ARROW-29: [C++] FindRe2 cmake module

cpp/cmake_modules/FindRe2.cmake

@@ -0,0 +1,69 @@
+##############################################################################
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you 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.
+##############################################################################
+
+# - Find re2 headers and lib.
+# RE2_HOME hints the location
+# This module defines
+#  RE2_INCLUDE_DIR, directory containing headers
+#  RE2_STATIC_LIB, path to libre2.a
+#  re2 imported static library
+#  RE2_FOUND, whether re2 has been found
+
+set(RE2_SEARCH_HEADER_PATHS ${RE2_HOME}/include)
+
+set(RE2_SEARCH_LIB_PATHS ${RE2_HOME}/lib)
+
+find_path(RE2_INCLUDE_DIR re2/re2.h
+  PATHS ${RE2_SEARCH_HEADER_PATHS}
+        NO_DEFAULT_PATH
+  DOC  "Google's re2 regex header path"
+)
+
+find_library(RE2_LIBS NAMES re2
+  PATHS ${RE2_SEARCH_LIB_PATHS}
+        NO_DEFAULT_PATH
+  DOC   "Google's re2 regex library"
+)
+
+find_library(RE2_STATIC_LIB NAMES libre2${CMAKE_STATIC_LIBRARY_SUFFIX}
+  PATHS ${RE2_SEARCH_LIB_PATHS}
+        NO_DEFAULT_PATH
+  DOC   "Google's re2 regex static library"
+)
+
+message(STATUS ${RE2_INCLUDE_DIR})
+
+if (NOT RE2_INCLUDE_DIR OR NOT RE2_LIBS OR
+    NOT RE2_STATIC_LIB)
+  set(RE2_FOUND FALSE)
+  message(FATAL_ERROR "Re2 includes and libraries NOT found. "
+    "Looked for headers in ${RE2_SEARCH_HEADER_PATHS}, "
+    "and for libs in ${RE2_SEARCH_LIB_PATHS}")
+else()
+    set(RE2_FOUND TRUE)
+    add_library(re2 STATIC IMPORTED)
+    set_target_properties(re2 PROPERTIES IMPORTED_LOCATION "${RE2_STATIC_LIB}")
+endif()
+
+mark_as_advanced(
+  RE2_INCLUDE_DIR
+  RE2_LIBS
+  RE2_STATIC_LIB
+  re2
+)