[RFC/PATCH v4 24/49] odb-helper: start fault in implementation

[Christian Couder <christian.couder@gmail.com>]

Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
---
 external-odb.c                 | 24 ++++++++++++++++++++++--
 odb-helper.c                   | 30 ++++++++++++++++++++++++++++--
 odb-helper.h                   |  8 +++++++-
 t/t0400-external-odb.sh        |  2 ++
 t/t0410-transfer-e-odb.sh      |  4 +++-
 t/t0420-transfer-http-e-odb.sh |  6 +++---
 6 files changed, 65 insertions(+), 9 deletions(-)

diff --git a/external-odb.c b/external-odb.c
index d11fc98719..0b6e443372 100644
--- a/external-odb.c
+++ b/external-odb.c
@@ -20,6 +20,19 @@ static struct odb_helper *find_or_create_helper(const char *name, int len)
 	return o;
 }
 
+static enum odb_helper_fetch_kind parse_fetch_kind(const char *key,
+						   const char *value)
+{
+	if (!strcasecmp(value, "plainobject"))
+		return ODB_FETCH_KIND_PLAIN_OBJECT;
+	else if (!strcasecmp(value, "gitobject"))
+		return ODB_FETCH_KIND_GIT_OBJECT;
+	else if (!strcasecmp(value, "faultin"))
+		return ODB_FETCH_KIND_FAULT_IN;
+
+	die("unknown value for config '%s': %s", key, value);
+}
+
 static int external_odb_config(const char *var, const char *value, void *data)
 {
 	struct odb_helper *o;
@@ -36,8 +49,15 @@ static int external_odb_config(const char *var, const char *value, void *data)
 
 	if (!strcmp(key, "command"))
 		return git_config_string(&o->cmd, var, value);
-	if (!strcmp(key, "plainobjects"))
-		o->store_plain_objects = git_config_bool(var, value);
+	if (!strcmp(key, "fetchkind")) {
+		const char *fetch_kind;
+		int ret = git_config_string(&fetch_kind, var, value);
+		if (!ret) {
+			o->fetch_kind = parse_fetch_kind(var, fetch_kind);
+			free((char *)fetch_kind);
+		}
+		return ret;
+	}
 
 	return 0;
 }
diff --git a/odb-helper.c b/odb-helper.c
index b33ee81c97..24dc5375cb 100644
--- a/odb-helper.c
+++ b/odb-helper.c
@@ -347,14 +347,40 @@ static int odb_helper_fetch_git_object(struct odb_helper *o,
 	return 0;
 }
 
+static int odb_helper_fetch_fault_in(struct odb_helper *o,
+				     const unsigned char *sha1,
+				     int fd)
+{
+	struct odb_helper_object *obj;
+	struct odb_helper_cmd cmd;
+
+	obj = odb_helper_lookup(o, sha1);
+	if (!obj)
+		return -1;
+
+	if (odb_helper_start(o, &cmd, 0, "get %s", sha1_to_hex(sha1)) < 0)
+		return -1;
+
+	if (odb_helper_finish(o, &cmd))
+		return -1;
+
+	return 0;
+}
+
 int odb_helper_fetch_object(struct odb_helper *o,
 			    const unsigned char *sha1,
 			    int fd)
 {
-	if (o->store_plain_objects)
+	switch(o->fetch_kind) {
+	case ODB_FETCH_KIND_PLAIN_OBJECT:
 		return odb_helper_fetch_plain_object(o, sha1, fd);
-	else
+	case ODB_FETCH_KIND_GIT_OBJECT:
 		return odb_helper_fetch_git_object(o, sha1, fd);
+	case ODB_FETCH_KIND_FAULT_IN:
+		return odb_helper_fetch_fault_in(o, sha1, fd);
+	default:
+		BUG("invalid fetch kind '%d'", o->fetch_kind);
+	}
 }
 
 int odb_helper_for_each_object(struct odb_helper *o,
diff --git a/odb-helper.h b/odb-helper.h
index 3953b9bbaf..e3ad8e3316 100644
--- a/odb-helper.h
+++ b/odb-helper.h
@@ -3,10 +3,16 @@
 
 #include "external-odb.h"
 
+enum odb_helper_fetch_kind {
+	ODB_FETCH_KIND_PLAIN_OBJECT = 0,
+	ODB_FETCH_KIND_GIT_OBJECT,
+	ODB_FETCH_KIND_FAULT_IN
+};
+
 struct odb_helper {
 	const char *name;
 	const char *cmd;
-	int store_plain_objects;
+	enum odb_helper_fetch_kind fetch_kind;
 
 	struct odb_helper_object {
 		unsigned char sha1[20];
diff --git a/t/t0400-external-odb.sh b/t/t0400-external-odb.sh
index 3c868cad4c..c3cb0fdc84 100755
--- a/t/t0400-external-odb.sh
+++ b/t/t0400-external-odb.sh
@@ -49,6 +49,7 @@ test_expect_success 'alt objects are missing' '
 
 test_expect_success 'helper can retrieve alt objects' '
 	test_config odb.magic.command "$HELPER" &&
+	test_config odb.magic.fetchKind "gitObject" &&
 	cat >expect <<-\EOF &&
 	two
 	one
@@ -68,6 +69,7 @@ test_expect_success 'helper can add objects to alt repo' '
 
 test_expect_success 'commit adds objects to alt repo' '
 	test_config odb.magic.command "$HELPER" &&
+	test_config odb.magic.fetchKind "gitObject" &&
 	test_commit three &&
 	hash3=$(git ls-tree HEAD | grep three.t | cut -f1 | cut -d\  -f3) &&
 	content=$(cd alt-repo && git show "$hash3") &&
diff --git a/t/t0410-transfer-e-odb.sh b/t/t0410-transfer-e-odb.sh
index 868b55db94..cba89866e2 100755
--- a/t/t0410-transfer-e-odb.sh
+++ b/t/t0410-transfer-e-odb.sh
@@ -89,7 +89,8 @@ HELPER2="\"$PWD\"/odb-helper2"
 test_expect_success 'setup first alternate repo' '
 	git init alt-repo1 &&
 	test_commit zero &&
-	git config odb.magic.command "$HELPER1"
+	git config odb.magic.command "$HELPER1" &&
+	git config odb.magic.fetchKind "gitObject"
 '
 
 test_expect_success 'setup other repo and its alternate repo' '
@@ -119,6 +120,7 @@ test_expect_success 'other repo gets the blobs from object store' '
 	 test_must_fail git cat-file blob "$hash1" &&
 	 test_must_fail git cat-file blob "$hash2" &&
 	 git config odb.magic.command "$HELPER2" &&
+	 git config odb.magic.fetchKind "gitObject"
 	 git cat-file blob "$hash1" &&
 	 git cat-file blob "$hash2"
 	)
diff --git a/t/t0420-transfer-http-e-odb.sh b/t/t0420-transfer-http-e-odb.sh
index 716d722e97..8a5f3adaa7 100755
--- a/t/t0420-transfer-http-e-odb.sh
+++ b/t/t0420-transfer-http-e-odb.sh
@@ -53,7 +53,7 @@ HELPER="\"$PWD\"/odb-http-helper"
 test_expect_success 'setup repo with a root commit and the helper' '
 	test_commit zero &&
 	git config odb.magic.command "$HELPER" &&
-	git config odb.magic.plainObjects "true"
+	git config odb.magic.fetchKind "plainObject"
 '
 
 test_expect_success 'setup another repo from the first one' '
@@ -108,7 +108,7 @@ test_expect_success 'update other repo from the first one' '
 	 git fetch origin "refs/odbs/magic/*:refs/odbs/magic/*" &&
 	 test_must_fail git cat-file blob "$hash1" &&
 	 git config odb.magic.command "$HELPER" &&
-	 git config odb.magic.plainObjects "true" &&
+	 git config odb.magic.fetchKind "plainObject" &&
 	 git cat-file blob "$hash1" &&
 	 git pull origin master)
 '
@@ -140,7 +140,7 @@ test_expect_success 'no-local initial-refspec clone succeeds' '
 	mkdir my-other-clone &&
 	(cd my-other-clone &&
 	 git config odb.magic.command "$HELPER" &&
-	 git config odb.magic.plainObjects "true" &&
+	 git config odb.magic.fetchKind "plainObject" &&
 	 git -c odb.magic.command="$HELPER" -c odb.magic.plainObjects="true" \
 		clone --no-local --initial-refspec "refs/odbs/magic/*:refs/odbs/magic/*" .. .)
 '
-- 
2.13.1.565.gbfcd7a9048