headers: make curl_easy_header and nextheader return different buffers

By letting curl_easy_header() and curl_easy_nextheader() store the
header data in their own struct storage when they return a pointer to
it, it makes it possible for applications to use them both in a loop.
Like the curl tool does.

Reported-by: Boris Okunskiy
Fixes #10704
Closes #10707

diff --git a/lib/headers.c b/lib/headers.c
index 22e0e01258d3daf79a6ebcc9a4bdb77d3a33d7bd..6cd7e317032f8c2fc50198ba225ef21f4739019c 100644 (file)
--- a/lib/headers.c
+++ b/lib/headers.c
@@ -38,14 +38,13 @@
 
 /* Generate the curl_header struct for the user. This function MUST assign all
    struct fields in the output struct. */
-static void copy_header_external(struct Curl_easy *data,
-                                 struct Curl_header_store *hs,
+static void copy_header_external(struct Curl_header_store *hs,
                                  size_t index,
                                  size_t amount,
                                  struct Curl_llist_element *e,
-                                 struct curl_header **hout)
+                                 struct curl_header *hout)
 {
-  struct curl_header *h = *hout = &data->state.headerout;
+  struct curl_header *h = hout;
   h->name = hs->name;
   h->value = hs->value;
   h->amount = amount;
@@ -118,7 +117,9 @@ CURLHcode curl_easy_header(CURL *easy,
       return CURLHE_MISSING;
   }
   /* this is the name we want */
-  copy_header_external(data, hs, nameindex, amount, e_pick, hout);
+  copy_header_external(hs, nameindex, amount, e_pick,
+                       &data->state.headerout[0]);
+  *hout = &data->state.headerout[0];
   return CURLHE_OK;
 }
 
@@ -132,7 +133,6 @@ struct curl_header *curl_easy_nextheader(CURL *easy,
   struct Curl_llist_element *pick;
   struct Curl_llist_element *e;
   struct Curl_header_store *hs;
-  struct curl_header *hout;
   size_t amount = 0;
   size_t index = 0;
 
@@ -179,8 +179,9 @@ struct curl_header *curl_easy_nextheader(CURL *easy,
       index = amount - 1;
   }
 
-  copy_header_external(data, hs, index, amount, pick, &hout);
-  return hout;
+  copy_header_external(hs, index, amount, pick,
+                       &data->state.headerout[1]);
+  return &data->state.headerout[1];
 }
 
 static CURLcode namevalue(char *header, size_t hlen, unsigned int type,

diff --git a/lib/urldata.h b/lib/urldata.h
index 75dca5e7475143baeb7b7e3b29f45d326894428b..bf5daaf5067dc9b3e74b688ff2a70436b680a1a1 100644 (file)
--- a/lib/urldata.h
+++ b/lib/urldata.h
@@ -1378,7 +1378,7 @@ struct UrlState {
   struct dynbuf trailers_buf; /* a buffer containing the compiled trailing
                                  headers */
   struct Curl_llist httphdrs; /* received headers */
-  struct curl_header headerout; /* for external purposes */
+  struct curl_header headerout[2]; /* for external purposes */
   struct Curl_header_store *prevhead; /* the latest added header */
   trailers_state trailers_state; /* whether we are sending trailers
                                     and what stage are we at */