credentials: add "cache" helper

If you access repositories over smart-http using http
authentication, then it can be annoying to have git ask you
for your password repeatedly. We cache credentials in
memory, of course, but git is composed of many small
programs. Having to input your password for each one can be
frustrating.

This patch introduces a credential helper that will cache
passwords in memory for a short period of time.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

2 files changed, 239 insertions, 0 deletions

diff --git a/t/lib-credential.sh b/t/lib-credential.sh
index 54ae1f484c..4a37cd79e5 100755
--- a/t/lib-credential.sh
+++ b/t/lib-credential.sh
@@ -21,6 +21,227 @@ read_chunk() {
 	done
 }
 
+# Clear any residual data from previous tests. We only
+# need this when testing third-party helpers which read and
+# write outside of our trash-directory sandbox.
+#
+# Don't bother checking for success here, as it is
+# outside the scope of tests and represents a best effort to
+# clean up after ourselves.
+helper_test_clean() {
+	reject $1 https example.com store-user
+	reject $1 https example.com user1
+	reject $1 https example.com user2
+	reject $1 http path.tld user
+	reject $1 https timeout.tld user
+}
+
+reject() {
+	(
+		echo protocol=$2
+		echo host=$3
+		echo username=$4
+	) | test-credential reject $1
+}
+
+helper_test() {
+	HELPER=$1
+
+	test_expect_success "helper ($HELPER) has no existing data" '
+		check fill $HELPER <<-\EOF
+		protocol=https
+		host=example.com
+		--
+		username=askpass-username
+		password=askpass-password
+		--
+		askpass: Username for '\''https://example.com'\'':
+		askpass: Password for '\''https://askpass-username@example.com'\'':
+		EOF
+	'
+
+	test_expect_success "helper ($HELPER) stores password" '
+		check approve $HELPER <<-\EOF
+		protocol=https
+		host=example.com
+		username=store-user
+		password=store-pass
+		EOF
+	'
+
+	test_expect_success "helper ($HELPER) can retrieve password" '
+		check fill $HELPER <<-\EOF
+		protocol=https
+		host=example.com
+		--
+		username=store-user
+		password=store-pass
+		--
+		EOF
+	'
+
+	test_expect_success "helper ($HELPER) requires matching protocol" '
+		check fill $HELPER <<-\EOF
+		protocol=http
+		host=example.com
+		--
+		username=askpass-username
+		password=askpass-password
+		--
+		askpass: Username for '\''http://example.com'\'':
+		askpass: Password for '\''http://askpass-username@example.com'\'':
+		EOF
+	'
+
+	test_expect_success "helper ($HELPER) requires matching host" '
+		check fill $HELPER <<-\EOF
+		protocol=https
+		host=other.tld
+		--
+		username=askpass-username
+		password=askpass-password
+		--
+		askpass: Username for '\''https://other.tld'\'':
+		askpass: Password for '\''https://askpass-username@other.tld'\'':
+		EOF
+	'
+
+	test_expect_success "helper ($HELPER) requires matching username" '
+		check fill $HELPER <<-\EOF
+		protocol=https
+		host=example.com
+		username=other
+		--
+		username=other
+		password=askpass-password
+		--
+		askpass: Password for '\''https://other@example.com'\'':
+		EOF
+	'
+
+	test_expect_success "helper ($HELPER) requires matching path" '
+		test_config credential.usehttppath true &&
+		check approve $HELPER <<-\EOF &&
+		protocol=http
+		host=path.tld
+		path=foo.git
+		username=user
+		password=pass
+		EOF
+		check fill $HELPER <<-\EOF
+		protocol=http
+		host=path.tld
+		path=bar.git
+		--
+		username=askpass-username
+		password=askpass-password
+		--
+		askpass: Username for '\''http://path.tld/bar.git'\'':
+		askpass: Password for '\''http://askpass-username@path.tld/bar.git'\'':
+		EOF
+	'
+
+	test_expect_success "helper ($HELPER) can forget host" '
+		check reject $HELPER <<-\EOF &&
+		protocol=https
+		host=example.com
+		EOF
+		check fill $HELPER <<-\EOF
+		protocol=https
+		host=example.com
+		--
+		username=askpass-username
+		password=askpass-password
+		--
+		askpass: Username for '\''https://example.com'\'':
+		askpass: Password for '\''https://askpass-username@example.com'\'':
+		EOF
+	'
+
+	test_expect_success "helper ($HELPER) can store multiple users" '
+		check approve $HELPER <<-\EOF &&
+		protocol=https
+		host=example.com
+		username=user1
+		password=pass1
+		EOF
+		check approve $HELPER <<-\EOF &&
+		protocol=https
+		host=example.com
+		username=user2
+		password=pass2
+		EOF
+		check fill $HELPER <<-\EOF &&
+		protocol=https
+		host=example.com
+		username=user1
+		--
+		username=user1
+		password=pass1
+		EOF
+		check fill $HELPER <<-\EOF
+		protocol=https
+		host=example.com
+		username=user2
+		--
+		username=user2
+		password=pass2
+		EOF
+	'
+
+	test_expect_success "helper ($HELPER) can forget user" '
+		check reject $HELPER <<-\EOF &&
+		protocol=https
+		host=example.com
+		username=user1
+		EOF
+		check fill $HELPER <<-\EOF
+		protocol=https
+		host=example.com
+		username=user1
+		--
+		username=user1
+		password=askpass-password
+		--
+		askpass: Password for '\''https://user1@example.com'\'':
+		EOF
+	'
+
+	test_expect_success "helper ($HELPER) remembers other user" '
+		check fill $HELPER <<-\EOF
+		protocol=https
+		host=example.com
+		username=user2
+		--
+		username=user2
+		password=pass2
+		EOF
+	'
+}
+
+helper_test_timeout() {
+	HELPER="$*"
+
+	test_expect_success "helper ($HELPER) times out" '
+		check approve "$HELPER" <<-\EOF &&
+		protocol=https
+		host=timeout.tld
+		username=user
+		password=pass
+		EOF
+		sleep 2 &&
+		check fill "$HELPER" <<-\EOF
+		protocol=https
+		host=timeout.tld
+		--
+		username=askpass-username
+		password=askpass-password
+		--
+		askpass: Username for '\''https://timeout.tld'\'':
+		askpass: Password for '\''https://askpass-username@timeout.tld'\'':
+		EOF
+	'
+}
 
 cat >askpass <<\EOF
 #!/bin/sh
diff --git a/t/t0301-credential-cache.sh b/t/t0301-credential-cache.sh
new file mode 100755
index 0000000000..3a65f99531
--- /dev/null
+++ b/t/t0301-credential-cache.sh
@@ -0,0 +1,18 @@
+#!/bin/sh
+
+test_description='credential-cache tests'
+. ./test-lib.sh
+. "$TEST_DIRECTORY"/lib-credential.sh
+
+# don't leave a stale daemon running
+trap 'code=$?; git credential-cache exit; (exit $code); die' EXIT
+
+helper_test cache
+helper_test_timeout cache --timeout=1
+
+# we can't rely on our "trap" above working after test_done,
+# as test_done will delete the trash directory containing
+# our socket, leaving us with no way to access the daemon.
+git credential-cache exit
+
+test_done