Ninja: Add the Ninja generator

1 files changed, 17 insertions, 2 deletions

diff --git a/Modules/ExternalProject.cmake b/Modules/ExternalProject.cmake
index fb55d3b..b6fe190 100644
--- a/Modules/ExternalProject.cmake
+++ b/Modules/ExternalProject.cmake
@@ -833,6 +833,12 @@ function(ExternalProject_Add_StepTargets name)
   foreach(step ${steps})
     add_custom_target(${name}-${step}
       DEPENDS ${stamp_dir}${cfgdir}/${name}-${step})
+
+    # Depend on other external projects (target-level).
+    get_property(deps TARGET ${name} PROPERTY _EP_DEPENDS)
+    foreach(arg IN LISTS deps)
+      add_dependencies(${name}-${step} ${arg})
+    endforeach()
   endforeach()
 endfunction(ExternalProject_Add_StepTargets)
 
@@ -1451,9 +1457,18 @@ function(ExternalProject_Add name)
   # depends on the 'done' mark so that it rebuilds when this project
   # rebuilds.  It is important that 'done' is not the output of any
   # custom command so that CMake does not propagate build rules to
-  # other external project targets.
+  # other external project targets, which may cause problems during
+  # parallel builds.  However, the Ninja generator needs to see the entire
+  # dependency graph, and can cope with custom commands belonging to
+  # multiple targets, so we add the 'done' mark as an output for Ninja only.
+  set(complete_outputs ${cmf_dir}${cfgdir}/${name}-complete)
+  if(${CMAKE_GENERATOR} MATCHES "Ninja")
+    set(complete_outputs
+        ${complete_outputs} ${stamp_dir}${cfgdir}/${name}-done)
+  endif()
+
   add_custom_command(
-    OUTPUT ${cmf_dir}${cfgdir}/${name}-complete
+    OUTPUT ${complete_outputs}
     COMMENT "Completed '${name}'"
     COMMAND ${CMAKE_COMMAND} -E make_directory ${cmf_dir}${cfgdir}
     COMMAND ${CMAKE_COMMAND} -E touch ${cmf_dir}${cfgdir}/${name}-complete