Extract hack to force recompilation if arguments change

1 files changed, 54 insertions, 1 deletions

diff --git a/jam-files/sanity.jam b/jam-files/sanity.jam
index 8c9715ac0..1080f9f3d 100644
--- a/jam-files/sanity.jam
+++ b/jam-files/sanity.jam
@@ -3,6 +3,7 @@ import option ;
 import os ;
 import path ;
 import project ;
+import build-system ;
 
 #Shell with trailing line removed http://lists.boost.org/boost-build/2007/08/17051.php
 rule trim-nl ( str extras * ) {
@@ -186,7 +187,59 @@ rule install-headers ( name : list * : source-root ? ) {
 }
 
 rule build-projects ( projects * ) {
-  for p in $(projects) {
+  for local p in $(projects) {
     build-project $(p) ;
   }
 }
+
+#Only one post build hook is allowed.  Allow multiple.  
+post-hooks = ;
+rule post-build ( ok ? ) {
+  for local r in $(post-hooks) {
+    $(r) $(ok) ;
+  }
+}
+IMPORT $(__name__) : post-build : : $(__name__).post-build ;
+build-system.set-post-build-hook $(__name__).post-build ;
+rule add-post-hook ( names * ) {
+  post-hooks += $(names) ;
+}
+
+
+#Backend for writing content to files after build completes.
+post-files = ;
+post-contents = ;
+rule save-post-build ( ok ? ) {
+  if $(ok) {
+    while $(post-files) {
+      local ignored = @($(post-files[1]):E=$(post-contents[1])) ;
+      post-files = $(post-files[2-]) ;
+      post-contents = $(post-contents[2-]) ;
+    }
+  }
+}
+add-post-hook save-post-build ;
+
+#Queue content to be written to file when build completes successfully.  
+rule add-post-write ( name content ) {
+  post-files += $(name) ;
+  post-contents += $(content) ;
+}
+
+#Compare contents of file with current.  If they're different, force the targets to rebuild then overwrite the file.  
+rule always-if-changed ( file current : targets * ) {
+  local previous = inconsistent ;
+  if [ path.exists $(file) ] {
+    previous = [ _shell "cat $(file)" ] ;
+  }
+  if $(current) != $(previous) {
+    #Write inconsistent while the build is running
+    if [ path.exists $(file) ] {
+      local ignored = @($(file):E=inconsistent) ;
+    }
+    add-post-write $(file) $(current) ;
+    for local i in $(targets) {
+      always $(i) ;
+    }
+  }
+}