mime: relax easy/mime structures binding

Deprecation and removal of codeset conversion support from the library
have released the strict need for an early binding of mime structures to
an easy handle (https://github.com/curl/curl/commit/2610142).

This constraint currently forces to create the handle before the mime
structure and the latter cannot be attached to another handle once
created (see https://curl.se/mail/lib-2022-08/0027.html).

This commit removes the handle pointers from the mime structures
allowing more flexibility on their use.

When an easy handle is duplicated, bound mime structures must however
still be duplicated too as their components hold send-time dynamic
information.

Closes #9927

1 files changed, 2 insertions, 2 deletions

diff --git a/lib/easy.c b/lib/easy.c
index b61ea7b7c..d7f93be1e 100644
--- a/lib/easy.c
+++ b/lib/easy.c
@@ -828,7 +828,7 @@ static CURLcode dupset(struct Curl_easy *dst, struct Curl_easy *src)
   /* Copy src->set into dst->set first, then deal with the strings
      afterwards */
   dst->set = src->set;
-  Curl_mime_initpart(&dst->set.mimepost, dst);
+  Curl_mime_initpart(&dst->set.mimepost);
 
   /* clear all string pointers first */
   memset(dst->set.str, 0, STRING_LAST * sizeof(char *));
@@ -862,7 +862,7 @@ static CURLcode dupset(struct Curl_easy *dst, struct Curl_easy *src)
   }
 
   /* Duplicate mime data. */
-  result = Curl_mime_duppart(&dst->set.mimepost, &src->set.mimepost);
+  result = Curl_mime_duppart(dst, &dst->set.mimepost, &src->set.mimepost);
 
   if(src->set.resolve)
     dst->state.resolve = dst->set.resolve;