pkg-download: Make a shallow clone for git downloads

When downloading from git, we clone the whole repository and then only
use the latest commit.  That's a lot of redundant stuff.  So instead,
make a shallow clone.  Unfortunately that's only possible when
downloading a branch or tag, so fall back to the old method if git gives
an error.

This speeds up the cloning of a linux git from more than 2 hours to
20 minutes on a 200KB/s link).

Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>
Acked-by: Luca Ceresoli <luca@lucaceresoli.net>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>

diff --git a/package/pkg-download.mk b/package/pkg-download.mk
index fa9a3e88359d479ab6739bba4d4dde4ef2f6af47..6c57244ac6c2735f62a1366c9abc78a5d79af104 100644 (file)
--- a/package/pkg-download.mk
+++ b/package/pkg-download.mk
@@ -73,10 +73,13 @@ domainseparator=$(if $(1),$(1),/)
 # "external dependencies" of a given build configuration.
 ################################################################################
 
+# Try a shallow clone - but that only works if the version is a ref (tag or
+# branch). Fall back on a full clone if it's a generic sha1.
 define DOWNLOAD_GIT
        test -e $(DL_DIR)/$($(PKG)_SOURCE) || \
        (pushd $(DL_DIR) > /dev/null && \
-       $(GIT) clone --bare $($(PKG)_SITE) $($(PKG)_BASE_NAME) && \
+        ($(GIT) clone --depth 1 -b $($(PKG)_DL_VERSION) --bare $($(PKG)_SITE) $($(PKG)_BASE_NAME) || \
+         $(GIT) clone --bare $($(PKG)_SITE) $($(PKG)_BASE_NAME)) && \
        pushd $($(PKG)_BASE_NAME) > /dev/null && \
        $(GIT) archive --format=tar --prefix=$($(PKG)_BASE_NAME)/ $($(PKG)_DL_VERSION) | \
                gzip -c > $(DL_DIR)/$($(PKG)_SOURCE) && \