dynbuf: introduce internal generic dynamic buffer functions

A common set of functions instead of many separate implementations for
creating buffers that can grow when appending data to them. Existing
functionality has been ported over.

In my early basic testing, the total number of allocations seem at
roughly the same amount as before, possibly a few less.

See docs/DYNBUF.md for a description of the API.

Closes #5300

1 files changed, 13 insertions, 32 deletions

diff --git a/lib/http.h b/lib/http.h
index 4c1825f60..cc262f7d3 100644
--- a/lib/http.h
+++ b/lib/http.h
@@ -44,38 +44,19 @@ char *Curl_copy_header_value(const char *header);
 
 char *Curl_checkProxyheaders(const struct connectdata *conn,
                              const char *thisheader);
-/* ------------------------------------------------------------------------- */
-/*
- * The add_buffer series of functions are used to build one large memory chunk
- * from repeated function invokes. Used so that the entire HTTP request can
- * be sent in one go.
- */
-struct Curl_send_buffer {
-  char *buffer;
-  size_t size_max;
-  size_t size_used;
-};
-typedef struct Curl_send_buffer Curl_send_buffer;
-
-Curl_send_buffer *Curl_add_buffer_init(void);
-void Curl_add_buffer_free(Curl_send_buffer **inp);
-CURLcode Curl_add_bufferf(Curl_send_buffer **inp, const char *fmt, ...)
-  WARN_UNUSED_RESULT;
-CURLcode Curl_add_buffer(Curl_send_buffer **inp, const void *inptr,
-                         size_t size) WARN_UNUSED_RESULT;
-CURLcode Curl_add_buffer_send(Curl_send_buffer **inp,
-                              struct connectdata *conn,
-                              curl_off_t *bytes_written,
-                              size_t included_body_bytes,
-                              int socketindex);
+CURLcode Curl_buffer_send(struct dynbuf *in,
+                          struct connectdata *conn,
+                          curl_off_t *bytes_written,
+                          size_t included_body_bytes,
+                          int socketindex);
 
 CURLcode Curl_add_timecondition(const struct connectdata *conn,
-                                Curl_send_buffer *buf);
+                                struct dynbuf *buf);
 CURLcode Curl_add_custom_headers(struct connectdata *conn,
                                  bool is_connect,
-                                 Curl_send_buffer *req_buffer);
+                                 struct dynbuf *req_buffer);
 CURLcode Curl_http_compile_trailers(struct curl_slist *trailers,
-                                    Curl_send_buffer **buffer,
+                                    struct dynbuf *buf,
                                     struct Curl_easy *handle);
 
 /* protocol-specific functions set up to be called by the main engine */
@@ -154,9 +135,9 @@ struct HTTP {
   } sending;
 
 #ifndef CURL_DISABLE_HTTP
-  Curl_send_buffer *send_buffer; /* used if the request couldn't be sent in
-                                    one chunk, points to an allocated
-                                    send_buffer struct */
+  struct dynbuf send_buffer; /* used if the request couldn't be sent in one
+                                chunk, points to an allocated send_buffer
+                                struct */
 #endif
 #ifdef USE_NGHTTP2
   /*********** for HTTP/2 we store stream-local data here *************/
@@ -164,10 +145,10 @@ struct HTTP {
 
   bool bodystarted;
   /* We store non-final and final response headers here, per-stream */
-  Curl_send_buffer *header_recvbuf;
+  struct dynbuf header_recvbuf;
   size_t nread_header_recvbuf; /* number of bytes in header_recvbuf fed into
                                   upper layer */
-  Curl_send_buffer *trailer_recvbuf;
+  struct dynbuf trailer_recvbuf;
   int status_code; /* HTTP status code */
   const uint8_t *pausedata; /* pointer to data received in on_data_chunk */
   size_t pauselen; /* the number of bytes left in data */