1 files changed, 78 insertions, 0 deletions
diff --git a/cmake/libgav1_variables.cmake b/cmake/libgav1_variables.cmake
new file mode 100644
index 0000000..0dd0f37
--- /dev/null
+++ b/cmake/libgav1_variables.cmake
@@ -0,0 +1,78 @@
+# Copyright 2019 The libgav1 Authors
+#
+# 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.
+
+if(LIBGAV1_CMAKE_LIBGAV1_VARIABLES_CMAKE_)
+  return()
+endif() # LIBGAV1_CMAKE_LIBGAV1_VARIABLES_CMAKE_
+set(LIBGAV1_CMAKE_LIBGAV1_VARIABLES_CMAKE_ 1)
+
+# Halts generation when $variable_name does not refer to a directory that
+# exists.
+macro(libgav1_variable_must_be_directory variable_name)
+  if("${variable_name}" STREQUAL "")
+    message(
+      FATAL_ERROR
+        "Empty variable_name passed to libgav1_variable_must_be_directory.")
+  endif()
+
+  if("${${variable_name}}" STREQUAL "")
+    message(
+      FATAL_ERROR
+        "Empty variable ${variable_name} is required to build libgav1.")
+  endif()
+
+  if(NOT IS_DIRECTORY "${${variable_name}}")
+    message(
+      FATAL_ERROR
+        "${variable_name}, which is ${${variable_name}}, does not refer to a\n"
+        "directory.")
+  endif()
+endmacro()
+
+# Adds $var_name to the tracked variables list.
+macro(libgav1_track_configuration_variable var_name)
+  if(LIBGAV1_VERBOSE GREATER 2)
+    message("---- libgav1_track_configuration_variable ----\n"
+            "var_name=${var_name}\n"
+            "----------------------------------------------\n")
+  endif()
+
+  list(APPEND libgav1_configuration_variables ${var_name})
+  list(REMOVE_DUPLICATES libgav1_configuration_variables)
+endmacro()
+
+# Logs current C++ and executable linker flags via CMake's message command.
+macro(libgav1_dump_cmake_flag_variables)
+  unset(flag_variables)
+  list(APPEND flag_variables "CMAKE_CXX_FLAGS_INIT" "CMAKE_CXX_FLAGS"
+              "CMAKE_EXE_LINKER_FLAGS_INIT" "CMAKE_EXE_LINKER_FLAGS")
+  if(CMAKE_BUILD_TYPE)
+    list(APPEND flag_variables "CMAKE_BUILD_TYPE"
+                "CMAKE_CXX_FLAGS_${CMAKE_BUILD_TYPE}_INIT"
+                "CMAKE_CXX_FLAGS_${CMAKE_BUILD_TYPE}"
+                "CMAKE_EXE_LINKER_FLAGS_${CMAKE_BUILD_TYPE}_INIT"
+                "CMAKE_EXE_LINKER_FLAGS_${CMAKE_BUILD_TYPE}")
+  endif()
+  foreach(flag_variable ${flag_variables})
+    message("${flag_variable}:${${flag_variable}}")
+  endforeach()
+endmacro()
+
+# Dumps the variables tracked in $libgav1_configuration_variables via CMake's
+# message command.
+macro(libgav1_dump_tracked_configuration_variables)
+  foreach(config_variable ${libgav1_configuration_variables})
+    message("${config_variable}:${${config_variable}}")
+  endforeach()
+endmacro()