Add more CMake helper scripts plus more CMake updates.

- Disallow in-tree CMake runs.
- Adds back CONTRIBUTING.md.

This fixes #130 and hopefully addresses #163.

CMakeLists.txt

@@ -5,6 +5,14 @@ set(draco_root "${CMAKE_CURRENT_SOURCE_DIR}")
 set(draco_src_root "${draco_root}/src/draco")
 set(draco_build_dir "${CMAKE_BINARY_DIR}")
 
+if ("${draco_root}" STREQUAL "${draco_build_dir}")
+  message(FATAL_ERROR
+          "Building from within the Draco source tree is not supported.\n"
+          "Hint: mkdir -p ../draco_build && cd ../draco_build\n"
+          "Run cmake from there.")
+endif ()
+
+include(CMakePackageConfigHelpers)
 include("${draco_root}/cmake/compiler_flags.cmake")
 include("${draco_root}/cmake/util.cmake")
 
@@ -772,22 +780,12 @@ else ()
     set_target_properties(draco PROPERTIES SOVERSION 1)
   endif ()
 
+  extract_version_string("${draco_src_root}/core/draco_version.h" draco_version)
+
   if (NOT MSVC)
     # Generate draco.pc.
-
-    # Extract the version string.
-    file(STRINGS "${draco_src_root}/core/draco_version.h" draco_version
-         REGEX "kDracoVersion\\[\\]")
-    list(GET draco_version 0 draco_version)
-    string(REPLACE "static const char kDracoVersion[] = " "" draco_version
-           "${draco_version}")
-    string(REPLACE ";" "" draco_version "${draco_version}")
-    string(REPLACE "\"" "" draco_version "${draco_version}")
-
     set(prefix "${CMAKE_INSTALL_PREFIX}")
     set(pkgconfig_file "${draco_build_dir}/draco.pc")
-
-    # Write aom.pc.
     file(WRITE "${pkgconfig_file}" "# draco pkg-config.\n")
     file(APPEND "${pkgconfig_file}" "prefix=${prefix}\n")
     file(APPEND "${pkgconfig_file}" "exec_prefix=${prefix}/bin\n")
@@ -836,8 +834,41 @@ else ()
           DESTINATION "${CMAKE_INSTALL_PREFIX}/lib")
   install(TARGETS draco_decoder draco_encoder DESTINATION
           "${CMAKE_INSTALL_PREFIX}/bin")
-  install(FILES "${draco_root}/cmake/FindDraco.cmake"
-          DESTINATION "${CMAKE_INSTALL_PREFIX}/include/draco/cmake")
+
+  # Generate a CMake config file.
+  set(draco_include_install_dir "include/draco")
+  set(draco_lib_install_dir "lib")
+  set(draco_script_install_dir
+      "${CMAKE_INSTALL_PREFIX}/${draco_lib_install_dir}/draco/cmake")
+  set(draco_config_in_file "${draco_root}/cmake/DracoConfig.cmake")
+  set(draco_config_out_file "${draco_build_dir}/DracoConfig.cmake")
+
+  configure_package_config_file(
+      "${draco_config_in_file}"
+      "${draco_config_out_file}"
+      NO_CHECK_REQUIRED_COMPONENTS_MACRO
+      INSTALL_DESTINATION "${draco_lib_install_dir}/draco/cmake"
+      PATH_VARS draco_include_install_dir draco_lib_install_dir)
+  write_basic_package_version_file(
+      "${draco_build_dir}/DracoConfigVersion.cmake"
+      VERSION ${draco_version}
+      COMPATIBILITY SameMajorVersion)
+
+  # Read in the config file and rewrite it with a version string included.
+  file(STRINGS "${draco_config_out_file}" draco_config_strings)
+  file(WRITE "${draco_config_out_file}"
+       "set(draco_VERSION \"${draco_version}\")\n")
+  foreach (config_string ${draco_config_strings})
+    file(APPEND "${draco_config_out_file}" "${config_string}\n")
+  endforeach ()
+
+  # Add install rules for CMake helper scripts.
+  set(draco_cmake_helper_scripts
+      "${draco_root}/cmake/FindDraco.cmake"
+      "${draco_build_dir}/DracoConfig.cmake"
+      "${draco_build_dir}/DracoConfigVersion.cmake")
+  install(FILES ${draco_cmake_helper_scripts}
+          DESTINATION "${draco_script_install_dir}")
 
   # Some generators complain about unknown link language for header only
   # targets. Silence the harmless warnings/errors with some dummy source files.

CONTRIBUTING.md

@@ -0,0 +1,27 @@
+Want to contribute? Great! First, read this page (including the small print at the end).
+
+### Before you contribute
+Before we can use your code, you must sign the
+[Google Individual Contributor License Agreement]
+(https://cla.developers.google.com/about/google-individual)
+(CLA), which you can do online. The CLA is necessary mainly because you own the
+copyright to your changes, even after your contribution becomes part of our
+codebase, so we need your permission to use and distribute your code. We also
+need to be sure of various other things—for instance that you'll tell us if you
+know that your code infringes on other people's patents. You don't have to sign
+the CLA until after you've submitted your code for review and a member has
+approved it, but you must do it before we can put your code into our codebase.
+Before you start working on a larger contribution, you should get in touch with
+us first through the issue tracker with your idea so that we can help out and
+possibly guide you. Coordinating up front makes it much easier to avoid
+frustration later on.
+
+### Code reviews
+All submissions, including submissions by project members, require review. We
+use GitHub pull requests for this purpose.
+
+### The small print
+Contributions made by corporations are covered by a different agreement than
+the one above, the
+[Software Grant and Corporate Contributor License Agreement]
+(https://cla.developers.google.com/about/google-corporate).

cmake/DracoConfig.cmake

@@ -0,0 +1,3 @@
+@PACKAGE_INIT@
+set_and_check(draco_INCLUDE_DIR "@PACKAGE_draco_include_install_dir@")
+set_and_check(draco_LIBRARY_DIR "@PACKAGE_draco_lib_install_dir@")

cmake/FindDraco.cmake

@@ -1,58 +1,58 @@
-# FindDraco
+# Finddraco
 #
-# Locates Draco and sets the following variables:
+# Locates draco and sets the following variables:
 #
-# Drace_FOUND
-# Draco_INCLUDE_DIRS
-# Draco_LIBARY_DIRS
-# Draco_LIBRARIES
-# Draco_VERSION_STRING
+# draco_FOUND
+# draco_INCLUDE_DIRS
+# draco_LIBARY_DIRS
+# draco_LIBRARIES
+# draco_VERSION_STRING
 #
-# Draco_FOUND is set to YES only when all other variables are successfully
+# draco_FOUND is set to YES only when all other variables are successfully
 # configured.
 
-unset(Draco_FOUND)
-unset(Draco_INCLUDE_DIRS)
-unset(Draco_LIBRARY_DIRS)
-unset(Draco_LIBRARIES)
-unset(Draco_VERSION_STRING)
+unset(draco_FOUND)
+unset(draco_INCLUDE_DIRS)
+unset(draco_LIBRARY_DIRS)
+unset(draco_LIBRARIES)
+unset(draco_VERSION_STRING)
 
-mark_as_advanced(Draco_FOUND)
-mark_as_advanced(Draco_INCLUDE_DIRS)
-mark_as_advanced(Draco_LIBRARY_DIRS)
-mark_as_advanced(Draco_LIBRARIES)
-mark_as_advanced(Draco_VERSION_STRING)
+mark_as_advanced(draco_FOUND)
+mark_as_advanced(draco_INCLUDE_DIRS)
+mark_as_advanced(draco_LIBRARY_DIRS)
+mark_as_advanced(draco_LIBRARIES)
+mark_as_advanced(draco_VERSION_STRING)
 
-set(Draco_version_file_no_prefix "draco/src/draco/core/draco_version.h")
+set(draco_version_file_no_prefix "draco/src/draco/core/draco_version.h")
 
-# Set Draco_INCLUDE_DIRS
-find_path(Draco_INCLUDE_DIRS NAMES "${Draco_version_file_no_prefix}")
+# Set draco_INCLUDE_DIRS
+find_path(draco_INCLUDE_DIRS NAMES "${draco_version_file_no_prefix}")
 
 #  Extract the version string from draco_version.h.
-if (Draco_INCLUDE_DIRS)
-  set(Draco_version_file
-      "${Draco_INCLUDE_DIRS}/draco/src/draco/core/draco_version.h")
-  file(STRINGS "${Draco_version_file}" draco_version
-       REGEX "kDracoVersion")
+if (draco_INCLUDE_DIRS)
+  set(draco_version_file
+      "${draco_INCLUDE_DIRS}/draco/src/draco/core/draco_version.h")
+  file(STRINGS "${draco_version_file}" draco_version
+       REGEX "kdracoVersion")
   list(GET draco_version 0 draco_version)
-  string(REPLACE "static const char kDracoVersion[] = " "" draco_version
+  string(REPLACE "static const char kdracoVersion[] = " "" draco_version
          "${draco_version}")
   string(REPLACE ";" "" draco_version "${draco_version}")
   string(REPLACE "\"" "" draco_version "${draco_version}")
-  set(Draco_VERSION_STRING ${draco_version})
+  set(draco_VERSION_STRING ${draco_version})
 endif ()
 
 # Find the library.
 if (BUILD_SHARED_LIBS)
-  find_library(Draco_LIBRARIES NAMES draco.dll libdraco.dylib libdraco.so)
+  find_library(draco_LIBRARIES NAMES draco.dll libdraco.dylib libdraco.so)
 else ()
-  find_library(Draco_LIBRARIES NAMES draco.lib libdraco.a)
+  find_library(draco_LIBRARIES NAMES draco.lib libdraco.a)
 endif ()
 
 # Store path to library.
-get_filename_component(Draco_LIBRARY_DIRS ${Draco_LIBRARIES} DIRECTORY)
+get_filename_component(draco_LIBRARY_DIRS ${draco_LIBRARIES} DIRECTORY)
 
-if (Draco_INCLUDE_DIRS AND Draco_LIBRARY_DIRS AND Draco_LIBRARIES AND
-    Draco_VERSION_STRING)
-  set(Draco_FOUND YES)
+if (draco_INCLUDE_DIRS AND draco_LIBRARY_DIRS AND draco_LIBRARIES AND
+    draco_VERSION_STRING)
+  set(draco_FOUND YES)
 endif ()

cmake/util.cmake

@@ -16,5 +16,15 @@ function (add_dummy_source_file_to_target target_name extension)
   target_sources(${target_name} PRIVATE ${dummy_source_file})
 endfunction ()
 
+function (extract_version_string version_file version_string_out_var)
+  file(STRINGS "${version_file}" draco_version REGEX "kDracoVersion")
+  list(GET draco_version 0 draco_version)
+  string(REPLACE "static const char kDracoVersion[] = " "" draco_version
+         "${draco_version}")
+  string(REPLACE ";" "" draco_version "${draco_version}")
+  string(REPLACE "\"" "" draco_version "${draco_version}")
+  set("${version_string_out_var}" "${draco_version}" PARENT_SCOPE)
+endfunction ()
+
 endif()  # DRACO_CMAKE_UTIL_CMAKE_