cli tool: do not use mime.h private structures.

Option -F generates an intermediate representation of the mime structure
that is used later to create the libcurl mime structure and generate
the --libcurl statements.

Reported-by: Daniel Stenberg
Fixes #3532
Closes #3546

src/tool_formparse.h

@@ -7,7 +7,7 @@
  *                            | (__| |_| |  _ <| |___
  *                             \___|\___/|_| \_\_____|
  *
- * Copyright (C) 1998 - 2017, Daniel Stenberg, <daniel@haxx.se>, et al.
+ * Copyright (C) 1998 - 2019, Daniel Stenberg, <daniel@haxx.se>, et al.
  *
  * This software is licensed as described in the file COPYING, which
  * you should have received as part of this distribution. The terms
@@ -23,10 +23,50 @@
  ***************************************************************************/
 #include "tool_setup.h"
 
+/* Private structure for mime/parts. */
+
+typedef enum {
+  TOOLMIME_NONE = 0,
+  TOOLMIME_PARTS,
+  TOOLMIME_DATA,
+  TOOLMIME_FILE,
+  TOOLMIME_FILEDATA,
+  TOOLMIME_STDIN,
+  TOOLMIME_STDINDATA
+} toolmimekind;
+
+typedef struct tool_mime        tool_mime;
+struct tool_mime {
+  /* Structural fields. */
+  toolmimekind kind;            /* Part kind. */
+  tool_mime *parent;            /* Parent item. */
+  tool_mime *prev;              /* Previous sibling (reverse order link). */
+  /* Common fields. */
+  const char *data;             /* Actual data or data filename. */
+  const char *name;             /* Part name. */
+  const char *filename;         /* Part's filename. */
+  const char *type;             /* Part's mime type. */
+  const char *encoder;          /* Part's requested encoding. */
+  struct curl_slist *headers;   /* User-defined headers. */
+  /* TOOLMIME_PARTS fields. */
+  tool_mime *subparts;          /* Part's subparts. */
+  curl_mime *handle;            /* Libcurl mime handle. */
+  /* TOOLMIME_STDIN/TOOLMIME_STDINDATA fields. */
+  curl_off_t origin;            /* Stdin read origin offset. */
+  curl_off_t size;              /* Stdin data size. */
+  curl_off_t curpos;            /* Stdin current read position. */
+  struct GlobalConfig *config;  /* For access from callback. */
+};
+
+size_t tool_mime_stdin_read(char *buffer,
+                            size_t size, size_t nitems, void *arg);
+int tool_mime_stdin_seek(void *instream, curl_off_t offset, int whence);
+
 int formparse(struct OperationConfig *config,
               const char *input,
-              curl_mime **mimepost,
-              curl_mime **mimecurrent,
+              tool_mime **mimepost,
+              tool_mime **mimecurrent,
               bool literal_value);
+void tool_mime_free(tool_mime *mime);
 
 #endif /* HEADER_CURL_TOOL_FORMPARSE_H */