truncate long texts and make the whole text accessible via has_html()/get_html()

src/constants.rs

@@ -165,8 +165,16 @@ pub const DC_MSG_ID_MARKER1: u32 = 1;
 pub const DC_MSG_ID_DAYMARKER: u32 = 9;
 pub const DC_MSG_ID_LAST_SPECIAL: u32 = 9;
 
+/// string that indicates sth. is left out or truncated
+pub const DC_ELLIPSE: &str = "[...]";
+
+/// to keep bubbles and chat flow usable, we limit the text length to DC_DESIRED_TEXT_LEN.
+/// if the text is longer, the full text can be retrieved usind has_html()/get_html().
+pub const DC_DESIRED_TEXT_LEN: usize = 20000;
+
 /// approx. max. length returned by dc_msg_get_text()
 pub const DC_MAX_GET_TEXT_LEN: usize = 30000;
+
 /// approx. max. length returned by dc_get_msg_info()
 pub const DC_MAX_GET_INFO_LEN: usize = 100_000;
 

src/dc_tools.rs

@@ -17,7 +17,7 @@ use chrono::{Local, TimeZone};
 use rand::{thread_rng, Rng};
 
 use crate::chat::{add_device_msg, add_device_msg_with_importance};
-use crate::constants::{Viewtype, DC_OUTDATED_WARNING_DAYS};
+use crate::constants::{Viewtype, DC_ELLIPSE, DC_OUTDATED_WARNING_DAYS};
 use crate::context::Context;
 use crate::events::EventType;
 use crate::message::Message;
@@ -28,10 +28,8 @@ use crate::stock_str;
 /// end of the shortened string.
 #[allow(clippy::indexing_slicing)]
 pub(crate) fn dc_truncate(buf: &str, approx_chars: usize) -> Cow<str> {
-    let ellipse = "[...]";
-
     let count = buf.chars().count();
-    if approx_chars > 0 && count > approx_chars + ellipse.len() {
+    if approx_chars > 0 && count > approx_chars + DC_ELLIPSE.len() {
         let end_pos = buf
             .char_indices()
             .nth(approx_chars)
@@ -39,9 +37,9 @@ pub(crate) fn dc_truncate(buf: &str, approx_chars: usize) -> Cow<str> {
             .unwrap_or_default();
 
         if let Some(index) = buf[..end_pos].rfind(|c| c == ' ' || c == '\n') {
-            Cow::Owned(format!("{}{}", &buf[..=index], ellipse))
+            Cow::Owned(format!("{}{}", &buf[..=index], DC_ELLIPSE))
         } else {
-            Cow::Owned(format!("{}{}", &buf[..end_pos], ellipse))
+            Cow::Owned(format!("{}{}", &buf[..end_pos], DC_ELLIPSE))
         }
     } else {
         Cow::Borrowed(buf)

src/mimeparser.rs

@@ -12,10 +12,10 @@ use percent_encoding::percent_decode_str;
 
 use crate::aheader::Aheader;
 use crate::blob::BlobObject;
-use crate::constants::Viewtype;
+use crate::constants::{Viewtype, DC_DESIRED_TEXT_LEN, DC_ELLIPSE};
 use crate::contact::addr_normalize;
 use crate::context::Context;
-use crate::dc_tools::dc_get_filemeta;
+use crate::dc_tools::{dc_get_filemeta, dc_truncate};
 use crate::dehtml::dehtml;
 use crate::e2ee;
 use crate::events::EventType;
@@ -817,6 +817,14 @@ impl MimeMessage {
                             (simplified_txt, top_quote)
                         };
 
+                        let simplified_txt =
+                            if simplified_txt.len() > DC_DESIRED_TEXT_LEN + DC_ELLIPSE.len() {
+                                self.is_mime_modified = true;
+                                dc_truncate(&*simplified_txt, DC_DESIRED_TEXT_LEN).to_string()
+                            } else {
+                                simplified_txt
+                            };
+
                         if !simplified_txt.is_empty() || simplified_quote.is_some() {
                             let mut part = Part {
                                 dehtml_failed,
@@ -2781,6 +2789,7 @@ On 2020-10-25, Bob wrote:
         static REPEAT_TXT: &str = "this text with 42 chars is just repeated.\n";
         static REPEAT_CNT: usize = 2000; // results in a text of 84k, should be more than DC_MAX_GET_TEXT_LEN
         let long_txt = format!("From: alice@c.de\n\n{}", REPEAT_TXT.repeat(REPEAT_CNT));
+        assert!(DC_DESIRED_TEXT_LEN + DC_ELLIPSE.len() < DC_MAX_GET_TEXT_LEN);
 
         let mimemsg = MimeMessage::from_bytes(&t, long_txt.as_ref())
             .await