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authorLudovic Courtès <ludo@gnu.org>2013-09-02 23:03:03 +0200
committerLudovic Courtès <ludo@gnu.org>2013-09-02 23:04:25 +0200
commit43dd92024ab54921fbf85285d04344cb2c6e77cc (patch)
tree802ce4e8c2eab83358c0f1cd95373bd49ec76440
parent165fd9d5e628120a8355aec2d03f0b6f497d3db2 (diff)
downloadpatches-43dd92024ab54921fbf85285d04344cb2c6e77cc.tar
patches-43dd92024ab54921fbf85285d04344cb2c6e77cc.tar.gz
union: Don't traverse sub-directories only found in one element of the union.
This significantly reduces I/O when building profiles, especially with lots of package-specific sub-directories (such as 'share/emacs/24.3', 'texmf', etc.) * guix/build/union.scm (union-build)[file-tree](others-have-it?): New procedure. Use it in the 'enter?' parameter of 'file-system-fold'; change 'skip' parameter accordingly. * tests/union.scm ("union-build"): Ensure that 'include' is a symlink and 'bin' is a directory.
-rw-r--r--guix/build/union.scm29
-rw-r--r--tests/union.scm12
2 files changed, 36 insertions, 5 deletions
diff --git a/guix/build/union.scm b/guix/build/union.scm
index 275746d83e..077b7fe530 100644
--- a/guix/build/union.scm
+++ b/guix/build/union.scm
@@ -105,7 +105,22 @@ single leaf."
the DIRECTORIES."
(define (file-tree dir)
;; Return the contents of DIR as a tree.
- (match (file-system-fold (const #t)
+
+ (define (others-have-it? subdir)
+ ;; Return #t if other elements of DIRECTORIES have SUBDIR.
+ (let ((subdir (substring subdir (string-length dir))))
+ (any (lambda (other)
+ (and (not (string=? other dir))
+ (file-exists? (string-append other "/" subdir))))
+ directories)))
+
+ (match (file-system-fold (lambda (subdir stat result) ; enter?
+ ;; No need to traverse DIR since there's
+ ;; nothing to union it with. Thus, we avoid
+ ;; creating a gazillon symlinks (think
+ ;; share/emacs/24.3, share/texmf, etc.)
+ (or (string=? subdir dir)
+ (others-have-it? subdir)))
(lambda (file stat result) ; leaf
(match result
(((siblings ...) rest ...)
@@ -117,7 +132,12 @@ the DIRECTORIES."
(((leaves ...) (siblings ...) rest ...)
`(((,(basename dir) ,@leaves) ,@siblings)
,@rest))))
- (const #f) ; skip
+ (lambda (dir stat result) ; skip
+ ;; DIR is not available elsewhere, so treat it
+ ;; as a leaf.
+ (match result
+ (((siblings ...) rest ...)
+ `((,dir ,@siblings) ,@rest))))
(lambda (file stat errno result)
(format (current-error-port) "union-build: ~a: ~a~%"
file (strerror errno)))
@@ -158,8 +178,9 @@ the DIRECTORIES."
(mkdir output)
(let loop ((tree (delete-duplicate-leaves
(cons "."
- (tree-union (append-map (compose tree-leaves file-tree)
- directories)))
+ (tree-union
+ (append-map (compose tree-leaves file-tree)
+ (delete-duplicates directories))))
leaf=?
resolve-collision))
(dir '()))
diff --git a/tests/union.scm b/tests/union.scm
index 9816882101..6287cffc38 100644
--- a/tests/union.scm
+++ b/tests/union.scm
@@ -114,7 +114,17 @@
(file-exists? "bin/ld")
(file-exists? "lib/libc.so")
(directory-exists? "lib/gcc")
- (file-exists? "include/unistd.h"))))))
+ (file-exists? "include/unistd.h")
+
+ ;; The 'include' sub-directory is only found in
+ ;; glibc-bootstrap, so it should be unified in a
+ ;; straightforward way, without traversing it.
+ (eq? 'symlink (stat:type (lstat "include")))
+
+ ;; Conversely, several inputs have a 'bin' sub-directory, so
+ ;; unifying it requires traversing them all, and creating a
+ ;; new 'bin' sub-directory in the profile.
+ (eq? 'directory (stat:type (lstat "bin"))))))))
(test-end)