revision.[ch]: document and move code declared around "init"

A subsequent commit will add "REV_INFO_INIT" macro adjacent to
repo_init_revisions(), unfortunately between the "struct rev_info"
itself and that function we've added various miscellaneous code
between the two over the years.

Let's move that code either lower in revision.h, giving it API docs
while we're at it, or in cases where it wasn't public API at all move
it into revision.c No lines of code are changed here, only moved
around. The only changes are the addition of new API comments.

The "tree_difference" variable could also be declared like this, which
I think would be a lot clearer, but let's leave that for now to keep
this a move-only change:

	static enum {
		REV_TREE_SAME,
		REV_TREE_NEW, /* Only new files */
		REV_TREE_OLD, /* Only files removed */
		REV_TREE_DIFFERENT, /* Mixed changes */
	} tree_difference = REV_TREE_SAME;

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

revision.c

@@ -606,6 +606,10 @@ static struct commit *one_relevant_parent(const struct rev_info *revs,
  *
  *   2. We saw anything except REV_TREE_NEW.
  */
+#define REV_TREE_SAME		0
+#define REV_TREE_NEW		1	/* Only new files */
+#define REV_TREE_OLD		2	/* Only files removed */
+#define REV_TREE_DIFFERENT	3	/* Mixed changes */
 static int tree_difference = REV_TREE_SAME;
 
 static void file_add_remove(struct diff_options *options,

revision.h

@@ -329,32 +329,6 @@ struct rev_info {
 	struct tmp_objdir *remerge_objdir;
 };
 
-int ref_excluded(struct string_list *, const char *path);
-void clear_ref_exclusion(struct string_list **);
-void add_ref_exclusion(struct string_list **, const char *exclude);
-
-
-#define REV_TREE_SAME		0
-#define REV_TREE_NEW		1	/* Only new files */
-#define REV_TREE_OLD		2	/* Only files removed */
-#define REV_TREE_DIFFERENT	3	/* Mixed changes */
-
-/* revision.c */
-typedef void (*show_early_output_fn_t)(struct rev_info *, struct commit_list *);
-extern volatile show_early_output_fn_t show_early_output;
-
-struct setup_revision_opt {
-	const char *def;
-	void (*tweak)(struct rev_info *, struct setup_revision_opt *);
-	unsigned int	assume_dashdash:1,
-			allow_exclude_promisor_objects:1;
-	unsigned revarg_opt;
-};
-
-#ifndef NO_THE_REPOSITORY_COMPATIBILITY_MACROS
-#define init_revisions(revs, prefix) repo_init_revisions(the_repository, revs, prefix)
-#endif
-
 /**
  * Initialize a rev_info structure with default values. The third parameter may
  * be NULL or can be prefix path, and then the `.prefix` variable will be set
@@ -366,6 +340,9 @@ struct setup_revision_opt {
 void repo_init_revisions(struct repository *r,
 			 struct rev_info *revs,
 			 const char *prefix);
+#ifndef NO_THE_REPOSITORY_COMPATIBILITY_MACROS
+#define init_revisions(revs, prefix) repo_init_revisions(the_repository, revs, prefix)
+#endif
 
 /**
  * Parse revision information, filling in the `rev_info` structure, and
@@ -374,6 +351,13 @@ void repo_init_revisions(struct repository *r,
  * head of the argument list. The last parameter is used in case no
  * parameter given by the first two arguments.
  */
+struct setup_revision_opt {
+	const char *def;
+	void (*tweak)(struct rev_info *, struct setup_revision_opt *);
+	unsigned int	assume_dashdash:1,
+			allow_exclude_promisor_objects:1;
+	unsigned revarg_opt;
+};
 int setup_revisions(int argc, const char **argv, struct rev_info *revs,
 		    struct setup_revision_opt *);
 
@@ -423,6 +407,14 @@ void mark_trees_uninteresting_sparse(struct repository *r, struct oidset *trees)
 
 void show_object_with_name(FILE *, struct object *, const char *);
 
+/**
+ * Helpers to check if a "struct string_list" item matches with
+ * wildmatch().
+ */
+int ref_excluded(struct string_list *, const char *path);
+void clear_ref_exclusion(struct string_list **);
+void add_ref_exclusion(struct string_list **, const char *exclude);
+
 /**
  * This function can be used if you want to add commit objects as revision
  * information. You can use the `UNINTERESTING` object flag to indicate if
@@ -478,4 +470,10 @@ int rewrite_parents(struct rev_info *revs,
  */
 struct commit_list *get_saved_parents(struct rev_info *revs, const struct commit *commit);
 
+/**
+ * Global for the (undocumented) "--early-output" flag for "git log".
+ */
+typedef void (*show_early_output_fn_t)(struct rev_info *, struct commit_list *);
+extern volatile show_early_output_fn_t show_early_output;
+
 #endif