[PATCH v6 3/6] grep: add submodules as a grep source type

[Brandon Williams]

Add `GREP_SOURCE_SUBMODULE` as a grep_source type and cases for this new
type in the various switch statements in grep.c.

When initializing a grep_source with type `GREP_SOURCE_SUBMODULE` the
identifier can either be NULL (to indicate that the working tree will be
used) or a SHA1 (the REV of the submodule to be grep'd).  If the
identifier is a SHA1 then we want to fall through to the
`GREP_SOURCE_SHA1` case to handle the copying of the SHA1.

Signed-off-by: Brandon Williams <bmw...@google.com>
---
 grep.c | 16 +++++++++++++++-
 grep.h |  1 +
 2 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/grep.c b/grep.c
index 1194d35..0dbdc1d 100644
--- a/grep.c
+++ b/grep.c
@@ -1735,12 +1735,23 @@ void grep_source_init(struct grep_source *gs, enum 
grep_source_type type,
        case GREP_SOURCE_FILE:
                gs->identifier = xstrdup(identifier);
                break;
+       case GREP_SOURCE_SUBMODULE:
+               if (!identifier) {
+                       gs->identifier = NULL;
+                       break;
+               }
+               /*
+                * FALL THROUGH
+                * If the identifier is non-NULL (in the submodule case) it
+                * will be a SHA1 that needs to be copied.
+                */
        case GREP_SOURCE_SHA1:
                gs->identifier = xmalloc(20);
                hashcpy(gs->identifier, identifier);
                break;
        case GREP_SOURCE_BUF:
                gs->identifier = NULL;
+               break;
        }
 }
 
@@ -1760,6 +1771,7 @@ void grep_source_clear_data(struct grep_source *gs)
        switch (gs->type) {
        case GREP_SOURCE_FILE:
        case GREP_SOURCE_SHA1:
+       case GREP_SOURCE_SUBMODULE:
                free(gs->buf);
                gs->buf = NULL;
                gs->size = 0;
@@ -1831,8 +1843,10 @@ static int grep_source_load(struct grep_source *gs)
                return grep_source_load_sha1(gs);
        case GREP_SOURCE_BUF:
                return gs->buf ? 0 : -1;
+       case GREP_SOURCE_SUBMODULE:
+               break;
        }
-       die("BUG: invalid grep_source type");
+       die("BUG: invalid grep_source type to load");
 }
 
 void grep_source_load_driver(struct grep_source *gs)
diff --git a/grep.h b/grep.h
index 5856a23..267534c 100644
--- a/grep.h
+++ b/grep.h
@@ -161,6 +161,7 @@ struct grep_source {
                GREP_SOURCE_SHA1,
                GREP_SOURCE_FILE,
                GREP_SOURCE_BUF,
+               GREP_SOURCE_SUBMODULE,
        } type;
        void *identifier;
 
-- 
2.8.0.rc3.226.g39d4020