Abort on strbuf errors

Users of the strbuf API are supposed to check for an OOM condition
after appending to strbufs, but:

* This is never done in the whole code base.
* The implementation was flawed because only `ptr` was set to the
  OOM value without adjusting `size` and `asize`. After an error,
  subsequent calls could very well lead to segfaults, contrary to the
  documentation.

Change the code to always abort on errors with a message printed to
stderr. The only alternative is to propagate errors throughout the
whole library which seems infeasible.

1 files changed, 9 insertions, 47 deletions

diff --git a/src/buffer.h b/src/buffer.h
index fb9f910..417df26 100644
--- a/src/buffer.h
+++ b/src/buffer.h
@@ -16,8 +16,6 @@ typedef struct {
 
 extern unsigned char cmark_strbuf__initbuf[];
 
-extern unsigned char cmark_strbuf__oom[];
-
 #define GH_BUF_INIT { cmark_strbuf__initbuf, 0, 0 }
 
 /**
@@ -29,41 +27,13 @@ extern unsigned char cmark_strbuf__oom[];
 void cmark_strbuf_init(cmark_strbuf *buf, int initial_size);
 
 /**
- * Attempt to grow the buffer to hold at least `target_size` bytes.
- *
- * If the allocation fails, this will return an error.  If mark_oom is true,
- * this will mark the buffer as invalid for future operations; if false,
- * existing buffer content will be preserved, but calling code must handle
- * that buffer was not expanded.
- */
-int cmark_strbuf_try_grow(cmark_strbuf *buf, int target_size, bool mark_oom);
-
-/**
  * Grow the buffer to hold at least `target_size` bytes.
- *
- * If the allocation fails, this will return an error and the buffer will be
- * marked as invalid for future operations, invaliding contents.
- *
- * @return 0 on success or -1 on failure
  */
-int cmark_strbuf_grow(cmark_strbuf *buf, int target_size);
+void cmark_strbuf_grow(cmark_strbuf *buf, int target_size);
 
 void cmark_strbuf_free(cmark_strbuf *buf);
 void cmark_strbuf_swap(cmark_strbuf *buf_a, cmark_strbuf *buf_b);
 
-/**
- * Test if there have been any reallocation failures with this cmark_strbuf.
- *
- * Any function that writes to a cmark_strbuf can fail due to memory allocation
- * issues.  If one fails, the cmark_strbuf will be marked with an OOM error and
- * further calls to modify the buffer will fail.  Check cmark_strbuf_oom() at the
- * end of your sequence and it will be true if you ran out of memory at any
- * point with that buffer.
- *
- * @return false if no error, true if allocation error
- */
-bool cmark_strbuf_oom(const cmark_strbuf *buf);
-
 size_t cmark_strbuf_len(const cmark_strbuf *buf);
 
 int cmark_strbuf_cmp(const cmark_strbuf *a, const cmark_strbuf *b);
@@ -79,22 +49,14 @@ static inline const char *cmark_strbuf_cstr(const cmark_strbuf *buf)
 
 #define cmark_strbuf_at(buf, n) ((buf)->ptr[n])
 
-/*
- * Functions below that return int value error codes will return 0 on
- * success or -1 on failure (which generally means an allocation failed).
- * Using a cmark_strbuf where the allocation has failed with result in -1 from
- * all further calls using that buffer.  As a result, you can ignore the
- * return code of these functions and call them in a series then just call
- * cmark_strbuf_oom at the end.
- */
-int cmark_strbuf_set(cmark_strbuf *buf, const unsigned char *data, int len);
-int cmark_strbuf_sets(cmark_strbuf *buf, const char *string);
-int cmark_strbuf_putc(cmark_strbuf *buf, int c);
-int cmark_strbuf_put(cmark_strbuf *buf, const unsigned char *data, int len);
-int cmark_strbuf_puts(cmark_strbuf *buf, const char *string);
-int cmark_strbuf_printf(cmark_strbuf *buf, const char *format, ...)
-CMARK_ATTRIBUTE((format (printf, 2, 3)));
-int cmark_strbuf_vprintf(cmark_strbuf *buf, const char *format, va_list ap);
+void cmark_strbuf_set(cmark_strbuf *buf, const unsigned char *data, int len);
+void cmark_strbuf_sets(cmark_strbuf *buf, const char *string);
+void cmark_strbuf_putc(cmark_strbuf *buf, int c);
+void cmark_strbuf_put(cmark_strbuf *buf, const unsigned char *data, int len);
+void cmark_strbuf_puts(cmark_strbuf *buf, const char *string);
+void cmark_strbuf_printf(cmark_strbuf *buf, const char *format, ...)
+	CMARK_ATTRIBUTE((format (printf, 2, 3)));
+void cmark_strbuf_vprintf(cmark_strbuf *buf, const char *format, va_list ap);
 void cmark_strbuf_clear(cmark_strbuf *buf);
 
 int cmark_strbuf_strchr(const cmark_strbuf *buf, int c, int pos);