Initial open sourcing of MuJoCo.

PiperOrigin-RevId: 450374687
Change-Id: Ie3225a46ce095fc28ae8e63c326a640261f562bb

cmake/FindOrFetch.cmake

@@ -31,8 +31,9 @@
 #
 # Arguments:
 #  - ``USE_SYSTEM_PACKAGE`` one-value argument on whether to search for the
-#    package in the system (ON) or whether to fetch the library from a git
-#    repository (OFF).
+#    package in the system (ON) or whether to fetch the library using
+#    FetchContent from the specified Git repository (OFF). Note that
+#    FetchContent variables will override this behaviour.
 #  - ``PACKAGE_NAME`` name of the system-package. Ignored if
 #    ``USE_SYSTEM_PACKAGE`` is ``OFF``.
 #  - ``LIBRARY_NAME`` name of the library. Ignored if
@@ -41,9 +42,19 @@
 #    ``USE_SYSTEM_PACKAGE`` is ``ON``.
 #  - ``GIT_TAG`` tag reference when fetching the library from the git
 #    repository. Ignored if ``USE_SYSTEM_PACKAGE`` is ``ON``.
+#  - ``PATCH_COMMAND`` Specifies a custom command to patch the sources after an
+#    update. See https://cmake.org/cmake/help/latest/module/ExternalProject.html#command:externalproject_add
+#    for details on the parameter.
 #  - ``TARGETS`` list of targets to be satisfied. If any of these targets are
 #    not currently defined, this macro will attempt to either find or fetch the
 #    package.
+#  - ``EXCLUDE_FROM_ALL`` if specified, the targets are not added to the ``all``
+#    metatarget.
+#
+# Note: if ``USE_SYSTEM_PACKAGE`` is ``OFF``, FetchContent will be used to
+# retrieve the specified targets. It is possible to specify any variable in
+# https://cmake.org/cmake/help/latest/module/FetchContent.html#variables to
+# override this macro behaviour.
 
 if(COMMAND FindOrFetch)
   return()
@@ -76,10 +87,14 @@ macro(FindOrFetch)
   if(NOT _ARGS_TARGETS)
     message(FATAL_ERROR "mujoco::FindOrFetch: TARGETS must be specified.")
   endif()
+
   set(targets_found TRUE)
+  message(CHECK_START
+          "mujoco::FindOrFetch: checking for targets in package `${_ARGS_PACKAGE_NAME}`"
+  )
   foreach(target ${_ARGS_TARGETS})
     if(NOT TARGET ${target})
-      message(STATUS "mujoco::FindOrFetch: target `${target}` not defined.")
+      message(CHECK_FAIL "target `${target}` not defined.")
       set(targets_found FALSE)
       break()
     endif()
@@ -88,16 +103,14 @@ macro(FindOrFetch)
   # If targets are not found, use `find_package` or `FetchContent...` to get it.
   if(NOT targets_found)
     if(${_ARGS_USE_SYSTEM_PACKAGE})
-      message(
-        STATUS
-          "mujoco::FindOrFetch: Attempting to find `${_ARGS_PACKAGE_NAME}` in system packages..."
+      message(CHECK_START
+              "mujoco::FindOrFetch: finding `${_ARGS_PACKAGE_NAME}` in system packages..."
       )
       find_package(${_ARGS_PACKAGE_NAME} REQUIRED)
-      message(STATUS "mujoco::FindOrFetch: Found `${_ARGS_PACKAGE_NAME}` in system packages.")
+      message(CHECK_PASS "found")
     else()
-      message(
-        STATUS
-          "mujoco::FindOrFetch: Attempting to fetch `${_ARGS_LIBRARY_NAME}` from `${_ARGS_GIT_REPO}`..."
+      message(CHECK_START
+              "mujoco::FindOrFetch: Using FetchContent to retrieve `${_ARGS_LIBRARY_NAME}`"
       )
       FetchContent_Declare(
         ${_ARGS_LIBRARY_NAME}
@@ -118,11 +131,9 @@ macro(FindOrFetch)
       else()
         FetchContent_MakeAvailable(${_ARGS_LIBRARY_NAME})
       endif()
-      message(
-        STATUS "mujoco::FindOrFetch: Fetched `${_ARGS_LIBRARY_NAME}` from `${_ARGS_GIT_REPO}`."
-      )
+      message(CHECK_PASS "Done")
     endif()
   else()
-    message(STATUS "mujoco::FindOrFetch: `${_ARGS_PACKAGE_NAME}` targets found.")
+    message(CHECK_PASS "found")
   endif()
 endmacro()