[PATCH] Simplify date handling and make it more reliable
[git/git.git] / commit-tree.c
index ac431fe..50fe196 100644 (file)
@@ -7,6 +7,9 @@
 
 #include <pwd.h>
 #include <time.h>
+#include <string.h>
+#include <ctype.h>
+#include <time.h>
 
 #define BLOCKING (1ul << 14)
 #define ORIG_OFFSET (40)
@@ -95,6 +98,148 @@ static void remove_special(char *p)
        }
 }
 
+static const char *month_names[] = {
+        "Jan", "Feb", "Mar", "Apr", "May", "Jun",
+        "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"
+};
+
+static const char *weekday_names[] = {
+        "Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"
+};
+
+
+static char *skipfws(char *str)
+{
+       while (isspace(*str))
+               str++;
+       return str;
+}
+
+       
+/* Gr. strptime is crap for this; it doesn't have a way to require RFC2822
+   (i.e. English) day/month names, and it doesn't work correctly with %z. */
+static void parse_rfc2822_date(char *date, char *result, int maxlen)
+{
+       struct tm tm;
+       char *p;
+       int i, offset;
+       time_t then;
+
+       memset(&tm, 0, sizeof(tm));
+
+       /* Skip day-name */
+       p = skipfws(date);
+       if (!isdigit(*p)) {
+               for (i=0; i<7; i++) {
+                       if (!strncmp(p,weekday_names[i],3) && p[3] == ',') {
+                               p = skipfws(p+4);
+                               goto day;
+                       }
+               }
+               return;
+       }                                       
+
+       /* day */
+ day:
+       tm.tm_mday = strtoul(p, &p, 10);
+
+       if (tm.tm_mday < 1 || tm.tm_mday > 31)
+               return;
+
+       if (!isspace(*p))
+               return;
+
+       p = skipfws(p);
+
+       /* month */
+
+       for (i=0; i<12; i++) {
+               if (!strncmp(p, month_names[i], 3) && isspace(p[3])) {
+                       tm.tm_mon = i;
+                       p = skipfws(p+strlen(month_names[i]));
+                       goto year;
+               }
+       }
+       return; /* Error -- bad month */
+
+       /* year */
+ year: 
+       tm.tm_year = strtoul(p, &p, 10);
+
+       if (!tm.tm_year && !isspace(*p))
+               return;
+
+       if (tm.tm_year > 1900)
+               tm.tm_year -= 1900;
+               
+       p=skipfws(p);
+
+       /* hour */
+       if (!isdigit(*p))
+               return;
+       tm.tm_hour = strtoul(p, &p, 10);
+       
+       if (!tm.tm_hour > 23)
+               return;
+
+       if (*p != ':')
+               return; /* Error -- bad time */
+       p++;
+
+       /* minute */
+       if (!isdigit(*p))
+               return;
+       tm.tm_min = strtoul(p, &p, 10);
+       
+       if (!tm.tm_min > 59)
+               return;
+
+       if (isspace(*p))
+               goto zone;
+
+       if (*p != ':')
+               return; /* Error -- bad time */
+       p++;
+
+       /* second */
+       if (!isdigit(*p))
+               return;
+       tm.tm_sec = strtoul(p, &p, 10);
+       
+       if (!tm.tm_sec > 59)
+               return;
+
+       if (!isspace(*p))
+               return;
+
+ zone:
+       p = skipfws(p);
+
+       if (*p == '-')
+               offset = -60;
+       else if (*p == '+')
+               offset = 60;
+       else
+              return;
+
+       if (!isdigit(p[1]) || !isdigit(p[2]) || !isdigit(p[3]) || !isdigit(p[4]))
+               return;
+
+       i = strtoul(p+1, NULL, 10);
+       offset *= ((i % 100) + ((i / 100) * 60));
+
+       if (*(skipfws(p + 5)))
+               return;
+
+       then = mktime(&tm); /* mktime appears to ignore the GMT offset, stupidly */
+       if (then == -1)
+               return;
+
+       then -= offset;
+
+       snprintf(result, maxlen, "%lu %5.5s", then, p);
+}
+
 /*
  * Having more than two parents may be strange, but hey, there's
  * no conceptual reason why the file format couldn't accept multi-way
@@ -114,10 +259,12 @@ int main(int argc, char **argv)
        unsigned char commit_sha1[20];
        char *gecos, *realgecos;
        char *email, realemail[1000];
-       char *date, *realdate;
+       char date[20], realdate[20];
+       char *audate;
        char comment[1000];
        struct passwd *pw;
        time_t now;
+       struct tm *tm;
        char *buffer;
        unsigned int size;
 
@@ -142,15 +289,19 @@ int main(int argc, char **argv)
        realemail[len] = '@';
        gethostname(realemail+len+1, sizeof(realemail)-len-1);
        time(&now);
-       realdate = ctime(&now);
+       tm = localtime(&now);
+
+       strftime(realdate, sizeof(realdate), "%s %z", tm);
+       strcpy(date, realdate);
 
        gecos = getenv("AUTHOR_NAME") ? : realgecos;
        email = getenv("AUTHOR_EMAIL") ? : realemail;
-       date = getenv("AUTHOR_DATE") ? : realdate;
+       audate = getenv("AUTHOR_DATE");
+       if (audate)
+               parse_rfc2822_date(audate, date, sizeof(date));
 
        remove_special(gecos); remove_special(realgecos);
        remove_special(email); remove_special(realemail);
-       remove_special(date); remove_special(realdate);
 
        init_buffer(&buffer, &size);
        add_buffer(&buffer, &size, "tree %s\n", sha1_to_hex(tree_sha1));