[PATCH 1/4] rev-list: refactor --missing=<missing-action>

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

Both `git rev-list` and `git pack-objects` support a
`--missing=<missing-action>` feature, but they currently don't share
any code for that.

In a following commit, we are going to add support for a similar
'missing-action' feature to another command. To avoid duplicating
similar code, let's start refactoring the rev-list code for this
feature into new "missing.{c,h}" files.

For now, this refactoring is about moving code from
"builtin/rev-list.c" into new "missing.{c,h}" files. But in a
following commit, that refactored code will be used in
`git pack-objects` too.

As `enum missing_action` and parse_missing_action_value() are moved to
"missing.{c,h}", we need to modify the later a bit, so that it stops
updating a global variable, but instead returns either -1 on error or
the parsed value otherwise.

Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
---
 Makefile           |  1 +
 builtin/rev-list.c | 41 ++++++-----------------------------------
 missing.c          | 26 ++++++++++++++++++++++++++
 missing.h          | 18 ++++++++++++++++++
 4 files changed, 51 insertions(+), 35 deletions(-)
 create mode 100644 missing.c
 create mode 100644 missing.h

diff --git a/Makefile b/Makefile
index 1e31acc72e..75583a71a0 100644
--- a/Makefile
+++ b/Makefile
@@ -1076,6 +1076,7 @@ LIB_OBJS += merge-recursive.o
 LIB_OBJS += merge.o
 LIB_OBJS += midx.o
 LIB_OBJS += midx-write.o
+LIB_OBJS += missing.o
 LIB_OBJS += name-hash.o
 LIB_OBJS += negotiator/default.o
 LIB_OBJS += negotiator/noop.o
diff --git a/builtin/rev-list.c b/builtin/rev-list.c
index 77803727e0..f71cc5ebe1 100644
--- a/builtin/rev-list.c
+++ b/builtin/rev-list.c
@@ -20,6 +20,7 @@
 #include "reflog-walk.h"
 #include "oidset.h"
 #include "packfile.h"
+#include "missing.h"
 
 static const char rev_list_usage[] =
 "git rev-list [<options>] <commit>... [--] [<path>...]\n"
@@ -71,12 +72,6 @@ static struct oidset omitted_objects;
 static int arg_print_omitted; /* print objects omitted by filter */
 
 static struct oidset missing_objects;
-enum missing_action {
-	MA_ERROR = 0,    /* fail if any missing objects are encountered */
-	MA_ALLOW_ANY,    /* silently allow ALL missing objects */
-	MA_PRINT,        /* print ALL missing objects in special section */
-	MA_ALLOW_PROMISOR, /* silently allow all missing PROMISOR objects */
-};
 static enum missing_action arg_missing_action;
 
 /* display only the oid of each object encountered */
@@ -392,34 +387,6 @@ static void print_disk_usage(off_t size)
 	strbuf_release(&sb);
 }
 
-static inline int parse_missing_action_value(const char *value)
-{
-	if (!strcmp(value, "error")) {
-		arg_missing_action = MA_ERROR;
-		return 1;
-	}
-
-	if (!strcmp(value, "allow-any")) {
-		arg_missing_action = MA_ALLOW_ANY;
-		fetch_if_missing = 0;
-		return 1;
-	}
-
-	if (!strcmp(value, "print")) {
-		arg_missing_action = MA_PRINT;
-		fetch_if_missing = 0;
-		return 1;
-	}
-
-	if (!strcmp(value, "allow-promisor")) {
-		arg_missing_action = MA_ALLOW_PROMISOR;
-		fetch_if_missing = 0;
-		return 1;
-	}
-
-	return 0;
-}
-
 static int try_bitmap_count(struct rev_info *revs,
 			    int filter_provided_objects)
 {
@@ -569,10 +536,14 @@ int cmd_rev_list(int argc, const char **argv, const char *prefix)
 	for (i = 1; i < argc; i++) {
 		const char *arg = argv[i];
 		if (skip_prefix(arg, "--missing=", &arg)) {
+			int res;
 			if (revs.exclude_promisor_objects)
 				die(_("options '%s' and '%s' cannot be used together"), "--exclude-promisor-objects", "--missing");
-			if (parse_missing_action_value(arg))
+			res = parse_missing_action_value(arg);
+			if (res >= 0) {
+				arg_missing_action = res;
 				break;
+			}
 		}
 	}
 
diff --git a/missing.c b/missing.c
new file mode 100644
index 0000000000..83e0c5e584
--- /dev/null
+++ b/missing.c
@@ -0,0 +1,26 @@
+#include "git-compat-util.h"
+#include "missing.h"
+#include "object-file.h"
+
+int parse_missing_action_value(const char *value)
+{
+	if (!strcmp(value, "error"))
+		return MA_ERROR;
+
+	if (!strcmp(value, "allow-any")) {
+		fetch_if_missing = 0;
+		return MA_ALLOW_ANY;
+	}
+
+	if (!strcmp(value, "print")) {
+		fetch_if_missing = 0;
+		return MA_PRINT;
+	}
+
+	if (!strcmp(value, "allow-promisor")) {
+		fetch_if_missing = 0;
+		return MA_ALLOW_PROMISOR;
+	}
+
+	return -1;
+}
diff --git a/missing.h b/missing.h
new file mode 100644
index 0000000000..c8261dfe55
--- /dev/null
+++ b/missing.h
@@ -0,0 +1,18 @@
+#ifndef MISSING_H
+#define MISSING_H
+
+enum missing_action {
+	MA_ERROR = 0,    /* fail if any missing objects are encountered */
+	MA_ALLOW_ANY,    /* silently allow ALL missing objects */
+	MA_PRINT,        /* print ALL missing objects in special section */
+	MA_ALLOW_PROMISOR, /* silently allow all missing PROMISOR objects */
+};
+
+/*
+  Return an `enum missing_action` in case parsing is successful or -1
+  if parsing failed. Also sets the fetch_if_missing global variable
+  from "object-file.h".
+ */
+int parse_missing_action_value(const char *value);
+
+#endif /* MISSING_H */
-- 
2.44.0.655.g111bceeb19