From 067da47ef2483324946f44272c6a968b2aac2ea7 Mon Sep 17 00:00:00 2001
From: Steven Knight <knight@baldmt.com>
Date: Thu, 3 Jan 2002 17:41:32 +0000
Subject: Signature performance improvements (Charles Crain).

---
 src/CHANGES.txt                  |  4 ++++
 src/engine/SCons/Sig/SigTests.py | 16 ++++++++++++++--
 src/engine/SCons/Sig/__init__.py | 19 ++++++++++++++++++-
 3 files changed, 36 insertions(+), 3 deletions(-)

diff --git a/src/CHANGES.txt b/src/CHANGES.txt
index 45e5f2b..fc04479 100644
--- a/src/CHANGES.txt
+++ b/src/CHANGES.txt
@@ -10,6 +10,10 @@
 
 RELEASE 0.03 - 
 
+  From Charles Crain:
+
+  - Performance improvements in the Node.FS and Sig.Calculator classes.
+
   From Steven Knight:
 
   - Search both /usr/lib and /usr/local/lib for scons directories by
diff --git a/src/engine/SCons/Sig/SigTests.py b/src/engine/SCons/Sig/SigTests.py
index 19816d5..148fc9a 100644
--- a/src/engine/SCons/Sig/SigTests.py
+++ b/src/engine/SCons/Sig/SigTests.py
@@ -91,7 +91,7 @@ class DummyNode:
         self.csig = csig
 
     def get_csig(self):
-        return self.bsig
+        return self.csig
 
     def get_prevsiginfo(self):
         return (self.oldtime, self.oldbsig, self.oldcsig)
@@ -162,6 +162,7 @@ class SigTestBase:
         self.test_built()
         self.test_modify()
         self.test_delete()
+        self.test_cache()
         
     def test_initial(self):
         
@@ -240,7 +241,18 @@ class SigTestBase:
         self.failUnless(current(calc, nodes[8]))
         self.failUnless(not current(calc, nodes[9]), "deleted")
         self.failUnless(current(calc, nodes[10]),
-                        "current even though its source was deleted") 
+                        "current even though its source was deleted")
+
+    def test_cache(self):
+        """Test that signatures are cached properly."""
+        nodes = create_nodes(self.files)
+        
+        calc = SCons.Sig.Calculator(self.module)
+        nodes[0].set_csig(1)
+        nodes[1].set_bsig(1)
+        assert calc.csig(nodes[0]) == 1, calc.csig(nodes[0])
+        assert calc.bsig(nodes[1]) == 1, calc.bsig(nodes[1])
+        
 
 class MD5TestCase(unittest.TestCase, SigTestBase):
     """Test MD5 signatures"""
diff --git a/src/engine/SCons/Sig/__init__.py b/src/engine/SCons/Sig/__init__.py
index 22ec2e9..25e0d2f 100644
--- a/src/engine/SCons/Sig/__init__.py
+++ b/src/engine/SCons/Sig/__init__.py
@@ -159,6 +159,10 @@ class Calculator:
         #XXX If configured, use the content signatures from the
         #XXX .sconsign file if the timestamps match.
 
+        bsig = node.get_bsig()
+        if not bsig is None:
+            return bsig
+
         # Collect the signatures for ALL the nodes that this
         # node depends on. Just collecting the direct
         # dependants is not good enough, because
@@ -166,7 +170,16 @@ class Calculator:
         # not include the signatures of its psuedo-sources
         # (e.g. the signature for a .c file does not include
         # the signatures of the .h files that it includes).
-        walker = SCons.Node.Walker(node)
+
+        # However, we do NOT want to walk dependencies of non-
+        # derived files, because calling get_signature() on the
+        # derived nodes will in turn call bsig() again and do that
+        # for us.  Hence:
+        def walk_non_derived(n, myself=node):
+            if not n.builder or n is myself:
+                return n.children()
+            return []
+        walker = SCons.Node.Walker(node, walk_non_derived)
         sigs = []
         while 1:
             child = walker.next()
@@ -190,6 +203,10 @@ class Calculator:
             return None
         #XXX If configured, use the content signatures from the
         #XXX .sconsign file if the timestamps match.
+        csig = node.get_csig()
+        if not csig is None:
+            return csig
+        
         return self.module.signature(node)
 
     def get_signature(self, node):
-- 
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