[RFC,05/13] walken: configure rev_info and prepare for walk
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Message ID 20190607010811.52944-6-emilyshaffer@google.com
State New
Headers show
Series
  • example implementation of revwalk tutorial
Related show

Commit Message

Emily Shaffer June 7, 2019, 1:08 a.m. UTC
`struct rev_info` is what's used by the struct itself.
`repo_init_revisions()` initializes the struct; then we need to set it
up for the walk we want to perform, which is done in
`final_rev_info_setup()`.

The most important step here is adding the first object we want to walk
to the pending array. Here, we take the easy road and use
`add_head_to_pending()`; there is also a way to do it with
`setup_revision_opt()` and `setup_revisions()` which we demonstrate but
do not use. If we were to forget this step, the walk would do nothing -
the pending queue would be checked, determined to be empty, and the walk
would terminate immediately.

Signed-off-by: Emily Shaffer <emilyshaffer@google.com>
---
 builtin/walken.c | 42 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 42 insertions(+)

Patch
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diff --git a/builtin/walken.c b/builtin/walken.c
index 5d1666a5da..c101db38c7 100644
--- a/builtin/walken.c
+++ b/builtin/walken.c
@@ -6,6 +6,7 @@ 
 
 #include <stdio.h>
 #include "builtin.h"
+#include "revision.h"
 #include "config.h"
 #include "parse-options.h"
 
@@ -26,6 +27,35 @@  static void init_walken_defaults(void)
 	 */
 }
 
+/*
+ * cmd_log calls a second set of init after the repo_init_revisions call. We'll
+ * mirror those settings in post_repo_init_init.
+ */
+static void final_rev_info_setup(int argc, const char **argv, const char *prefix,
+		struct rev_info *rev)
+{
+	struct setup_revision_opt opt;
+
+	/* setup_revision_opt is used to pass options to the setup_revisions()
+	 * call. It's got some special items for submodules and other types of
+	 * optimizations, but for now, we'll just point it to HEAD and call it
+	 * good. First we should make sure to reset it. TODO: This is useful for
+	 * more complicated stuff revisions, but a decent shortcut for the first
+	 * pass is add_head_to_pending().
+	 */
+	memset(&opt, 0, sizeof(opt));
+	opt.def = "HEAD";
+	opt.revarg_opt = REVARG_COMMITTISH;
+	//setup_revisions(argc, argv, rev, &opt);
+
+	/* Let's force oneline format. */
+	get_commit_format("oneline", rev);
+	rev->verbose_header = 1;
+	
+	/* add the HEAD to pending so we can start */
+	add_head_to_pending(rev);
+}
+
 /*
  * This method will be called back by git_config(). It is used to gather values
  * from the configuration files available to Git.
@@ -54,12 +84,24 @@  int cmd_walken(int argc, const char **argv, const char *prefix)
 		OPT_END()
 	};
 
+	struct rev_info rev;
+
 	argc = parse_options(argc, argv, prefix, options, walken_usage, 0);
 
 	init_walken_defaults();
 
 	git_config(git_walken_config, NULL);
 
+	/* Time to set up the walk. repo_init_revisions sets up rev_info with
+	 * the defaults, but then you need to make some configuration settings
+	 * to make it do what's special about your walk.
+	 */
+	repo_init_revisions(the_repository, &rev, prefix);
+
+	/* Before we do the walk, we need to set a starting point. It's not
+	 * coming from opt. */
+	final_rev_info_setup(argc, argv, prefix, &rev);
+
 	printf(_("cmd_walken incoming...\n"));
 	return 0;
 }