ui-stats: replace 'enable-stats' setting with 'max-stats'

The new 'max-stats' and 'repo.max-stats' settings makes it possible to
define the maximum statistics period, both globally and per repo. Hence,
it is now feasible to allow statistics on repositories with a high commit
frequency, like linux-2.6, by setting repo.max-stats to e.g. 'month'.

Signed-off-by: Lars Hjemli <hjemli@gmail.com>

8 files changed, 104 insertions, 58 deletions

diff --git a/cgit.c b/cgit.c
index 22b6d7c..57e11cd 100644
--- a/cgit.c
+++ b/cgit.c
@@ -3,24 +3,25 @@
  * Copyright (C) 2006 Lars Hjemli
  *
  * Licensed under GNU General Public License v2
  *   (see COPYING for full license text)
  */
 
 #include "cgit.h"
 #include "cache.h"
 #include "cmd.h"
 #include "configfile.h"
 #include "html.h"
 #include "ui-shared.h"
+#include "ui-stats.h"
 #include "scan-tree.h"
 
 const char *cgit_version = CGIT_VERSION;
 
 void config_cb(const char *name, const char *value)
 {
         if (!strcmp(name, "root-title"))
                 ctx.cfg.root_title = xstrdup(value);
         else if (!strcmp(name, "root-desc"))
                 ctx.cfg.root_desc = xstrdup(value);
         else if (!strcmp(name, "root-readme"))
                 ctx.cfg.root_readme = xstrdup(value);
@@ -45,26 +46,26 @@ void config_cb(const char *name, const char *value)
                 if (!ctx.cfg.virtual_root && (!strcmp(value, "/")))
                         ctx.cfg.virtual_root = "";
         } else if (!strcmp(name, "nocache"))
                 ctx.cfg.nocache = atoi(value);
         else if (!strcmp(name, "snapshots"))
                 ctx.cfg.snapshots = cgit_parse_snapshots_mask(value);
         else if (!strcmp(name, "enable-index-links"))
                 ctx.cfg.enable_index_links = atoi(value);
         else if (!strcmp(name, "enable-log-filecount"))
                 ctx.cfg.enable_log_filecount = atoi(value);
         else if (!strcmp(name, "enable-log-linecount"))
                 ctx.cfg.enable_log_linecount = atoi(value);
-        else if (!strcmp(name, "enable-stats"))
-                ctx.cfg.enable_stats = atoi(value);
+        else if (!strcmp(name, "max-stats"))
+                ctx.cfg.max_stats = cgit_find_stats_period(value, NULL);
         else if (!strcmp(name, "cache-size"))
                 ctx.cfg.cache_size = atoi(value);
         else if (!strcmp(name, "cache-root"))
                 ctx.cfg.cache_root = xstrdup(value);
         else if (!strcmp(name, "cache-root-ttl"))
                 ctx.cfg.cache_root_ttl = atoi(value);
         else if (!strcmp(name, "cache-repo-ttl"))
                 ctx.cfg.cache_repo_ttl = atoi(value);
         else if (!strcmp(name, "cache-static-ttl"))
                 ctx.cfg.cache_static_ttl = atoi(value);
         else if (!strcmp(name, "cache-dynamic-ttl"))
                 ctx.cfg.cache_dynamic_ttl = atoi(value);
@@ -105,26 +106,26 @@ void config_cb(const char *name, const char *value)
         else if (ctx.repo && !strcmp(name, "repo.desc"))
                 ctx.repo->desc = xstrdup(value);
         else if (ctx.repo && !strcmp(name, "repo.owner"))
                 ctx.repo->owner = xstrdup(value);
         else if (ctx.repo && !strcmp(name, "repo.defbranch"))
                 ctx.repo->defbranch = xstrdup(value);
         else if (ctx.repo && !strcmp(name, "repo.snapshots"))
                 ctx.repo->snapshots = ctx.cfg.snapshots & cgit_parse_snapshots_mask(value); /* XXX: &? */
         else if (ctx.repo && !strcmp(name, "repo.enable-log-filecount"))
                 ctx.repo->enable_log_filecount = ctx.cfg.enable_log_filecount * atoi(value);
         else if (ctx.repo && !strcmp(name, "repo.enable-log-linecount"))
                 ctx.repo->enable_log_linecount = ctx.cfg.enable_log_linecount * atoi(value);
-        else if (ctx.repo && !strcmp(name, "repo.enable-stats"))
-                ctx.repo->enable_stats = ctx.cfg.enable_stats && atoi(value);
+        else if (ctx.repo && !strcmp(name, "repo.max-stats"))
+                ctx.repo->max_stats = cgit_find_stats_period(value, NULL);
         else if (ctx.repo && !strcmp(name, "repo.module-link"))
                 ctx.repo->module_link= xstrdup(value);
         else if (ctx.repo && !strcmp(name, "repo.readme") && value != NULL) {
                 if (*value == '/')
                         ctx.repo->readme = xstrdup(value);
                 else
                         ctx.repo->readme = xstrdup(fmt("%s/%s", ctx.repo->path, value));
         } else if (!strcmp(name, "include"))
                 parse_configfile(value, config_cb);
 }
 
 static void querystring_cb(const char *name, const char *value)
@@ -174,24 +175,25 @@ static void prepare_context(struct cgit_context *ctx)
         ctx->cfg.cache_repo_ttl = 5;
         ctx->cfg.cache_root = CGIT_CACHE_ROOT;
         ctx->cfg.cache_root_ttl = 5;
         ctx->cfg.cache_static_ttl = -1;
         ctx->cfg.css = "/cgit.css";
         ctx->cfg.logo = "/git-logo.png";
         ctx->cfg.local_time = 0;
         ctx->cfg.max_repo_count = 50;
         ctx->cfg.max_commit_count = 50;
         ctx->cfg.max_lock_attempts = 5;
         ctx->cfg.max_msg_len = 80;
         ctx->cfg.max_repodesc_len = 80;
+        ctx->cfg.max_stats = 0;
         ctx->cfg.module_link = "./?repo=%s&page=commit&id=%s";
         ctx->cfg.renamelimit = -1;
         ctx->cfg.robots = "index, nofollow";
         ctx->cfg.root_title = "Git repository browser";
         ctx->cfg.root_desc = "a fast webinterface for the git dscm";
         ctx->cfg.script_name = CGIT_SCRIPT_NAME;
         ctx->cfg.summary_branches = 10;
         ctx->cfg.summary_log = 10;
         ctx->cfg.summary_tags = 10;
         ctx->page.mimetype = "text/html";
         ctx->page.charset = PAGE_ENCODING;
         ctx->page.filename = NULL;
diff --git a/cgit.h b/cgit.h
index 85045c4..f2cb671 100644
--- a/cgit.h
+++ b/cgit.h
@@ -52,25 +52,25 @@ struct cgit_repo {
         char *name;
         char *path;
         char *desc;
         char *owner;
         char *defbranch;
         char *group;
         char *module_link;
         char *readme;
         char *clone_url;
         int snapshots;
         int enable_log_filecount;
         int enable_log_linecount;
-        int enable_stats;
+        int max_stats;
 };
 
 struct cgit_repolist {
         int length;
         int count;
         struct cgit_repo *repos;
 };
 
 struct commitinfo {
         struct commit *commit;
         char *author;
         char *author_email;
@@ -144,31 +144,31 @@ struct cgit_config {
         char *root_readme;
         char *script_name;
         char *virtual_root;
         int cache_size;
         int cache_dynamic_ttl;
         int cache_max_create_time;
         int cache_repo_ttl;
         int cache_root_ttl;
         int cache_static_ttl;
         int enable_index_links;
         int enable_log_filecount;
         int enable_log_linecount;
-        int enable_stats;
         int local_time;
         int max_repo_count;
         int max_commit_count;
         int max_lock_attempts;
         int max_msg_len;
         int max_repodesc_len;
+        int max_stats;
         int nocache;
         int renamelimit;
         int snapshots;
         int summary_branches;
         int summary_log;
         int summary_tags;
 };
 
 struct cgit_page {
         time_t modified;
         time_t expires;
         size_t size;
diff --git a/cgitrc.5.txt b/cgitrc.5.txt
index 60d3ea4..0bbbea3 100644
--- a/cgitrc.5.txt
+++ b/cgitrc.5.txt
@@ -65,28 +65,24 @@ enable-index-links
         "commit" and "tree" pages). Default value: "0".
 
 enable-log-filecount
         Flag which, when set to "1", will make cgit print the number of
         modified files for each commit on the repository log page. Default
         value: "0".
 
 enable-log-linecount
         Flag which, when set to "1", will make cgit print the number of added
         and removed lines for each commit on the repository log page. Default
         value: "0".
 
-enable-stats
-        Globally enable/disable statistics for each repository. Default
-        value: "0".
-
 favicon
         Url used as link to a shortcut icon for cgit. If specified, it is
         suggested to use the value "/favicon.ico" since certain browsers will
         ignore other values. Default value: none.
 
 footer
         The content of the file specified with this option will be included
         verbatim at the bottom of all pages (i.e. it replaces the standard
         "generated by..." message. Default value: none.
 
 include
         Name of a configfile to include before the rest of the current config-
@@ -124,24 +120,29 @@ max-commit-count
 max-message-length
         Specifies the maximum number of commit message characters to display in
         "log" view. Default value: "80".
 
 max-repo-count
                 Specifies the number of entries to list per page on therepository
         index page. Default value: "50".
 
 max-repodesc-length
         Specifies the maximum number of repo description characters to display
         on the repository index page. Default value: "80".
 
+max-stats
+        Set the default maximum statistics period. Valid values are "week",
+        "month", "quarter" and "year". If unspecified, statistics are
+        disabled. Default value: none. See also: "repo.max-stats".
+
 module-link
         Text which will be used as the formatstring for a hyperlink when a
         submodule is printed in a directory listing. The arguments for the
         formatstring are the path and SHA1 of the submodule commit. Default
         value: "./?repo=%s&page=commit&id=%s"
 
 nocache
         If set to the value "1" caching will be disabled. This settings is
         deprecated, and will not be honored starting with cgit-1.0. Default
         value: "0".
 
 renamelimit
@@ -213,27 +214,28 @@ repo.defbranch
 
 repo.desc
         The value to show as repository description. Default value: none.
 
 repo.enable-log-filecount
         A flag which can be used to disable the global setting
         `enable-log-filecount'. Default value: none.
 
 repo.enable-log-linecount
         A flag which can be used to disable the global setting
         `enable-log-linecount'. Default value: none.
 
-repo.enable-stats
-        A flag which can be used to disable the global setting
-        `enable-stats'. Default value: none.
+repo.max-stats
+        Override the default maximum statistics period. Valid values are equal
+        to the values specified for the global "max-stats" setting. Default
+        value: none.
 
 repo.name
         The value to show as repository name. Default value: <repo.url>.
 
 repo.owner
         A value used to identify the owner of the repository. Default value:
         none.
 
 repo.path
         An absolute path to the repository directory. For non-bare repositories
         this is the .git-directory. Default value: none.
 
@@ -275,24 +277,28 @@ enable-log-filecount=1
 # Show number of added/removed lines per commit on the log pages
 enable-log-linecount=1
 
 
 # Add a cgit favicon
 favicon=/favicon.ico
 
 
 # Use a custom logo
 logo=/img/mylogo.png
 
 
+# Enable statistics per week, month and quarter
+max-stats=quarter
+
+
 # Set the title and heading of the repository index page
 root-title=foobar.com git repositories
 
 
 # Set a subheading for the repository index page
 root-desc=tracking the foobar development
 
 
 # Include some more info about foobar.com on the index page
 root-readme=/var/www/htdocs/about.html
 
 
@@ -347,24 +353,27 @@ repo.desc=the dscm
 
 
 repo.url=linux
 repo.path=/pub/git/linux.git
 repo.desc=the kernel
 
 # Disable adhoc downloads of this repo
 repo.snapshots=0
 
 # Disable line-counts for this repo
 repo.enable-log-linecount=0
 
+# Restrict the max statistics period for this repo
+repo.max-stats=month
+
 
 BUGS
 ----
 Comments currently cannot appear on the same line as a setting; the comment
 will be included as part of the value. E.g. this line:
 
         robots=index  # allow indexing
 
 will generate the following html element:
 
         <meta name='robots' content='index  # allow indexing'/>
 
diff --git a/cmd.c b/cmd.c
index 744bf84..763a558 100644
--- a/cmd.c
+++ b/cmd.c
@@ -103,28 +103,25 @@ static void refs_fn(struct cgit_context *ctx)
         cgit_print_refs();
 }
 
 static void snapshot_fn(struct cgit_context *ctx)
 {
         cgit_print_snapshot(ctx->qry.head, ctx->qry.sha1,
                             cgit_repobasename(ctx->repo->url), ctx->qry.path,
                             ctx->repo->snapshots, ctx->qry.nohead);
 }
 
 static void stats_fn(struct cgit_context *ctx)
 {
-        if (ctx->repo->enable_stats)
-                cgit_show_stats(ctx);
-        else
-                cgit_print_error("Stats disabled for this repo");
+        cgit_show_stats(ctx);
 }
 
 static void summary_fn(struct cgit_context *ctx)
 {
         cgit_print_summary();
 }
 
 static void tag_fn(struct cgit_context *ctx)
 {
         cgit_print_tag(ctx->qry.sha1);
 }
 
diff --git a/shared.c b/shared.c
index 37333f0..7382609 100644
--- a/shared.c
+++ b/shared.c
@@ -49,25 +49,25 @@ struct cgit_repo *cgit_add_repo(const char *url)
 
         ret = &cgit_repolist.repos[cgit_repolist.count-1];
         ret->url = trim_end(url, '/');
         ret->name = ret->url;
         ret->path = NULL;
         ret->desc = "[no description]";
         ret->owner = NULL;
         ret->group = ctx.cfg.repo_group;
         ret->defbranch = "master";
         ret->snapshots = ctx.cfg.snapshots;
         ret->enable_log_filecount = ctx.cfg.enable_log_filecount;
         ret->enable_log_linecount = ctx.cfg.enable_log_linecount;
-        ret->enable_stats = ctx.cfg.enable_stats;
+        ret->max_stats = ctx.cfg.max_stats;
         ret->module_link = ctx.cfg.module_link;
         ret->readme = NULL;
         return ret;
 }
 
 struct cgit_repo *cgit_get_repoinfo(const char *url)
 {
         int i;
         struct cgit_repo *repo;
 
         for (i=0; i<cgit_repolist.count; i++) {
                 repo = &cgit_repolist.repos[i];
diff --git a/ui-shared.c b/ui-shared.c
index 0e688a0..97b9d46 100644
--- a/ui-shared.c
+++ b/ui-shared.c
@@ -632,25 +632,25 @@ void cgit_print_pageheader(struct cgit_context *ctx)
                 cgit_summary_link("summary", NULL, hc(cmd, "summary"),
                                   ctx->qry.head);
                 cgit_refs_link("refs", NULL, hc(cmd, "refs"), ctx->qry.head,
                                ctx->qry.sha1, NULL);
                 cgit_log_link("log", NULL, hc(cmd, "log"), ctx->qry.head,
                               NULL, NULL, 0, NULL, NULL);
                 cgit_tree_link("tree", NULL, hc(cmd, "tree"), ctx->qry.head,
                                ctx->qry.sha1, NULL);
                 cgit_commit_link("commit", NULL, hc(cmd, "commit"),
                                  ctx->qry.head, ctx->qry.sha1);
                 cgit_diff_link("diff", NULL, hc(cmd, "diff"), ctx->qry.head,
                                ctx->qry.sha1, ctx->qry.sha2, NULL);
-                if (ctx->repo->enable_stats)
+                if (ctx->repo->max_stats)
                         reporevlink("stats", "stats", NULL, hc(cmd, "stats"),
                                     ctx->qry.head, NULL, NULL);
                 if (ctx->repo->readme)
                         reporevlink("about", "about", NULL,
                                     hc(cmd, "about"), ctx->qry.head, NULL,
                                     NULL);
                 html("</td><td class='form'>");
                 html("<form class='right' method='get' action='");
                 if (ctx->cfg.virtual_root)
                         html_url_path(cgit_fileurl(ctx->qry.repo, "log",
                                                    ctx->qry.path, NULL));
                 html("'>\n");
diff --git a/ui-stats.c b/ui-stats.c
index 3cc8d70..1104485 100644
--- a/ui-stats.c
+++ b/ui-stats.c
@@ -1,35 +1,21 @@
+#include <string-list.h>
+
 #include "cgit.h"
 #include "html.h"
-#include <string-list.h>
+#include "ui-shared.h"
+#include "ui-stats.h"
 
 #define MONTHS 6
 
-struct Period {
-        const char code;
-        const char *name;
-        int max_periods;
-        int count;
-
-        /* Convert a tm value to the first day in the period */
-        void (*trunc)(struct tm *tm);
-
-        /* Update tm value to start of next/previous period */
-        void (*dec)(struct tm *tm);
-        void (*inc)(struct tm *tm);
-
-        /* Pretty-print a tm value */
-        char *(*pretty)(struct tm *tm);
-};
-
 struct authorstat {
         long total;
         struct string_list list;
 };
 
 #define DAY_SECS (60 * 60 * 24)
 #define WEEK_SECS (DAY_SECS * 7)
 
 static void trunc_week(struct tm *tm)
 {
         time_t t = timegm(tm);
         t -= ((tm->tm_wday + 6) % 7) * DAY_SECS;
@@ -128,33 +114,57 @@ static void dec_year(struct tm *tm)
 }
 
 static void inc_year(struct tm *tm)
 {
         tm->tm_year++;
 }
 
 static char *pretty_year(struct tm *tm)
 {
         return fmt("%d", tm->tm_year + 1900);
 }
 
-struct Period periods[] = {
+struct cgit_period periods[] = {
         {'w', "week", 12, 4, trunc_week, dec_week, inc_week, pretty_week},
         {'m', "month", 12, 4, trunc_month, dec_month, inc_month, pretty_month},
         {'q', "quarter", 12, 4, trunc_quarter, dec_quarter, inc_quarter, pretty_quarter},
         {'y', "year", 12, 4, trunc_year, dec_year, inc_year, pretty_year},
 };
 
+/* Given a period code or name, return a period index (1, 2, 3 or 4)
+ * and update the period pointer to the correcsponding struct.
+ * If no matching code is found, return 0.
+ */
+int cgit_find_stats_period(const char *expr, struct cgit_period **period)
+{
+        int i;
+        char code = '\0';
+
+        if (!expr)
+                return 0;
+
+        if (strlen(expr) == 1)
+                code = expr[0];
+
+        for (i = 0; i < sizeof(periods) / sizeof(periods[0]); i++)
+                if (periods[i].code == code || !strcmp(periods[i].name, expr)) {
+                        if (period)
+                                *period = &periods[i];
+                        return i+1;
+                }
+        return 0;
+}
+
 static void add_commit(struct string_list *authors, struct commit *commit,
-        struct Period *period)
+        struct cgit_period *period)
 {
         struct commitinfo *info;
         struct string_list_item *author, *item;
         struct authorstat *authorstat;
         struct string_list *items;
         char *tmp;
         struct tm *date;
         time_t t;
 
         info = cgit_parse_commit(commit);
         tmp = xstrdup(info->author);
         author = string_list_insert(tmp, authors);
@@ -181,25 +191,25 @@ static int cmp_total_commits(const void *a1, const void *a2)
         const struct string_list_item *i1 = a1;
         const struct string_list_item *i2 = a2;
         const struct authorstat *auth1 = i1->util;
         const struct authorstat *auth2 = i2->util;
 
         return auth2->total - auth1->total;
 }
 
 /* Walk the commit DAG and collect number of commits per author per
  * timeperiod into a nested string_list collection.
  */
 struct string_list collect_stats(struct cgit_context *ctx,
-        struct Period *period)
+        struct cgit_period *period)
 {
         struct string_list authors;
         struct rev_info rev;
         struct commit *commit;
         const char *argv[] = {NULL, ctx->qry.head, NULL, NULL, NULL, NULL};
         int argc = 3;
         time_t now;
         long i;
         struct tm *tm;
         char tmp[11];
 
         time(&now);
@@ -224,25 +234,25 @@ struct string_list collect_stats(struct cgit_context *ctx,
         prepare_revision_walk(&rev);
         memset(&authors, 0, sizeof(authors));
         while ((commit = get_revision(&rev)) != NULL) {
                 add_commit(&authors, commit, period);
                 free(commit->buffer);
                 free_commit_list(commit->parents);
         }
         return authors;
 }
 
 void print_combined_authorrow(struct string_list *authors, int from, int to,
         const char *name, const char *leftclass, const char *centerclass,
-        const char *rightclass, struct Period *period)
+        const char *rightclass, struct cgit_period *period)
 {
         struct string_list_item *author;
         struct authorstat *authorstat;
         struct string_list *items;
         struct string_list_item *date;
         time_t now;
         long i, j, total, subtotal;
         struct tm *tm;
         char *tmp;
 
         time(&now);
         tm = gmtime(&now);
@@ -262,25 +272,26 @@ void print_combined_authorrow(struct string_list *authors, int from, int to,
                         authorstat = author->util;
                         items = &authorstat->list;
                         date = string_list_lookup(tmp, items);
                         if (date)
                                 subtotal += (size_t)date->util;
                 }
                 htmlf("<td class='%s'>%d</td>", centerclass, subtotal);
                 total += subtotal;
         }
         htmlf("<td class='%s'>%d</td></tr>", rightclass, total);
 }
 
-void print_authors(struct string_list *authors, int top, struct Period *period)
+void print_authors(struct string_list *authors, int top,
+                   struct cgit_period *period)
 {
         struct string_list_item *author;
         struct authorstat *authorstat;
         struct string_list *items;
         struct string_list_item *date;
         time_t now;
         long i, j, total;
         struct tm *tm;
         char *tmp;
 
         time(&now);
         tm = gmtime(&now);
@@ -330,61 +341,69 @@ void print_authors(struct string_list *authors, int top, struct Period *period)
         print_combined_authorrow(authors, 0, authors->nr - 1, "Total",
                 "total", "sum", "sum", period);
         html("</table>");
 }
 
 /* Create a sorted string_list with one entry per author. The util-field
  * for each author is another string_list which is used to calculate the
  * number of commits per time-interval.
  */
 void cgit_show_stats(struct cgit_context *ctx)
 {
         struct string_list authors;
-        struct Period *period;
+        struct cgit_period *period;
         int top, i;
+        const char *code = "w";
 
-        period = &periods[0];
-        if (ctx->qry.period) {
-                for (i = 0; i < sizeof(periods) / sizeof(periods[0]); i++)
-                        if (periods[i].code == ctx->qry.period[0]) {
-                                period = &periods[i];
-                                break;
-                        }
+        if (ctx->qry.period)
+                code = ctx->qry.period;
+
+        i = cgit_find_stats_period(code, &period);
+        if (!i) {
+                cgit_print_error(fmt("Unknown statistics type: %c", code));
+                return;
+        }
+        if (i > ctx->repo->max_stats) {
+                cgit_print_error(fmt("Statistics type disabled: %s",
+                                     period->name));
+                return;
         }
         authors = collect_stats(ctx, period);
         qsort(authors.items, authors.nr, sizeof(struct string_list_item),
                 cmp_total_commits);
 
         top = ctx->qry.ofs;
         if (!top)
                 top = 10;
         htmlf("<h2>Commits per author per %s", period->name);
         if (ctx->qry.path) {
                 html(" (path '");
                 html_txt(ctx->qry.path);
                 html("')");
         }
         html("</h2>");
 
         html("<form method='get' action='.' style='float: right; text-align: right;'>");
         if (strcmp(ctx->qry.head, ctx->repo->defbranch))
                 htmlf("<input type='hidden' name='h' value='%s'/>", ctx->qry.head);
-        html("Period: ");
-        html("<select name='period' onchange='this.form.submit();'>");
-        for (i = 0; i < sizeof(periods) / sizeof(periods[0]); i++)
-                htmlf("<option value='%c'%s>%s</option>",
-                        periods[i].code,
-                        period == &periods[i] ? " selected" : "",
-                        periods[i].name);
-        html("</select><br/><br/>");
+        if (ctx->repo->max_stats > 1) {
+                html("Period: ");
+                html("<select name='period' onchange='this.form.submit();'>");
+                for (i = 0; i < ctx->repo->max_stats; i++)
+                        htmlf("<option value='%c'%s>%s</option>",
+                                periods[i].code,
+                                period == &periods[i] ? " selected" : "",
+                                periods[i].name);
+                html("</select><br/><br/>");
+        }
         html("Authors: ");
         html("");
         html("<select name='ofs' onchange='this.form.submit();'>");
         htmlf("<option value='10'%s>10</option>", top == 10 ? " selected" : "");
         htmlf("<option value='25'%s>25</option>", top == 25 ? " selected" : "");
         htmlf("<option value='50'%s>50</option>", top == 50 ? " selected" : "");
         htmlf("<option value='100'%s>100</option>", top == 100 ? " selected" : "");
         htmlf("<option value='-1'%s>All</option>", top == -1 ? " selected" : "");
         html("</select>");
         html("<noscript>&nbsp;&nbsp;<input type='submit' value='Reload'/></noscript>");
         html("</form>");
         print_authors(&authors, top, period);
diff --git a/ui-stats.h b/ui-stats.h
index f1d744c..4f13dba 100644
--- a/ui-stats.h
+++ b/ui-stats.h
@@ -1,8 +1,27 @@
 #ifndef UI_STATS_H
 #define UI_STATS_H
 
 #include "cgit.h"
 
+struct cgit_period {
+        const char code;
+        const char *name;
+        int max_periods;
+        int count;
+
+        /* Convert a tm value to the first day in the period */
+        void (*trunc)(struct tm *tm);
+
+        /* Update tm value to start of next/previous period */
+        void (*dec)(struct tm *tm);
+        void (*inc)(struct tm *tm);
+
+        /* Pretty-print a tm value */
+        char *(*pretty)(struct tm *tm);
+};
+
+extern int cgit_find_stats_period(const char *expr, struct cgit_period **period);
+
 extern void cgit_show_stats(struct cgit_context *ctx);
 
 #endif /* UI_STATS_H */