[PATCH 2/2 v3] log: allow users to follow a file

René Neumann lists at necoro.eu
Tue Mar 24 07:02:26 CET 2015


Hi all,

when cleaning up my cgit installation (and upgrading to a recent
version), I noted that I had the following patch applied. A quick search
revealed, that it has not found its way into cgit. Was this an
oversight, or was it on purpose?

- René

Am 20.04.2013 um 14:21 schrieb John Keeping:
> Teach the "log" UI to behave in the same way as "git log --follow", when
> given a suitable instruction by the user.  The default behaviour remains
> to show the log without following renames, but the follow behaviour can
> be activated by following a link in the page header.
> 
> Follow is not the default because outputting merges in follow mode is
> tricky ("git log --follow" will not show merges).  We also disable the
> graph in follow mode because the commit graph is not simplified so we
> end up with frequent gaps in the graph and many lines that do not
> connect with any commits we're actually showing.
> 
> We also teach the "diff" and "commit" UIs to respect the follow flag on
> URLs, causing the single-file version of these UIs to detect renames.
> This feature is needed only for commits that rename the path we're
> interested in.
> 
> For commits before the file has been renamed (i.e. that appear later in
> the log list) we change the file path in the links from the log to point
> to the old name; this means that links to commits always limit by the
> path known to that commit.  If we didn't do this we would need to walk
> down the log diff'ing every commit whenever we want to show a commit.
> The drawback is that the "Log" link in the top bar of such a page links
> to the log limited by the old name, so it will only show pre-rename
> commits.  I consider this a reasonable trade-off since the "Back" button
> still works and the log matches the path displayed in the top bar.
> 
> Since following renames requires running diff on every commit we
> consider, I've added a knob to the configuration file to globally
> enable/disable this feature.  Note that we may consider a large number
> of commits the revision walking machinery no longer performs any path
> limitation so we have to examine every commit until we find a page full
> of commits that affect the target path or something related to it.
> 
> Suggested-by: René Neumann <necoro at necoro.eu>
> Signed-off-by: John Keeping <john at keeping.me.uk>
> ---
> I've just realised I didn't commit a final fixup to this before sending
> it out.  The difference is in handle_rename() which doesn't leak memory
> in this version.
> 
>  cgit.c        |   4 ++
>  cgit.h        |   2 +
>  cgitrc.5.txt  |   4 ++
>  ui-diff.c     |  35 +++++++++++++++
>  ui-log.c      | 136 ++++++++++++++++++++++++++++++++++++++++++++++++++++------
>  ui-refs.c     |   2 +-
>  ui-repolist.c |   2 +-
>  ui-shared.c   |  28 ++++++++++--
>  ui-shared.h   |   2 +-
>  ui-tree.c     |   2 +-
>  10 files changed, 197 insertions(+), 20 deletions(-)
> 
> diff --git a/cgit.c b/cgit.c
> index 6f44ef2..81312bb 100644
> --- a/cgit.c
> +++ b/cgit.c
> @@ -171,6 +171,8 @@ static void config_cb(const char *name, const char *value)
>  		ctx.cfg.snapshots = cgit_parse_snapshots_mask(value);
>  	else if (!strcmp(name, "enable-filter-overrides"))
>  		ctx.cfg.enable_filter_overrides = atoi(value);
> +	else if (!strcmp(name, "enable-follow-links"))
> +		ctx.cfg.enable_follow_links = atoi(value);
>  	else if (!strcmp(name, "enable-http-clone"))
>  		ctx.cfg.enable_http_clone = atoi(value);
>  	else if (!strcmp(name, "enable-index-links"))
> @@ -338,6 +340,8 @@ static void querystring_cb(const char *name, const char *value)
>  		ctx.qry.context = atoi(value);
>  	} else if (!strcmp(name, "ignorews")) {
>  		ctx.qry.ignorews = atoi(value);
> +	} else if (!strcmp(name, "follow")) {
> +		ctx.qry.follow = atoi(value);
>  	}
>  }
>  
> diff --git a/cgit.h b/cgit.h
> index b56e756..c0758b0 100644
> --- a/cgit.h
> +++ b/cgit.h
> @@ -163,6 +163,7 @@ struct cgit_query {
>  	int show_all;
>  	int context;
>  	int ignorews;
> +	int follow;
>  	char *vpath;
>  };
>  
> @@ -203,6 +204,7 @@ struct cgit_config {
>  	int case_sensitive_sort;
>  	int embedded;
>  	int enable_filter_overrides;
> +	int enable_follow_links;
>  	int enable_http_clone;
>  	int enable_index_links;
>  	int enable_index_owner;
> diff --git a/cgitrc.5.txt b/cgitrc.5.txt
> index 39b031e..48ef249 100644
> --- a/cgitrc.5.txt
> +++ b/cgitrc.5.txt
> @@ -121,6 +121,10 @@ enable-filter-overrides::
>  	Flag which, when set to "1", allows all filter settings to be
>  	overridden in repository-specific cgitrc files. Default value: none.
>  
> +enable-follow-links::
> +	Flag which, when set to "1", allows users to follow a file in the log
> +	view.  Default value: "0".
> +
>  enable-http-clone::
>  	If set to "1", cgit will act as an dumb HTTP endpoint for git clones.
>  	If you use an alternate way of serving git repositories, you may wish
> diff --git a/ui-diff.c b/ui-diff.c
> index 8b38209..2d75f34 100644
> --- a/ui-diff.c
> +++ b/ui-diff.c
> @@ -36,6 +36,7 @@ static struct fileinfo {
>  
>  static int use_ssdiff = 0;
>  static struct diff_filepair *current_filepair;
> +static const char *current_prefix;
>  
>  struct diff_filespec *cgit_get_current_old_file(void)
>  {
> @@ -132,11 +133,30 @@ static void count_diff_lines(char *line, int len)
>  	}
>  }
>  
> +static int show_filepair(struct diff_filepair *pair)
> +{
> +	/* Always show if we have no limiting prefix. */
> +	if (!current_prefix)
> +		return 1;
> +
> +	/* Show if either path in the pair begins with the prefix. */
> +	if (!prefixcmp(pair->one->path, current_prefix) ||
> +	    !prefixcmp(pair->two->path, current_prefix))
> +		return 1;
> +
> +	/* Otherwise we don't want to show this filepair. */
> +	return 0;
> +}
> +
>  static void inspect_filepair(struct diff_filepair *pair)
>  {
>  	int binary = 0;
>  	unsigned long old_size = 0;
>  	unsigned long new_size = 0;
> +
> +	if (!show_filepair(pair))
> +		return;
> +
>  	files++;
>  	lines_added = 0;
>  	lines_removed = 0;
> @@ -279,6 +299,9 @@ static void filepair_cb(struct diff_filepair *pair)
>  	int binary = 0;
>  	linediff_fn print_line_fn = print_line;
>  
> +	if (!show_filepair(pair))
> +		return;
> +
>  	current_filepair = pair;
>  	if (use_ssdiff) {
>  		cgit_ssdiff_header_begin();
> @@ -364,6 +387,18 @@ void cgit_print_diff(const char *new_rev, const char *old_rev,
>  	unsigned long size;
>  	struct commit *commit, *commit2;
>  
> +	/*
> +	 * If "follow" is set then the diff machinery needs to examine the
> +	 * entire commit to detect renames so we must limit the paths in our
> +	 * own callbacks and not pass the prefix to the diff machinery.
> +	 */
> +	if (ctx.qry.follow && ctx.cfg.enable_follow_links) {
> +		current_prefix = prefix;
> +		prefix = "";
> +	} else {
> +		current_prefix = NULL;
> +	}
> +
>  	if (!new_rev)
>  		new_rev = ctx.qry.head;
>  	get_sha1(new_rev, new_rev_sha1);
> diff --git a/ui-log.c b/ui-log.c
> index 2aa12c3..6bab166 100644
> --- a/ui-log.c
> +++ b/ui-log.c
> @@ -12,7 +12,7 @@
>  #include "ui-shared.h"
>  #include "vector.h"
>  
> -int files, add_lines, rem_lines;
> +int files, add_lines, rem_lines, lines_counted;
>  
>  /*
>   * The list of available column colors in the commit graph.
> @@ -66,7 +66,7 @@ void show_commit_decorations(struct commit *commit)
>  			strncpy(buf, deco->name + 11, sizeof(buf) - 1);
>  			cgit_log_link(buf, NULL, "branch-deco", buf, NULL,
>  				      ctx.qry.vpath, 0, NULL, NULL,
> -				      ctx.qry.showmsg);
> +				      ctx.qry.showmsg, 0);
>  		}
>  		else if (!prefixcmp(deco->name, "tag: refs/tags/")) {
>  			strncpy(buf, deco->name + 15, sizeof(buf) - 1);
> @@ -83,7 +83,7 @@ void show_commit_decorations(struct commit *commit)
>  			cgit_log_link(buf, NULL, "remote-deco", NULL,
>  				      sha1_to_hex(commit->object.sha1),
>  				      ctx.qry.vpath, 0, NULL, NULL,
> -				      ctx.qry.showmsg);
> +				      ctx.qry.showmsg, 0);
>  		}
>  		else {
>  			strncpy(buf, deco->name, sizeof(buf) - 1);
> @@ -96,6 +96,74 @@ next:
>  	}
>  }
>  
> +static void handle_rename(struct diff_filepair *pair)
> +{
> +	/*
> +	 * After we have seen a rename, we generate links to the previous
> +	 * name of the file so that commit & diff views get fed the path
> +	 * that is correct for the commit they are showing, avoiding the
> +	 * need to walk the entire history leading back to every commit we
> +	 * show in order detect renames.
> +	 */
> +	if (0 != strcmp(ctx.qry.vpath, pair->two->path)) {
> +		free(ctx.qry.vpath);
> +		ctx.qry.vpath = xstrdup(pair->two->path);
> +	}
> +	inspect_files(pair);
> +}
> +
> +static int show_commit(struct commit *commit, struct rev_info *revs)
> +{
> +	struct commit_list *parents = commit->parents;
> +	struct commit *parent;
> +	int found = 0, saved_fmt;
> +	unsigned saved_flags = revs->diffopt.flags;
> +
> +
> +	/* Always show if we're not in "follow" mode with a single file. */
> +	if (!ctx.qry.follow)
> +		return 1;
> +
> +	/*
> +	 * In "follow" mode, we don't show merges.  This is consistent with
> +	 * "git log --follow -- <file>".
> +	 */
> +	if (parents && parents->next)
> +		return 0;
> +
> +	/*
> +	 * If this is the root commit, do what rev_info tells us.
> +	 */
> +	if (!parents)
> +		return revs->show_root_diff;
> +
> +	/* When we get here we have precisely one parent. */
> +	parent = parents->item;
> +	parse_commit(parent);
> +
> +	files = 0;
> +	add_lines = 0;
> +	rem_lines = 0;
> +
> +	DIFF_OPT_SET(&revs->diffopt, RECURSIVE);
> +	diff_tree_sha1(parent->tree->object.sha1,
> +		       commit->tree->object.sha1,
> +		       "", &revs->diffopt);
> +	diffcore_std(&revs->diffopt);
> +
> +	found = !diff_queue_is_empty();
> +	saved_fmt = revs->diffopt.output_format;
> +	revs->diffopt.output_format = DIFF_FORMAT_CALLBACK;
> +	revs->diffopt.format_callback = cgit_diff_tree_cb;
> +	revs->diffopt.format_callback_data = handle_rename;
> +	diff_flush(&revs->diffopt);
> +	revs->diffopt.output_format = saved_fmt;
> +	revs->diffopt.flags = saved_flags;
> +
> +	lines_counted = 1;
> +	return found;
> +}
> +
>  static void print_commit(struct commit *commit, struct rev_info *revs)
>  {
>  	struct commitinfo *info;
> @@ -173,7 +241,8 @@ static void print_commit(struct commit *commit, struct rev_info *revs)
>  		cgit_print_age(commit->date, TM_WEEK * 2, FMT_SHORTDATE);
>  	}
>  
> -	if (ctx.repo->enable_log_filecount || ctx.repo->enable_log_linecount) {
> +	if (!lines_counted && (ctx.repo->enable_log_filecount ||
> +			       ctx.repo->enable_log_linecount)) {
>  		files = 0;
>  		add_lines = 0;
>  		rem_lines = 0;
> @@ -324,7 +393,17 @@ void cgit_print_log(const char *tip, int ofs, int cnt, char *grep, char *pattern
>  			}
>  		}
>  	}
> -	if (commit_graph) {
> +
> +	if (!path || !ctx.cfg.enable_follow_links) {
> +		/*
> +		 * If we don't have a path, "follow" is a no-op so make sure
> +		 * the variable is set to false to avoid needing to check
> +		 * both this and whether we have a path everywhere.
> +		 */
> +		ctx.qry.follow = 0;
> +	}
> +
> +	if (commit_graph && !ctx.qry.follow) {
>  		static const char *graph_arg = "--graph";
>  		static const char *color_arg = "--color";
>  		vector_push(&vec, &graph_arg, 0);
> @@ -342,7 +421,10 @@ void cgit_print_log(const char *tip, int ofs, int cnt, char *grep, char *pattern
>  	}
>  
>  	if (path) {
> +		static const char *follow_arg = "--follow";
>  		static const char *double_dash_arg = "--";
> +		if (ctx.qry.follow)
> +			vector_push(&vec, &follow_arg, 0);
>  		vector_push(&vec, &double_dash_arg, 0);
>  		vector_push(&vec, &path, 0);
>  	}
> @@ -356,10 +438,17 @@ void cgit_print_log(const char *tip, int ofs, int cnt, char *grep, char *pattern
>  	rev.commit_format = CMIT_FMT_DEFAULT;
>  	rev.verbose_header = 1;
>  	rev.show_root_diff = 0;
> +	rev.simplify_history = 1;
>  	setup_revisions(vec.count, vec.data, &rev, NULL);
>  	load_ref_decorations(DECORATE_FULL_REFS);
>  	rev.show_decorations = 1;
>  	rev.grep_filter.regflags |= REG_ICASE;
> +
> +	rev.diffopt.detect_rename = 1;
> +	rev.diffopt.rename_limit = ctx.cfg.renamelimit;
> +	if (ctx.qry.ignorews)
> +		DIFF_XDL_SET(&rev.diffopt, IGNORE_WHITESPACE);
> +
>  	compile_grep_patterns(&rev.grep_filter);
>  	prepare_revision_walk(&rev);
>  
> @@ -377,11 +466,12 @@ void cgit_print_log(const char *tip, int ofs, int cnt, char *grep, char *pattern
>  		cgit_log_link(ctx.qry.showmsg ? "Collapse" : "Expand", NULL,
>  			      NULL, ctx.qry.head, ctx.qry.sha1,
>  			      ctx.qry.vpath, ctx.qry.ofs, ctx.qry.grep,
> -			      ctx.qry.search, ctx.qry.showmsg ? 0 : 1);
> +			      ctx.qry.search, ctx.qry.showmsg ? 0 : 1,
> +			      ctx.qry.follow);
>  		html(")");
>  	}
>  	html("</th><th class='left'>Author</th>");
> -	if (commit_graph)
> +	if (rev.graph)
>  		html("<th class='left'>Age</th>");
>  	if (ctx.repo->enable_log_filecount) {
>  		html("<th class='left'>Files</th>");
> @@ -396,15 +486,32 @@ void cgit_print_log(const char *tip, int ofs, int cnt, char *grep, char *pattern
>  	if (ofs<0)
>  		ofs = 0;
>  
> -	for (i = 0; i < ofs && (commit = get_revision(&rev)) != NULL; i++) {
> +	for (i = 0; i < ofs && (commit = get_revision(&rev)) != NULL;) {
> +		if (show_commit(commit, &rev))
> +			i++;
>  		free(commit->buffer);
>  		commit->buffer = NULL;
>  		free_commit_list(commit->parents);
>  		commit->parents = NULL;
>  	}
>  
> -	for (i = 0; i < cnt && (commit = get_revision(&rev)) != NULL; i++) {
> -		print_commit(commit, &rev);
> +	for (i = 0; i < cnt && (commit = get_revision(&rev)) != NULL;) {
> +		/*
> +		 * In "follow" mode, we must count the files and lines the
> +		 * first time we invoke diff on a given commit, and we need
> +		 * to do that to see if the commit touches the path we care
> +		 * about, so we do it in show_commit.  Hence we must clear
> +		 * lines_counted here.
> +		 *
> +		 * This has the side effect of avoiding running diff twice
> +		 * when we are both following renames and showing file
> +		 * and/or line counts.
> +		 */
> +		lines_counted = 0;
> +		if (show_commit(commit, &rev)) {
> +			i++;
> +			print_commit(commit, &rev);
> +		}
>  		free(commit->buffer);
>  		commit->buffer = NULL;
>  		free_commit_list(commit->parents);
> @@ -417,7 +524,8 @@ void cgit_print_log(const char *tip, int ofs, int cnt, char *grep, char *pattern
>  			cgit_log_link("[prev]", NULL, NULL, ctx.qry.head,
>  				      ctx.qry.sha1, ctx.qry.vpath,
>  				      ofs - cnt, ctx.qry.grep,
> -				      ctx.qry.search, ctx.qry.showmsg);
> +				      ctx.qry.search, ctx.qry.showmsg,
> +				      ctx.qry.follow);
>  			html("</li>");
>  		}
>  		if ((commit = get_revision(&rev)) != NULL) {
> @@ -425,14 +533,16 @@ void cgit_print_log(const char *tip, int ofs, int cnt, char *grep, char *pattern
>  			cgit_log_link("[next]", NULL, NULL, ctx.qry.head,
>  				      ctx.qry.sha1, ctx.qry.vpath,
>  				      ofs + cnt, ctx.qry.grep,
> -				      ctx.qry.search, ctx.qry.showmsg);
> +				      ctx.qry.search, ctx.qry.showmsg,
> +				      ctx.qry.follow);
>  			html("</li>");
>  		}
>  		html("</ul>");
>  	} else if ((commit = get_revision(&rev)) != NULL) {
>  		htmlf("<tr class='nohover'><td colspan='%d'>", columns);
>  		cgit_log_link("[...]", NULL, NULL, ctx.qry.head, NULL,
> -			      ctx.qry.vpath, 0, NULL, NULL, ctx.qry.showmsg);
> +			      ctx.qry.vpath, 0, NULL, NULL, ctx.qry.showmsg,
> +			      ctx.qry.follow);
>  		html("</td></tr>\n");
>  	}
>  
> diff --git a/ui-refs.c b/ui-refs.c
> index 0ae0612..f4eefd1 100644
> --- a/ui-refs.c
> +++ b/ui-refs.c
> @@ -71,7 +71,7 @@ static int print_branch(struct refinfo *ref)
>  		return 1;
>  	html("<tr><td>");
>  	cgit_log_link(name, NULL, NULL, name, NULL, NULL, 0, NULL, NULL,
> -		      ctx.qry.showmsg);
> +		      ctx.qry.showmsg, 0);
>  	html("</td><td>");
>  
>  	if (ref->object->type == OBJ_COMMIT) {
> diff --git a/ui-repolist.c b/ui-repolist.c
> index 47ca997..d96f252 100644
> --- a/ui-repolist.c
> +++ b/ui-repolist.c
> @@ -314,7 +314,7 @@ void cgit_print_repolist()
>  			html("<td>");
>  			cgit_summary_link("summary", NULL, "button", NULL);
>  			cgit_log_link("log", NULL, "button", NULL, NULL, NULL,
> -				      0, NULL, NULL, ctx.qry.showmsg);
> +				      0, NULL, NULL, ctx.qry.showmsg, 0);
>  			cgit_tree_link("tree", NULL, "button", NULL, NULL, NULL);
>  			html("</td>");
>  		}
> diff --git a/ui-shared.c b/ui-shared.c
> index 519eef7..04d0368 100644
> --- a/ui-shared.c
> +++ b/ui-shared.c
> @@ -284,7 +284,8 @@ void cgit_plain_link(const char *name, const char *title, const char *class,
>  
>  void cgit_log_link(const char *name, const char *title, const char *class,
>  		   const char *head, const char *rev, const char *path,
> -		   int ofs, const char *grep, const char *pattern, int showmsg)
> +		   int ofs, const char *grep, const char *pattern, int showmsg,
> +		   int follow)
>  {
>  	char *delim;
>  
> @@ -313,6 +314,11 @@ void cgit_log_link(const char *name, const char *title, const char *class,
>  	if (showmsg) {
>  		html(delim);
>  		html("showmsg=1");
> +		delim = "&";
> +	}
> +	if (follow) {
> +		html(delim);
> +		html("follow=1");
>  	}
>  	html("'>");
>  	html_txt(name);
> @@ -355,6 +361,10 @@ void cgit_commit_link(char *name, const char *title, const char *class,
>  		html("ignorews=1");
>  		delim = "&";
>  	}
> +	if (ctx.qry.follow) {
> +		html(delim);
> +		html("follow=1");
> +	}
>  	html("'>");
>  	if (name[0] != '\0')
>  		html_txt(name);
> @@ -411,6 +421,10 @@ void cgit_diff_link(const char *name, const char *title, const char *class,
>  		html("ignorews=1");
>  		delim = "&";
>  	}
> +	if (ctx.qry.follow) {
> +		html(delim);
> +		html("follow=1");
> +	}
>  	html("'>");
>  	html_txt(name);
>  	html("</a>");
> @@ -452,7 +466,7 @@ static void cgit_self_link(char *name, const char *title, const char *class,
>  			      ctx->qry.has_sha1 ? ctx->qry.sha1 : NULL,
>  			      ctx->qry.path, ctx->qry.ofs,
>  			      ctx->qry.grep, ctx->qry.search,
> -			      ctx->qry.showmsg);
> +			      ctx->qry.showmsg, ctx->qry.follow);
>  	else if (!strcmp(ctx->qry.page, "commit"))
>  		cgit_commit_link(name, title, class, ctx->qry.head,
>  				 ctx->qry.has_sha1 ? ctx->qry.sha1 : NULL,
> @@ -854,7 +868,7 @@ void cgit_print_pageheader(struct cgit_context *ctx)
>  			       ctx->qry.sha1, NULL);
>  		cgit_log_link("log", NULL, hc(ctx, "log"), ctx->qry.head,
>  			      NULL, ctx->qry.vpath, 0, NULL, NULL,
> -			      ctx->qry.showmsg);
> +			      ctx->qry.showmsg, ctx->qry.follow);
>  		cgit_tree_link("tree", NULL, hc(ctx, "tree"), ctx->qry.head,
>  			       ctx->qry.sha1, ctx->qry.vpath);
>  		cgit_commit_link("commit", NULL, hc(ctx, "commit"),
> @@ -906,6 +920,14 @@ void cgit_print_pageheader(struct cgit_context *ctx)
>  		html("<div class='path'>");
>  		html("path: ");
>  		cgit_print_path_crumbs(ctx, ctx->qry.vpath);
> +		if (ctx->cfg.enable_follow_links && !strcmp(ctx->qry.page, "log")) {
> +			html(" (");
> +			ctx->qry.follow = !ctx->qry.follow;
> +			cgit_self_link(ctx->qry.follow ? "follow" : "unfollow",
> +					NULL, NULL, ctx);
> +			ctx->qry.follow = !ctx->qry.follow;
> +			html(")");
> +		}
>  		html("</div>");
>  	}
>  	html("<div class='content'>");
> diff --git a/ui-shared.h b/ui-shared.h
> index 5987e77..3156846 100644
> --- a/ui-shared.h
> +++ b/ui-shared.h
> @@ -26,7 +26,7 @@ extern void cgit_plain_link(const char *name, const char *title,
>  extern void cgit_log_link(const char *name, const char *title,
>  			  const char *class, const char *head, const char *rev,
>  			  const char *path, int ofs, const char *grep,
> -			  const char *pattern, int showmsg);
> +			  const char *pattern, int showmsg, int follow);
>  extern void cgit_commit_link(char *name, const char *title,
>  			     const char *class, const char *head,
>  			     const char *rev, const char *path,
> diff --git a/ui-tree.c b/ui-tree.c
> index aa5dee9..ebb3e9b 100644
> --- a/ui-tree.c
> +++ b/ui-tree.c
> @@ -169,7 +169,7 @@ static int ls_item(const unsigned char *sha1, const char *base, int baselen,
>  	html("<td>");
>  	cgit_log_link("log", NULL, "button", ctx.qry.head,
>  		      walk_tree_ctx->curr_rev, fullpath.buf, 0, NULL, NULL,
> -		      ctx.qry.showmsg);
> +		      ctx.qry.showmsg, 0);
>  	if (ctx.repo->max_stats)
>  		cgit_stats_link("stats", NULL, "button", ctx.qry.head,
>  				fullpath.buf);
> 


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