From 3f606fa7d06a209cc2cd3a97afb84951d1c4c033 Mon Sep 17 00:00:00 2001
From: "Daniele E. Domenichelli" <daniele.domenichelli@iit.it>
Date: Wed, 5 Nov 2014 00:31:40 +0100
Subject: [PATCH] ExternalProject: Add UPDATE_DISCONNECTED option

If UPDATE_DISCONNECTED is set, the update step is not executed
automatically when building the main target. The update step can still
be added as a step target and called manually. This is useful if you
want to allow to build the project when you are disconnected from the
network (you might still need the network for the download step).
This is disabled by default.

The directory property EP_UPDATE_DISCONNECTED can be used to change
the default value for all the external projects in the current
directory and its subdirectories.
---
 Modules/ExternalProject.cmake | 55 ++++++++++++++++++++++++++++++++++-
 1 file changed, 54 insertions(+), 1 deletion(-)

diff --git a/Modules/ExternalProject.cmake b/Modules/ExternalProject.cmake
index bf6cd21e8..a9c7519eb 100644
--- a/Modules/ExternalProject.cmake
+++ b/Modules/ExternalProject.cmake
@@ -80,6 +80,8 @@ Create custom targets to build projects in external trees
 
   ``UPDATE_COMMAND <cmd>...``
     Source work-tree update command
+  ``UPDATE_DISCONNECTED 1``
+    Never update automatically from the remote repository
   ``PATCH_COMMAND <cmd>...``
     Command to patch downloaded source
 
@@ -203,6 +205,16 @@ Create custom targets to build projects in external trees
   options.  The ``URL`` option may refer locally to a directory or source
   tarball, or refer to a remote tarball (e.g. ``http://.../src.tgz``).
 
+  If ``UPDATE_DISCONNECTED`` is set, the update step is not executed
+  automatically when building the main target. The update step can still
+  be added as a step target and called manually. This is useful if you
+  want to allow to build the project when you are disconnected from the
+  network (you might still need the network for the download step).
+  This is disabled by default.
+  The directory property ``EP_UPDATE_DISCONNECTED`` can be used to change
+  the default value for all the external projects in the current
+  directory and its subdirectories.
+
 .. command:: ExternalProject_Add_Step
 
   The ``ExternalProject_Add_Step`` function adds a custom step to an
@@ -439,6 +451,13 @@ define_property(DIRECTORY PROPERTY "EP_INDEPENDENT_STEP_TARGETS" INHERITED
   "ExternalProject module."
   )
 
+define_property(DIRECTORY PROPERTY "EP_UPDATE_DISCONNECTED" INHERITED
+  BRIEF_DOCS "Never update automatically from the remote repo."
+  FULL_DOCS
+  "See documentation of the ExternalProject_Add() function in the "
+  "ExternalProject module."
+  )
+
 function(_ep_write_gitclone_script script_filename source_dir git_EXECUTABLE git_repository git_tag git_submodules src_name work_dir gitclone_infofile gitclone_stampfile)
   file(WRITE ${script_filename}
 "if(\"${git_tag}\" STREQUAL \"\")
@@ -1825,6 +1844,12 @@ function(_ep_add_update_command name)
   get_property(svn_repository TARGET ${name} PROPERTY _EP_SVN_REPOSITORY)
   get_property(git_repository TARGET ${name} PROPERTY _EP_GIT_REPOSITORY)
   get_property(hg_repository  TARGET ${name} PROPERTY _EP_HG_REPOSITORY )
+  get_property(update_disconnected_set TARGET ${name} PROPERTY _EP_UPDATE_DISCONNECTED SET)
+  if(update_disconnected_set)
+    get_property(update_disconnected TARGET ${name} PROPERTY _EP_UPDATE_DISCONNECTED)
+  else()
+    get_property(update_disconnected DIRECTORY PROPERTY EP_UPDATE_DISCONNECTED)
+  endif()
 
   set(work_dir)
   set(comment)
@@ -1914,10 +1939,26 @@ Update to Mercurial >= 2.1.1.
     COMMENT ${comment}
     COMMAND ${cmd}
     ALWAYS ${always}
+    EXCLUDE_FROM_MAIN ${update_disconnected}
     WORKING_DIRECTORY ${work_dir}
     DEPENDEES download
     ${log}
     )
+
+  if(always AND update_disconnected)
+    _ep_get_step_stampfile(${name} skip-update skip-update_stamp_file)
+    string(REPLACE "Performing" "Skipping" comment "${comment}")
+    ExternalProject_Add_Step(${name} skip-update
+      COMMENT ${comment}
+      ALWAYS 1
+      EXCLUDE_FROM_MAIN 1
+      WORKING_DIRECTORY ${work_dir}
+      DEPENDEES download
+      ${log}
+    )
+    set_property(SOURCE ${skip-update_stamp_file} PROPERTY SYMBOLIC 1)
+  endif()
+
 endfunction()
 
 
@@ -2039,10 +2080,22 @@ function(_ep_add_configure_command name)
     set(log "")
   endif()
 
+  get_property(update_disconnected_set TARGET ${name} PROPERTY _EP_UPDATE_DISCONNECTED SET)
+  if(update_disconnected_set)
+    get_property(update_disconnected TARGET ${name} PROPERTY _EP_UPDATE_DISCONNECTED)
+  else()
+    get_property(update_disconnected DIRECTORY PROPERTY EP_UPDATE_DISCONNECTED)
+  endif()
+  if(update_disconnected)
+    set(update_dep skip-update)
+  else()
+    set(update_dep update)
+  endif()
+
   ExternalProject_Add_Step(${name} configure
     COMMAND ${cmd}
     WORKING_DIRECTORY ${binary_dir}
-    DEPENDEES update patch
+    DEPENDEES ${update_dep} patch
     DEPENDS ${file_deps}
     ${log}
     )