timestamp_t: a new data type for timestamps

Git's source code assumes that unsigned long is at least as precise as
time_t. Which is incorrect, and causes a lot of problems, in particular
where unsigned long is only 32-bit (notably on Windows, even in 64-bit
versions).

So let's just use a more appropriate data type instead. In preparation
for this, we introduce the new `timestamp_t` data type.

By necessity, this is a very, very large patch, as it has to replace all
timestamps' data type in one go.

As we will use a data type that is not necessarily identical to `time_t`,
we need to be very careful to use `time_t` whenever we interact with the
system functions, and `timestamp_t` everywhere else.

Signed-off-by: Johannes Schindelin <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: dscho

Documentation/technical/api-parse-options.txt

@@ -183,13 +183,13 @@ There are some macros to easily define options:
 	scale the provided value by 1024, 1024^2 or 1024^3 respectively.
 	The scaled value is put into `unsigned_long_var`.
 
-`OPT_DATE(short, long, &int_var, description)`::
+`OPT_DATE(short, long, &timestamp_t_var, description)`::
 	Introduce an option with date argument, see `approxidate()`.
-	The timestamp is put into `int_var`.
+	The timestamp is put into `timestamp_t_var`.
 
-`OPT_EXPIRY_DATE(short, long, &int_var, description)`::
+`OPT_EXPIRY_DATE(short, long, &timestamp_t_var, description)`::
 	Introduce an option with expiry date argument, see `parse_expiry_date()`.
-	The timestamp is put into `int_var`.
+	The timestamp is put into `timestamp_t_var`.
 
 `OPT_CALLBACK(short, long, &var, arg_str, description, func_ptr)`::
 	Introduce an option with argument.

archive-tar.c

@@ -27,9 +27,12 @@ static int write_tar_filter_archive(const struct archiver *ar,
  */
 #if ULONG_MAX == 0xFFFFFFFF
 #define USTAR_MAX_SIZE ULONG_MAX
-#define USTAR_MAX_MTIME ULONG_MAX
 #else
-#define USTAR_MAX_SIZE 077777777777UL
+#define USTAR_MAX_SIZE 077777777777ULL
+#endif
+#if TIME_MAX == 0xFFFFFFFF
+#define USTAR_MAX_MTIME TIME_MAX
+#else
 #define USTAR_MAX_MTIME 077777777777UL
 #endif
 

archive-zip.c

@@ -545,9 +545,17 @@ static void write_zip_trailer(const unsigned char *sha1)
 		write_or_die(1, sha1_to_hex(sha1), GIT_SHA1_HEXSZ);
 }
 
-static void dos_time(time_t *time, int *dos_date, int *dos_time)
+static void dos_time(timestamp_t *timestamp, int *dos_date, int *dos_time)
 {
-	struct tm *t = localtime(time);
+	time_t time;
+	struct tm *t;
+
+	if (date_overflows(*timestamp))
+		die("timestamp too large for this system: %"PRItime,
+		    *timestamp);
+	time = (time_t)*timestamp;
+	t = localtime(&time);
+	*timestamp = time;
 
 	*dos_date = t->tm_mday + (t->tm_mon + 1) * 32 +
 	            (t->tm_year + 1900 - 1980) * 512;

archive.h

@@ -9,7 +9,7 @@ struct archiver_args {
 	struct tree *tree;
 	const unsigned char *commit_sha1;
 	const struct commit *commit;
-	time_t time;
+	timestamp_t time;
 	struct pathspec pathspec;
 	unsigned int verbose : 1;
 	unsigned int worktree_attributes : 1;

builtin/am.c

@@ -877,7 +877,7 @@ static int hg_patch_to_mail(FILE *out, FILE *in, int keep_cr)
 		if (skip_prefix(sb.buf, "# User ", &str))
 			fprintf(out, "From: %s\n", str);
 		else if (skip_prefix(sb.buf, "# Date ", &str)) {
-			unsigned long timestamp;
+			timestamp_t timestamp;
 			long tz, tz2;
 			char *end;
 

builtin/blame.c

@@ -1561,13 +1561,13 @@ static void pass_blame(struct scoreboard *sb, struct origin *origin, int opt)
 struct commit_info {
 	struct strbuf author;
 	struct strbuf author_mail;
-	unsigned long author_time;
+	timestamp_t author_time;
 	struct strbuf author_tz;
 
 	/* filled only when asked for details */
 	struct strbuf committer;
 	struct strbuf committer_mail;
-	unsigned long committer_time;
+	timestamp_t committer_time;
 	struct strbuf committer_tz;
 
 	struct strbuf summary;
@@ -1578,7 +1578,7 @@ struct commit_info {
  */
 static void get_ac_line(const char *inbuf, const char *what,
 	struct strbuf *name, struct strbuf *mail,
-	unsigned long *time, struct strbuf *tz)
+	timestamp_t *time, struct strbuf *tz)
 {
 	struct ident_split ident;
 	size_t len, maillen, namelen;
@@ -1837,7 +1837,7 @@ static void assign_blame(struct scoreboard *sb, int opt)
 	stop_progress(&pi.progress);
 }
 
-static const char *format_time(unsigned long time, const char *tz_str,
+static const char *format_time(timestamp_t time, const char *tz_str,
 			       int show_raw_time)
 {
 	static struct strbuf time_buf = STRBUF_INIT;

builtin/fsck.c

@@ -397,7 +397,7 @@ static int fsck_obj_buffer(const unsigned char *sha1, enum object_type type,
 static int default_refs;
 
 static void fsck_handle_reflog_oid(const char *refname, struct object_id *oid,
-	unsigned long timestamp)
+	timestamp_t timestamp)
 {
 	struct object *obj;
 
@@ -418,7 +418,7 @@ static void fsck_handle_reflog_oid(const char *refname, struct object_id *oid,
 }
 
 static int fsck_handle_reflog_ent(struct object_id *ooid, struct object_id *noid,
-		const char *email, unsigned long timestamp, int tz,
+		const char *email, timestamp_t timestamp, int tz,
 		const char *message, void *cb_data)
 {
 	const char *refname = cb_data;

builtin/gc.c

@@ -33,7 +33,7 @@ static int aggressive_window = 250;
 static int gc_auto_threshold = 6700;
 static int gc_auto_pack_limit = 50;
 static int detach_auto = 1;
-static unsigned long gc_log_expire_time;
+static timestamp_t gc_log_expire_time;
 static const char *gc_log_expire = "1.day.ago";
 static const char *prune_expire = "2.weeks.ago";
 static const char *prune_worktrees_expire = "3.months.ago";

builtin/log.c

@@ -911,7 +911,7 @@ static void gen_message_id(struct rev_info *info, char *base)
 {
 	struct strbuf buf = STRBUF_INIT;
 	strbuf_addf(&buf, "%s.%"PRItime".git.%s", base,
-		    (unsigned long) time(NULL),
+		    (timestamp_t) time(NULL),
 		    git_committer_info(IDENT_NO_NAME|IDENT_NO_DATE|IDENT_STRICT));
 	info->message_id = strbuf_detach(&buf, NULL);
 }

builtin/merge-base.c

@@ -132,7 +132,7 @@ static void add_one_commit(struct object_id *oid, struct rev_collect *revs)
 }
 
 static int collect_one_reflog_ent(struct object_id *ooid, struct object_id *noid,
-				  const char *ident, unsigned long timestamp,
+				  const char *ident, timestamp_t timestamp,
 				  int tz, const char *message, void *cbdata)
 {
 	struct rev_collect *revs = cbdata;