From 5814135512ffb612ac874fad0b089fdda3338236 Mon Sep 17 00:00:00 2001
From: Tyrolyean <tyrolyean@tyrolyean.net>
Date: Wed, 29 Apr 2020 16:29:36 +0200
Subject: [PATCH] Added change of header propagation

Signed-off-by: Tyrolyean <tyrolyean@tyrolyean.net>
---
 include/mail.h |  6 ++++++
 src/attach.c   |  3 +++
 src/mail.c     | 46 ++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 55 insertions(+)

diff --git a/include/mail.h b/include/mail.h
index 62e290f..ac7a1ce 100644
--- a/include/mail.h
+++ b/include/mail.h
@@ -21,6 +21,7 @@
 #include <stdint.h>
 #include <stddef.h>
 #include <stdbool.h>
+#include <sys/types.h>
 
 struct email_t{
 	char* message;
@@ -56,6 +57,11 @@ struct email_t{
 int append_header(struct email_t* mail, const char* key, const char* value);
 int append_to_header(struct email_t* mail, const char* pair);
 
+struct email_t* get_root_mail(struct email_t* mail);
+
+void propagate_insert_delete(struct email_t* mail, char* change_p,  
+	ssize_t change);
+
 #define MULTIPART_MIME "multipart/"
 
 #endif /* MAIL_H */
diff --git a/src/attach.c b/src/attach.c
index a3d96e6..a04b36c 100644
--- a/src/attach.c
+++ b/src/attach.c
@@ -64,10 +64,12 @@ struct email_t* mail_from_text(char* message, size_t length,
 		if(mime_type != NULL){
 			mail->ct_len = value_length;
 			mail->content_type = mime_type;
+
 			if(verbose){
 				printf("Found content type: %.*s\n",
 					(int)value_length, mime_type);
 			}
+			
 			if(strncasecmp(mime_type, MULTIPART_MIME, 
 				strlen(MULTIPART_MIME)) == 0){
 				/* We have multiple messages cramped inside this
@@ -88,6 +90,7 @@ struct email_t* mail_from_text(char* message, size_t length,
 							(int)bd_len, bd);
 					}
 				}
+				/* Expands the mail message to multiple ones */
 				unravel_multipart_mail(mail);
 
 			}
diff --git a/src/mail.c b/src/mail.c
index e34cd01..f711cf7 100644
--- a/src/mail.c
+++ b/src/mail.c
@@ -67,9 +67,15 @@ int append_to_header(struct email_t* mail, const char* pair){
 	buffer[0] = '\r';
 	buffer[1] = '\n';
 	strcat(buffer, pair);
+	struct email_t* root = get_root_mail(mail);
+	size_t root_offset = mail->header_len + (mail->message - root->message);
 
 	mail->message=insert_string(mail->message, buffer, mail->message_length, 
 		mail->header_len);
+	
+	propagate_insert_delete(root, root->message+root_offset, 
+		strlen(buffer));
+	
 	free(buffer);
 	redetect_body_head(mail);
 
@@ -77,3 +83,43 @@ int append_to_header(struct email_t* mail, const char* pair){
 
 }
 
+struct email_t* get_root_mail(struct email_t* mail){
+	
+	if(mail == NULL){
+		return NULL;
+	}
+	
+	if(mail->parent == NULL){
+		return mail;
+	}else{
+		return get_root_mail(mail->parent);
+	}
+
+}
+
+/* This propagates a size change inside the root email down to all submails
+ * Call this function with the root, changes will propagate down via recursion!
+ * The change pointer should point to the last character IN FRONT of the change.
+ * an insert has a positive amount of chane, a delete a negative one.
+ */
+void propagate_insert_delete(struct email_t* mail, char* change_p,
+	ssize_t change){
+	
+	if(mail == NULL || change_p == NULL || change == 0){
+		/* MISSION ABORT!! */
+		return;
+	}
+
+	if(mail->message >= change_p){
+		mail->message += change;
+	}
+
+	if(mail->is_multipart){
+		for(size_t i = 0; i < mail->submes_cnt; i++){
+			propagate_insert_delete(mail->submes[i], change_p, 
+				change);
+		}
+	}
+	
+	return;
+}