From 922697c8b27570b6c76a472266507b73f6b79f7f Mon Sep 17 00:00:00 2001
From: Eelco Dolstra <e.dolstra@tudelft.nl>
Date: Thu, 9 Mar 2006 15:09:18 +0000
Subject: * Big speedup (factor > 2.5) in all nix-env operations that do actual
   instantiation, e.g. "nix-env -i" and "nix-env -qas" (but not   "nix-env
 -qa").  It turns out that many redundant calls to   addToStore(path) were
 made, which reads and hashes the entire path.   For instance, the bash
 bootstrap binary in Nixpkgs would be read and   hashed many times.  As a
 result nix-env would spend around 92% of   its time in the function
 sha256_block (according to callgrind).   Some simple memoization fixes this.

---
 src/libexpr/eval.hh | 5 +++++
 1 file changed, 5 insertions(+)

(limited to 'src/libexpr/eval.hh')

diff --git a/src/libexpr/eval.hh b/src/libexpr/eval.hh
index 11185159c123..602f63fdedaf 100644
--- a/src/libexpr/eval.hh
+++ b/src/libexpr/eval.hh
@@ -11,6 +11,10 @@
 typedef map<Path, PathSet> DrvRoots;
 typedef map<Path, Hash> DrvHashes;
 
+/* Cache for calls to addToStore(); maps source paths to the store
+   paths. */
+typedef map<Path, Path> SrcToStore;
+
 struct EvalState;
 
 /* Note: using a ATermVector is safe here, since when we call a primop
@@ -24,6 +28,7 @@ struct EvalState
     ATermMap primOps;
     DrvRoots drvRoots;
     DrvHashes drvHashes; /* normalised derivation hashes */
+    SrcToStore srcToStore; 
     Expr blackHole;
 
     unsigned int nrEvaluated;
-- 
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