From 27f9fdedfff51c4a0664fd36ed52624b43d88430 Mon Sep 17 00:00:00 2001
From: Damien Caliste <dcaliste@free.fr>
Date: Wed, 18 Jun 2025 11:43:13 +0200
Subject: Setup references header when replying to a message

Add a convenient function in QMailMessage to
properly compute the In-Reply-to: and References:
headers when replying to a message.

Change-Id: Ibe962383d95e101b612258eb0ced980fef7e7203
Reviewed-by: Pekka Vuorela <pvuorela@iki.fi>
---
 src/libraries/qmfclient/qmailmessage.cpp | 28 ++++++++++++++++++++++++++++
 src/libraries/qmfclient/qmailmessage.h   |  2 ++
 2 files changed, 30 insertions(+)

(limited to 'src')

diff --git a/src/libraries/qmfclient/qmailmessage.cpp b/src/libraries/qmfclient/qmailmessage.cpp
index cb900418..70fb5c66 100644
--- a/src/libraries/qmfclient/qmailmessage.cpp
+++ b/src/libraries/qmfclient/qmailmessage.cpp
@@ -8563,6 +8563,34 @@ void QMailMessage::setInReplyTo(const QString &messageId)
     partContainerImpl()->setInReplyTo(messageId);
 }
 
+/*!
+    Setup In-Reply-To: and References: header fields according to RFC2822
+    section 3.6.4. Also internally set the metadata inResponseTo to point
+    to the id() of \a msg, if valid.
+ */
+void QMailMessage::setInResponseTo(const QMailMessage &msg)
+{
+    if (msg.id().isValid()) {
+        setInResponseTo(msg.id());
+    }
+    QString references(msg.headerFieldText(QLatin1String("References")));
+    if (references.isEmpty()) {
+        references = msg.inReplyTo();
+    }
+    const QString precursorId(msg.headerFieldText(QLatin1String("Message-ID")));
+    if (!precursorId.isEmpty()) {
+        setInReplyTo(precursorId);
+
+        if (!references.isEmpty()) {
+            references.append(' ');
+        }
+        references.append(precursorId);
+    }
+    if (!references.isEmpty()) {
+        setHeaderField(QLatin1String("References"), references);
+    }
+}
+
 /*!
     Returns a list of all the recipients specified for the message, either as To, CC, or BCC addresses.
 
diff --git a/src/libraries/qmfclient/qmailmessage.h b/src/libraries/qmfclient/qmailmessage.h
index 2e3c211f..86525fad 100644
--- a/src/libraries/qmfclient/qmailmessage.h
+++ b/src/libraries/qmfclient/qmailmessage.h
@@ -786,6 +786,8 @@ public:
     virtual QString inReplyTo() const;
     virtual void setInReplyTo(const QString &s);
 
+    void setInResponseTo(const QMailMessage &msg);
+
     virtual uint contentSize() const;
     virtual void setContentSize(uint size);
 
-- 
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