Change types for source map offsets (#174)

* Improve strbuf guarantees

Introduce BUFSIZE_MAX macro and make sure that the strbuf implementation
can handle strings up to this size.

* Abort early if document size exceeds internal limit

* Change types for source map offsets

Switch to size_t for the public API, making the public headers
C89-compatible again.

Switch to bufsize_t internally, reducing memory usage and improving
performance on 32-bit platforms.

* Make parser return NULL on internal index overflow

Make S_parser_feed set an error and ignore subsequent chunks if the
total input document size exceeds an internal limit. Make
cmark_parser_finish return NULL if an error was encountered. Add
public API functions to retrieve error code and error message.

strbuf overflow in renderers and OOM in parser or renderers still
cause an abort.

1 files changed, 24 insertions, 8 deletions

diff --git a/src/cmark.h b/src/cmark.h
index 034f0e6..5ce6d10 100644
--- a/src/cmark.h
+++ b/src/cmark.h
@@ -2,7 +2,6 @@
 #define CMARK_H
 
 #include <stdio.h>
-#include <stdint.h>
 #include <cmark_export.h>
 #include <cmark_version.h>
 
@@ -23,7 +22,7 @@ extern "C" {
 /** Convert 'text' (assumed to be a UTF-8 encoded string with length
  * 'len') from CommonMark Markdown to HTML, returning a null-terminated,
  * UTF-8-encoded string. It is the caller's responsibility
- * to free the returned buffer.
+ * to free the returned buffer. Returns NULL on error.
  */
 CMARK_EXPORT
 char *cmark_markdown_to_html(const char *text, size_t len, int options);
@@ -99,6 +98,12 @@ typedef enum {
   CMARK_PAREN_DELIM
 } cmark_delim_type;
 
+typedef enum {
+  CMARK_ERR_NONE,
+  CMARK_ERR_OUT_OF_MEMORY,
+  CMARK_ERR_INPUT_TOO_LARGE
+} cmark_err_type;
+
 typedef struct cmark_node cmark_node;
 typedef struct cmark_parser cmark_parser;
 typedef struct cmark_iter cmark_iter;
@@ -489,12 +494,22 @@ cmark_parser *cmark_parser_new_with_mem(int options, cmark_mem *mem);
 CMARK_EXPORT
 void cmark_parser_free(cmark_parser *parser);
 
+/** Return the error code after a failed operation.
+ */
+CMARK_EXPORT
+cmark_err_type cmark_parser_get_error(cmark_parser *parser);
+
+/** Return the error code after a failed operation.
+ */
+CMARK_EXPORT
+const char *cmark_parser_get_error_message(cmark_parser *parser);
+
 /** Feeds a string of length 'len' to 'parser'.
  */
 CMARK_EXPORT
 void cmark_parser_feed(cmark_parser *parser, const char *buffer, size_t len);
 
-/** Finish parsing and return a pointer to a tree of nodes.
+/** Finish parsing and return a pointer to a tree of nodes or NULL on error.
  */
 CMARK_EXPORT
 cmark_node *cmark_parser_finish(cmark_parser *parser);
@@ -507,7 +522,7 @@ cmark_source_extent *cmark_parser_get_first_source_extent(cmark_parser *parser);
 /** Parse a CommonMark document in 'buffer' of length 'len'.
  * Returns a pointer to a tree of nodes.  The memory allocated for
  * the node tree should be released using 'cmark_node_free'
- * when it is no longer needed.
+ * when it is no longer needed.  Returns NULL on error.
  */
 CMARK_EXPORT
 cmark_node *cmark_parse_document(const char *buffer, size_t len, int options);
@@ -515,22 +530,23 @@ cmark_node *cmark_parse_document(const char *buffer, size_t len, int options);
 /** Parse a CommonMark document in file 'f', returning a pointer to
  * a tree of nodes.  The memory allocated for the node tree should be
  * released using 'cmark_node_free' when it is no longer needed.
+ * Returns NULL on error.
  */
 CMARK_EXPORT
 cmark_node *cmark_parse_file(FILE *f, int options);
 
-/** 
+/**
  * ## Source map API
  */
 
 /* Return the index, in bytes, of the start of this extent */
 CMARK_EXPORT
-uint64_t cmark_source_extent_get_start(cmark_source_extent *extent);
+size_t cmark_source_extent_get_start(cmark_source_extent *extent);
 
-/* Return the index, in bytes, of the stop of this extent. This 
+/* Return the index, in bytes, of the stop of this extent. This
  * index is not included in the extent*/
 CMARK_EXPORT
-uint64_t cmark_source_extent_get_stop(cmark_source_extent *extent);
+size_t cmark_source_extent_get_stop(cmark_source_extent *extent);
 
 /* Return the extent immediately following 'extent' */
 CMARK_EXPORT