date: make it a proper `git_date` utility class

Instead of `git__date`, just use `git_date`.

src/date.c

@@ -857,7 +857,7 @@ static git_time_t approxidate_str(const char *date,
 	return update_tm(&tm, &now, 0);
 }
 
-int git__date_parse(git_time_t *out, const char *date)
+int git_date_parse(git_time_t *out, const char *date)
 {
 	time_t time_sec;
 	git_time_t timestamp;
@@ -875,7 +875,7 @@ int git__date_parse(git_time_t *out, const char *date)
    return error_ret;
 }
 
-int git__date_rfc2822_fmt(char *out, size_t len, const git_time *date)
+int git_date_rfc2822_fmt(char *out, size_t len, const git_time *date)
 {
 	int written;
 	struct tm gmt;

src/date.h

+/*
+ * Copyright (C) the libgit2 contributors. All rights reserved.
+ *
+ * This file is part of libgit2, distributed under the GNU GPL v2 with
+ * a Linking Exception. For full terms see the included COPYING file.
+ */
+#ifndef INCLUDE_date_h__
+#define INCLUDE_date_h__
+
+#include "util.h"
+#include "str.h"
+
+/*
+ * Parse a string into a value as a git_time_t.
+ *
+ * Sample valid input:
+ * - "yesterday"
+ * - "July 17, 2003"
+ * - "2003-7-17 08:23"
+ */
+extern int git_date_parse(git_time_t *out, const char *date);
+
+/*
+ * Format a git_time as a RFC2822 string
+ *
+ * @param out buffer to store formatted date; a '\\0' terminator will automatically be added.
+ * @param len size of the buffer; should be atleast `GIT_DATE_RFC2822_SZ` in size;
+ * @param date the date to be formatted
+ * @return 0 if successful; -1 on error
+ */
+extern int git_date_rfc2822_fmt(char *out, size_t len, const git_time *date);
+
+#endif

src/email.c

@@ -12,6 +12,7 @@
 #include "diff_generate.h"
 #include "diff_stats.h"
 #include "patch.h"
+#include "date.h"
 
 #include "git2/email.h"
 #include "git2/patch.h"
@@ -123,7 +124,7 @@ static int append_header(
 	if ((error = git_oid_fmt(id, commit_id)) < 0 ||
 	    (error = git_str_printf(out, "From %.*s %s\n", GIT_OID_HEXSZ, id, EMAIL_TIMESTAMP)) < 0 ||
 	    (error = git_str_printf(out, "From: %s <%s>\n", author->name, author->email)) < 0 ||
-	    (error = git__date_rfc2822_fmt(date, sizeof(date), &author->when)) < 0 ||
+	    (error = git_date_rfc2822_fmt(date, sizeof(date), &author->when)) < 0 ||
 	    (error = git_str_printf(out, "Date: %s\n", date)) < 0 ||
 	    (error = append_subject(out, patch_idx, patch_count, summary, opts)) < 0)
 		return error;

src/revparse.c

@@ -11,6 +11,7 @@
 #include "tree.h"
 #include "refdb.h"
 #include "regexp.h"
+#include "date.h"
 
 #include "git2.h"
 
@@ -344,7 +345,7 @@ static int handle_at_syntax(git_object **out, git_reference **ref, const char *s
 		goto cleanup;
 	}
 
-	if (git__date_parse(&timestamp, curly_braces_content) < 0)
+	if (git_date_parse(&timestamp, curly_braces_content) < 0)
 		goto cleanup;
 
 	error = retrieve_revobject_from_reflog(out, ref, repo, git_str_cstr(&identifier), (size_t)timestamp);

src/util.h

@@ -295,26 +295,6 @@ GIT_INLINE(bool) git__isxdigit(int c)
 extern int git__parse_bool(int *out, const char *value);
 
 /*
- * Parse a string into a value as a git_time_t.
- *
- * Sample valid input:
- * - "yesterday"
- * - "July 17, 2003"
- * - "2003-7-17 08:23"
- */
-extern int git__date_parse(git_time_t *out, const char *date);
-
-/*
- * Format a git_time as a RFC2822 string
- *
- * @param out buffer to store formatted date; a '\\0' terminator will automatically be added.
- * @param len size of the buffer; should be atleast `GIT_DATE_RFC2822_SZ` in size;
- * @param date the date to be formatted
- * @return 0 if successful; -1 on error
- */
-extern int git__date_rfc2822_fmt(char *out, size_t len, const git_time *date);
-
-/*
  * Unescapes a string in-place.
  *
  * Edge cases behavior:

tests/date/date.c

 #include "clar_libgit2.h"
 
-#include "util.h"
+#include "date.h"
 
 void test_date_date__overflow(void)
 {
@@ -8,8 +8,8 @@ void test_date_date__overflow(void)
    git_time_t d2038, d2039;
 
    /* This is expected to fail on a 32-bit machine. */
-   cl_git_pass(git__date_parse(&d2038, "2038-1-1"));
-   cl_git_pass(git__date_parse(&d2039, "2039-1-1"));
+   cl_git_pass(git_date_parse(&d2038, "2038-1-1"));
+   cl_git_pass(git_date_parse(&d2039, "2039-1-1"));
    cl_assert(d2038 < d2039);
 #endif
 }

tests/date/rfc2822.c

 #include "clar_libgit2.h"
 
-#include "util.h"
+#include "date.h"
 
 void test_date_rfc2822__format_rfc2822_no_offset(void)
 {
 	git_time t = {1397031663, 0};
 	char buf[GIT_DATE_RFC2822_SZ];
 
-	cl_git_pass(git__date_rfc2822_fmt(buf, sizeof(buf), &t));
+	cl_git_pass(git_date_rfc2822_fmt(buf, sizeof(buf), &t));
 	cl_assert(strcmp(buf, "Wed, 9 Apr 2014 08:21:03 +0000") == 0);
 }
 
@@ -16,7 +16,7 @@ void test_date_rfc2822__format_rfc2822_positive_offset(void)
 	git_time t = {1397031663, 120};
 	char buf[GIT_DATE_RFC2822_SZ];
 
-	cl_git_pass(git__date_rfc2822_fmt(buf, sizeof(buf), &t));
+	cl_git_pass(git_date_rfc2822_fmt(buf, sizeof(buf), &t));
 	cl_assert(strcmp(buf, "Wed, 9 Apr 2014 10:21:03 +0200") == 0);
 }
 
@@ -25,7 +25,7 @@ void test_date_rfc2822__format_rfc2822_negative_offset(void)
 	git_time t = {1397031663, -120};
 	char buf[GIT_DATE_RFC2822_SZ];
 
-	cl_git_pass(git__date_rfc2822_fmt(buf, sizeof(buf), &t));
+	cl_git_pass(git_date_rfc2822_fmt(buf, sizeof(buf), &t));
 	cl_assert(strcmp(buf, "Wed, 9 Apr 2014 06:21:03 -0200") == 0);
 }
 
@@ -35,6 +35,6 @@ void test_date_rfc2822__format_rfc2822_buffer_too_small(void)
 	git_time t = {1397031663 + 86400, 0};
 	char buf[GIT_DATE_RFC2822_SZ-1];
 
-	cl_git_fail(git__date_rfc2822_fmt(buf, sizeof(buf), &t));
+	cl_git_fail(git_date_rfc2822_fmt(buf, sizeof(buf), &t));
 }