Add quote API

Sticky encryption rule, requiring that all replies to encrypted messages
are encrypted, applies only to messages with a quote now.

Co-Authored-By: B. Petersen <r10s@b44t.com>

deltachat-ffi/deltachat.h

@@ -3675,6 +3675,63 @@ void            dc_msg_set_location           (dc_msg_t* msg, double latitude, d
 void            dc_msg_latefiling_mediasize   (dc_msg_t* msg, int width, int height, int duration);
 
 
+/**
+ * Set the message replying to.
+ * This allows optionally to reply to an explicit message
+ * instead of replying implicitly to the end of the chat.
+ *
+ * dc_msg_set_quote() copies some basic data from the quoted message object
+ * so that dc_msg_get_quoted_text() will always work.
+ * dc_msg_get_quoted_msg() gets back the quoted message only if it is _not_ deleted.
+ *
+ * @memberof dc_msg_t
+ * @param msg The message object to set the reply to.
+ * @param quote The quote to set for msg.
+ */
+void             dc_msg_set_quote             (dc_msg_t* msg, const dc_msg_t* quote);
+
+
+/**
+ * Get quoted text, if any.
+ * You can use this function also check if there is a quote for a message.
+ *
+ * The text is a summary of the original text,
+ * similar to what is shown in the chatlist.
+ *
+ * If available, you can get the whole quoted message object using dc_msg_get_quoted_msg().
+ *
+ * @memberof dc_msg_t
+ * @param msg The message object.
+ * @return The quoted text or NULL if there is no quote.
+ *     Returned strings must be released using dc_str_unref().
+ */
+char*           dc_msg_get_quoted_text        (const dc_msg_t* msg);
+
+
+/**
+ * Get quoted message, if available.
+ * UIs might use this information to offer "jumping back" to the quoted message
+ * or to enrich displaying the quote.
+ *
+ * If this function returns NULL,
+ * this does not mean there is no quote for the message -
+ * it might also mean that a quote exist but the quoted message is deleted meanwhile.
+ * Therefore, do not use this function to check if there is a quote for a message.
+ * To check if a message has a quote, use dc_msg_get_quoted_text().
+ *
+ * To display the quote in the chat, use dc_msg_get_quoted_text() as a primary source,
+ * however, one might add information from the message object (eg. an image).
+ *
+ * It is not guaranteed that the message belong to the same chat.
+ *
+ * @memberof dc_msg_t
+ * @param msg The message object.
+ * @return The quoted message or NULL.
+ *     Must be freed using dc_msg_unref() after usage.
+ */
+dc_msg_t*       dc_msg_get_quoted_msg         (const dc_msg_t* msg);
+
+
 /**
  * @class dc_contact_t
  *

deltachat-ffi/src/lib.rs

@@ -2975,6 +2975,58 @@ pub unsafe extern "C" fn dc_msg_get_error(msg: *mut dc_msg_t) -> *mut libc::c_ch
     }
 }
 
+#[no_mangle]
+pub unsafe extern "C" fn dc_msg_set_quote(msg: *mut dc_msg_t, quote: *const dc_msg_t) {
+    if msg.is_null() {
+        eprintln!("ignoring careless call to dc_msg_set_quote()");
+        return;
+    }
+    let ffi_msg = &mut *msg;
+    let ffi_quote = &*quote;
+
+    ffi_msg
+        .message
+        .set_quote(&ffi_quote.message)
+        .log_err(&*ffi_msg.context, "failed to set quote")
+        .ok();
+}
+
+#[no_mangle]
+pub unsafe extern "C" fn dc_msg_get_quoted_text(msg: *const dc_msg_t) -> *mut libc::c_char {
+    if msg.is_null() {
+        eprintln!("ignoring careless call to dc_msg_get_quoted_text()");
+        return ptr::null_mut();
+    }
+    let ffi_msg: &MessageWrapper = &*msg;
+    ffi_msg
+        .message
+        .quoted_text()
+        .map_or_else(ptr::null_mut, |s| s.strdup())
+}
+
+#[no_mangle]
+pub unsafe extern "C" fn dc_msg_get_quoted_msg(msg: *const dc_msg_t) -> *mut dc_msg_t {
+    if msg.is_null() {
+        eprintln!("ignoring careless call to dc_get_quoted_msg()");
+        return ptr::null_mut();
+    }
+    let ffi_msg: &MessageWrapper = &*msg;
+    let context = &*ffi_msg.context;
+    let res = block_on(async move {
+        ffi_msg
+            .message
+            .quoted_message(context)
+            .await
+            .log_err(context, "failed to get quoted message")
+            .unwrap_or(None)
+    });
+
+    match res {
+        Some(message) => Box::into_raw(Box::new(MessageWrapper { context, message })),
+        None => ptr::null_mut(),
+    }
+}
+
 // dc_contact_t
 
 /// FFI struct for [dc_contact_t]