diff_unique_abbrev: rename to diff_aligned_abbrev

The word "align" describes how the function actually differs
from find_unique_abbrev, and will make it less confusing
when we add more diff-specific abbrevation functions that do
not do this alignment.

Since this is a globally available function, let's also move
its descriptive comment to the header file, where we
typically document function interfaces.
Signed-off-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

combine-diff.c

@@ -1203,9 +1203,9 @@ static void show_raw_diff(struct combine_diff_path *p, int num_parent, struct re
 
 		/* Show sha1's */
 		for (i = 0; i < num_parent; i++)
-			printf(" %s", diff_unique_abbrev(p->parent[i].oid.hash,
-							 opt->abbrev));
-		printf(" %s ", diff_unique_abbrev(p->oid.hash, opt->abbrev));
+			printf(" %s", diff_aligned_abbrev(p->parent[i].oid.hash,
+							  opt->abbrev));
+		printf(" %s ", diff_aligned_abbrev(p->oid.hash, opt->abbrev));
 	}
 
 	if (opt->output_format & (DIFF_FORMAT_RAW | DIFF_FORMAT_NAME_STATUS)) {

diff.c

@@ -4157,11 +4157,7 @@ void diff_free_filepair(struct diff_filepair *p)
 	free(p);
 }
 
-/*
- * This is different from find_unique_abbrev() in that
- * it stuffs the result with dots for alignment.
- */
-const char *diff_unique_abbrev(const unsigned char *sha1, int len)
+const char *diff_aligned_abbrev(const unsigned char *sha1, int len)
 {
 	int abblen;
 	const char *abbrev;
@@ -4209,9 +4205,9 @@ static void diff_flush_raw(struct diff_filepair *p, struct diff_options *opt)
 	fprintf(opt->file, "%s", diff_line_prefix(opt));
 	if (!(opt->output_format & DIFF_FORMAT_NAME_STATUS)) {
 		fprintf(opt->file, ":%06o %06o %s ", p->one->mode, p->two->mode,
-			diff_unique_abbrev(p->one->oid.hash, opt->abbrev));
+			diff_aligned_abbrev(p->one->oid.hash, opt->abbrev));
 		fprintf(opt->file, "%s ",
-			diff_unique_abbrev(p->two->oid.hash, opt->abbrev));
+			diff_aligned_abbrev(p->two->oid.hash, opt->abbrev));
 	}
 	if (p->score) {
 		fprintf(opt->file, "%c%03d%c", p->status, similarity_index(p),

diff.h

@@ -340,7 +340,11 @@ extern void diff_warn_rename_limit(const char *varname, int needed, int degraded
 #define DIFF_STATUS_FILTER_AON		'*'
 #define DIFF_STATUS_FILTER_BROKEN	'B'
 
-extern const char *diff_unique_abbrev(const unsigned char *, int);
+/*
+ * This is different from find_unique_abbrev() in that
+ * it stuffs the result with dots for alignment.
+ */
+extern const char *diff_aligned_abbrev(const unsigned char *sha1, int);
 
 /* do not report anything on removed paths */
 #define DIFF_SILENT_ON_REMOVED 01