIREBASE_INSTALL_DIR}/lib/cmake/protobuf")
+  if(NOT Protobuf_DIR)
+    if(WIN32)
+      set(Protobuf_DIR "${FIREBASE_INSTALL_DIR}/cmake")
+    else()
+      set(Protobuf_DIR "${FIREBASE_INSTALL_DIR}/lib/cmake/protobuf")
+    endif()
   endif()
 
   list(
     APPEND CMAKE_ARGS
     -DgRPC_PROTOBUF_PROVIDER:STRING=package
     -DgRPC_PROTOBUF_PACKAGE_TYPE:STRING=CONFIG
-    -DProtobuf_DIR:PATH=${PROTOBUF_CMAKE_DIR}
+    -DProtobuf_DIR:PATH=${Protobuf_DIR}
   )
 
 
@@ -94,6 +107,7 @@ else()
   ExternalProject_Add(
     grpc
     DEPENDS
+      c-ares
       protobuf
       zlib
 
diff --git a/cmake/external/leveldb.cmake b/cmake/external/leveldb.cmake
index db8aa4c..9daab02 100644
--- a/cmake/external/leveldb.cmake
+++ b/cmake/external/leveldb.cmake
@@ -66,7 +66,6 @@ else()
 
     INSTALL_DIR ${FIREBASE_INSTALL_DIR}
 
-    UPDATE_COMMAND ""
     INSTALL_COMMAND ""
     TEST_COMMAND ""
   )
diff --git a/cmake/external/nanopb.cmake b/cmake/external/nanopb.cmake
index 39eb833..b5c74ce 100644
--- a/cmake/external/nanopb.cmake
+++ b/cmake/external/nanopb.cmake
@@ -34,6 +34,5 @@ ExternalProject_Add(
     -Dnanopb_BUILD_GENERATOR:BOOL=ON
     -Dnanopb_PROTOC_PATH:STRING=${NANOPB_PROTOC_BIN}
 
-  UPDATE_COMMAND ""
   TEST_COMMAND ""
 )
diff --git a/cmake/external/protobuf.cmake b/cmake/external/protobuf.cmake
index 66d1426..e8060b2 100644
--- a/cmake/external/protobuf.cmake
+++ b/cmake/external/protobuf.cmake
@@ -105,6 +105,5 @@ ExternalProject_Add(
 
   ${commands}
 
-  UPDATE_COMMAND ""
   TEST_COMMAND ""
 )
diff --git a/cmake/external/zlib.cmake b/cmake/external/zlib.cmake
index 4744fe9..a90a511 100644
--- a/cmake/external/zlib.cmake
+++ b/cmake/external/zlib.cmake
@@ -35,7 +35,6 @@ else()
       -DCMAKE_INSTALL_PREFIX:STRING=${FIREBASE_INSTALL_DIR}
       -DBUILD_SHARED_LIBS:BOOL=OFF
 
-    UPDATE_COMMAND ""
     TEST_COMMAND ""
   )
 endif()