strbuf: add strbuf_read_once to read without blocking

diff --git a/strbuf.h b/strbuf.h
index 5397d91d7ade0360077c3b2ceb9e6d3cd226820d..2bf90e70fcf1e9bcbfcbfdf4bc8b30e1d7b61d10 100644 (file)
--- a/strbuf.h
+++ b/strbuf.h
@@ -366,6 +366,14 @@ extern size_t strbuf_fread(struct strbuf *, size_t, FILE *);
  */
 extern ssize_t strbuf_read(struct strbuf *, int fd, size_t hint);
 
+/**
+ * Read the contents of a given file descriptor partially by using only one
+ * attempt of xread. The third argument can be used to give a hint about the
+ * file size, to avoid reallocs. Returns the number of new bytes appended to
+ * the sb.
+ */
+extern ssize_t strbuf_read_once(struct strbuf *, int fd, size_t hint);
+
 /**
  * Read the contents of a file, specified by its path. The third argument
  * can be used to give a hint about the file size, to avoid reallocs.
@@ -483,6 +491,14 @@ static inline struct strbuf **strbuf_split(const struct strbuf *sb,
  */
 extern void strbuf_list_free(struct strbuf **);
 
+/**
+ * Add the abbreviation, as generated by find_unique_abbrev, of `sha1` to
+ * the strbuf `sb`.
+ */
+extern void strbuf_add_unique_abbrev(struct strbuf *sb,
+                                    const unsigned char *sha1,
+                                    int abbrev_len);
+
 /**
  * Launch the user preferred editor to edit a file and fill the buffer
  * with the file's contents upon the user completing their editing. The
@@ -500,10 +516,21 @@ extern void strbuf_add_lines(struct strbuf *sb, const char *prefix, const char *
  */
 extern void strbuf_addstr_xml_quoted(struct strbuf *sb, const char *s);
 
+/**
+ * "Complete" the contents of `sb` by ensuring that either it ends with the
+ * character `term`, or it is empty.  This can be used, for example,
+ * to ensure that text ends with a newline, but without creating an empty
+ * blank line if there is no content in the first place.
+ */
+static inline void strbuf_complete(struct strbuf *sb, char term)
+{
+       if (sb->len && sb->buf[sb->len - 1] != term)
+               strbuf_addch(sb, term);
+}
+
 static inline void strbuf_complete_line(struct strbuf *sb)
 {
-       if (sb->len && sb->buf[sb->len - 1] != '\n')
-               strbuf_addch(sb, '\n');
+       strbuf_complete(sb, '\n');
 }
 
 extern int strbuf_branchname(struct strbuf *sb, const char *name);