+/* mime-node.c */
+
+/* mime_node_t represents a single node in a MIME tree. A MIME tree
+ * abstracts the different ways of traversing different types of MIME
+ * parts, allowing a MIME message to be viewed as a generic tree of
+ * parts. Message-type parts have one child, multipart-type parts
+ * have multiple children, and leaf parts have zero children.
+ */
+typedef struct mime_node {
+ /* The MIME object of this part. This will be a GMimeMessage,
+ * GMimePart, GMimeMultipart, or a subclass of one of these.
+ *
+ * This will never be a GMimeMessagePart because GMimeMessagePart
+ * is structurally redundant with GMimeMessage. If this part is a
+ * message (that is, 'part' is a GMimeMessage), then either
+ * envelope_file will be set to a notmuch_message_t (for top-level
+ * messages) or envelope_part will be set to a GMimeMessagePart
+ * (for embedded message parts).
+ */
+ GMimeObject *part;
+
+ /* If part is a GMimeMessage, these record the envelope of the
+ * message: either a notmuch_message_t representing a top-level
+ * message, or a GMimeMessagePart representing a MIME part
+ * containing a message.
+ */
+ notmuch_message_t *envelope_file;
+ GMimeMessagePart *envelope_part;
+
+ /* The number of children of this part. */
+ int nchildren;
+
+ /* The parent of this node or NULL if this is the root node. */
+ struct mime_node *parent;
+
+ /* The depth-first part number of this child if the MIME tree is
+ * being traversed in depth-first order, or -1 otherwise. */
+ int part_num;
+
+ /* True if decryption of this part was attempted. */
+ notmuch_bool_t decrypt_attempted;
+ /* True if decryption of this part's child succeeded. In this
+ * case, the decrypted part is substituted for the second child of
+ * this part (which would usually be the encrypted data). */
+ notmuch_bool_t decrypt_success;
+
+ /* True if signature verification on this part was attempted. */
+ notmuch_bool_t verify_attempted;
+#ifdef GMIME_ATLEAST_26
+ /* The list of signatures for signed or encrypted containers. If
+ * there are no signatures, this will be NULL. */
+ GMimeSignatureList* sig_list;
+#else
+ /* For signed or encrypted containers, the validity of the
+ * signature. May be NULL if signature verification failed. If
+ * there are simply no signatures, this will be non-NULL with an
+ * empty signers list. */
+ const GMimeSignatureValidity *sig_validity;
+#endif
+
+ /* Internal: Context inherited from the root iterator. */
+ struct mime_node_context *ctx;
+
+ /* Internal: For successfully decrypted multipart parts, the
+ * decrypted part to substitute for the second child. */
+ GMimeObject *decrypted_child;
+
+ /* Internal: The next child for depth-first traversal and the part
+ * number to assign it (or -1 if unknown). */
+ int next_child;
+ int next_part_num;
+} mime_node_t;
+
+/* Construct a new MIME node pointing to the root message part of
+ * message. If cryptoctx is non-NULL, it will be used to verify
+ * signatures on any child parts. If decrypt is true, then cryptoctx
+ * will additionally be used to decrypt any encrypted child parts.
+ *
+ * Return value:
+ *
+ * NOTMUCH_STATUS_SUCCESS: Root node is returned in *node_out.
+ *
+ * NOTMUCH_STATUS_FILE_ERROR: Failed to open message file.
+ *
+ * NOTMUCH_STATUS_OUT_OF_MEMORY: Out of memory.
+ */
+notmuch_status_t
+mime_node_open (const void *ctx, notmuch_message_t *message,
+#ifdef GMIME_ATLEAST_26
+ GMimeCryptoContext *cryptoctx,
+#else
+ GMimeCipherContext *cryptoctx,
+#endif
+ notmuch_bool_t decrypt, mime_node_t **node_out);
+
+/* Return a new MIME node for the requested child part of parent.
+ * parent will be used as the talloc context for the returned child
+ * node.
+ *
+ * In case of any failure, this function returns NULL, (after printing
+ * an error message on stderr).
+ */
+mime_node_t *
+mime_node_child (mime_node_t *parent, int child);
+
+/* Return the nth child of node in a depth-first traversal. If n is
+ * 0, returns node itself. Returns NULL if there is no such part. */
+mime_node_t *
+mime_node_seek_dfs (mime_node_t *node, int n);
+
+#include "command-line-arguments.h"