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* Allow an optional hash to be provided. This prevents redundant

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fetches.
This commit is contained in:
Eelco Dolstra 2004-12-13 13:35:36 +00:00
parent 71926ee188
commit dca48aed34
1 changed files with 26 additions and 20 deletions
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16
scripts/nix-prefetch-url.in
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@ -1,18 +1,22 @@
#! @shell@ -e #! @shell@ -e
url=$1 url=$1
hash=$2
if test -z "$url"; then if test -z "$url"; then
echo "syntax: nix-prefetch-url URL" >&2 echo "syntax: nix-prefetch-url URL" >&2
exit 1 exit 1
fi fi
# Determine the hash, unless it was given.
if test -z "$hash"; then
# !!! race # !!! race
tmpPath1=@storedir@/nix-prefetch-url-$$ tmpPath1=@storedir@/nix-prefetch-url-$$
# Test whether we have write permission in the store. If not, fetch # Test whether we have write permission in the store. If not,
# to /tmp and don't copy to the store. This is a hack to make this # fetch to /tmp and don't copy to the store. This is a hack to
# script at least work somewhat in setuid installations. # make this script at least work somewhat in setuid installations.
if ! touch $tmpPath1 2> /dev/null; then if ! touch $tmpPath1 2> /dev/null; then
echo "(cannot write to the store, result won't be cached)" >&2 echo "(cannot write to the store, result won't be cached)" >&2
dummyMode=1 dummyMode=1
@ -24,7 +28,7 @@ fi
# Compute the hash. # Compute the hash.
hash=$(@bindir@/nix-hash --flat $tmpPath1) hash=$(@bindir@/nix-hash --flat $tmpPath1)
echo "hash is $hash" >&2 if ! test -n "$QUIET"; then echo "hash is $hash" >&2; fi
# Rename it so that the fetchurl builder can find it. # Rename it so that the fetchurl builder can find it.
if test "$dummyMode" != 1; then if test "$dummyMode" != 1; then
@ -32,6 +36,8 @@ if test "$dummyMode" != 1; then
test -e $tmpPath2 || mv $tmpPath1 $tmpPath2 # !!! race test -e $tmpPath2 || mv $tmpPath1 $tmpPath2 # !!! race
fi fi
fi
# Create a Nix expression that does a fetchurl. # Create a Nix expression that does a fetchurl.
storeExpr=$( \ storeExpr=$( \
echo "(import @datadir@/nix/corepkgs/fetchurl) \ echo "(import @datadir@/nix/corepkgs/fetchurl) \
@ -41,7 +47,7 @@ storeExpr=$( \
# Realise it. # Realise it.
finalPath=$(@bindir@/nix-store -qnB --force-realise $storeExpr) finalPath=$(@bindir@/nix-store -qnB --force-realise $storeExpr)
echo "path is $finalPath" >&2 if ! test -n "$QUIET"; then echo "path is $finalPath" >&2; fi
rm -rf $tmpPath1 $tmpPath2 || true rm -rf $tmpPath1 $tmpPath2 || true