From 32c629f4ac95883cecdc99356792bda45933b674 Mon Sep 17 00:00:00 2001
From: Vladimir Prus <ghost@cs.msu.su>
Date: Tue, 20 Sep 2005 13:11:47 +0000
Subject: [PATCH] Optimize scanner construction. Instead of calling
 property.select on raw properties list for each file, use a cache keyed by
 property-set instance.

[SVN r31055]
---
 v2/build/scanner.jam | 18 +++++++++++-------
 v2/build/type.jam    |  2 +-
 2 files changed, 12 insertions(+), 8 deletions(-)

diff --git a/v2/build/scanner.jam b/v2/build/scanner.jam
index 10af04c07..b070f0fa5 100644
--- a/v2/build/scanner.jam
+++ b/v2/build/scanner.jam
@@ -27,7 +27,7 @@
 #  way, instead of relying on just target type.
 
 import "class" : new ;
-import property virtual-target ;
+import property virtual-target property-set ;
 
 #  Base scanner class. 
 class scanner 
@@ -87,21 +87,25 @@ class common-scanner : scanner
 
 # Returns an instance of previously registered scanner,
 # with the specified properties.
-rule get ( scanner-class : properties * ) 
+rule get ( scanner-class : property-set ) 
 {
     if ! $(scanner-class) in $(.registered)
     {
         error "attempt to get unregisted scanner" ;
     }
-    local r = [ property.select $(.relevant-properties.$(scanner-class)) :
-                $(properties) ] ;
+    
+    local r = $(.rv-cache.$(property-set)) ;
     if ! $(r)
     {
-        r = "" ;
-    }    
+        r = [ property-set.create 
+            [ property.select $(.relevant-properties.$(scanner-class)) :
+              [ $(property-set).raw ] ] ] ;        
+        .rv-cache.$(property-set) = $(r) ;
+    }
+        
     if ! $(scanner.$(scanner-class).$(r:J=-))
     {
-        scanner.$(scanner-class).$(r:J=-) = [ new $(scanner-class) $(r) ] ;
+        scanner.$(scanner-class).$(r:J=-) = [ new $(scanner-class) [ $(r).raw ] ] ;
     }
     return $(scanner.$(scanner-class).$(r:J=-)) ;    
 }
diff --git a/v2/build/type.jam b/v2/build/type.jam
index fb99a5f6c..fe193e5cf 100644
--- a/v2/build/type.jam
+++ b/v2/build/type.jam
@@ -156,7 +156,7 @@ rule set-scanner ( type : scanner )
 rule get-scanner ( type : property-set )
 {
     if $(.scanner.$(type)) {
-        return [ scanner.get $(.scanner.$(type)) : [ $(property-set).raw ] ] ;
+        return [ scanner.get $(.scanner.$(type)) : $(property-set) ] ;
     }    
 }