More robust member profile data retrieval

MemberEventContent: displayname and avatarUrl are now Omittables;
CS API doesn't guarantee their presence (see also
https://github.com/matrix-org/matrix-doc/issues/1375) but Quotient
used to assume they are always there, causing #412.
RoomMemberEvent: displayname() -> newDisplayName() and
avatarUrl() -> newAvatarUrl(), to emphasise the actual semantics (and
also the changed interface). The old signatures still work but are
deprecated.

Instead of roomMembername() (with weird camel-casing), three new
methods in addition to safeMemberName() are introduced to Room:
- memberName() - produces the "best known" display name for a
  given member; User::name() uses it to avoid the pitfall of #412.
- disambiguatedMemberName() - this is what roomMembername() used to be;
  not recommended for direct use when UI is concerned.
- safeMemberName() - remains as is, with the fix to the documentation
  that used to mislead that the function returns HTML-escaped content
  (it didn't, and doesn't).
- htmlSafeMemberName() - does what safeMemberName() claimed to do.

Respectively, memberNames() is deprecated in favor of safeMemberNames()
and htmlSafeMemberNames(). The corresponding Q_PROPERTY uses
safeMemberNames() now.

Similar to memberName(), Room has got memberAvatarUrl() to spare
User class from diving into Room state to find the member avatar URL.

Closes #412.

2 files changed, 31 insertions, 15 deletions

diff --git a/lib/events/roommemberevent.cpp b/lib/events/roommemberevent.cpp
index 35cbdb3a..f6b29f7f 100644
--- a/lib/events/roommemberevent.cpp
+++ b/lib/events/roommemberevent.cpp
@@ -50,10 +50,13 @@ using namespace Quotient;
 MemberEventContent::MemberEventContent(const QJsonObject& json)
     : membership(fromJson<MembershipType>(json["membership"_ls]))
     , isDirect(json["is_direct"_ls].toBool())
-    , displayName(sanitized(json["displayname"_ls].toString()))
-    , avatarUrl(json["avatar_url"_ls].toString())
+    , displayName(fromJson<Omittable<QString>>(json["displayname"_ls]))
+    , avatarUrl(fromJson<Omittable<QUrl>>(json["avatar_url"_ls]))
     , reason(json["reason"_ls].toString())
-{}
+{
+    if (displayName)
+        displayName = sanitized(*displayName);
+}
 
 void MemberEventContent::fillJson(QJsonObject* o) const
 {
@@ -62,9 +65,10 @@ void MemberEventContent::fillJson(QJsonObject* o) const
                "The key 'membership' must be explicit in MemberEventContent");
     if (membership != MembershipType::Undefined)
         o->insert(QStringLiteral("membership"), membershipStrings[membership]);
-    o->insert(QStringLiteral("displayname"), displayName);
-    if (avatarUrl.isValid())
-        o->insert(QStringLiteral("avatar_url"), avatarUrl.toString());
+    if (displayName)
+        o->insert(QStringLiteral("displayname"), *displayName);
+    if (avatarUrl && avatarUrl->isValid())
+        o->insert(QStringLiteral("avatar_url"), avatarUrl->toString());
     if (!reason.isEmpty())
         o->insert(QStringLiteral("reason"), reason);
 }
@@ -111,12 +115,16 @@ bool RoomMemberEvent::isUnban() const
 
 bool RoomMemberEvent::isRename() const
 {
-    auto prevName = prevContent() ? prevContent()->displayName : QString();
-    return displayName() != prevName;
+    auto prevName = prevContent() && prevContent()->displayName
+                        ? *prevContent()->displayName
+                        : QString();
+    return newDisplayName() != prevName;
 }
 
 bool RoomMemberEvent::isAvatarUpdate() const
 {
-    auto prevAvatarUrl = prevContent() ? prevContent()->avatarUrl : QUrl();
-    return avatarUrl() != prevAvatarUrl;
+    auto prevAvatarUrl = prevContent() && prevContent()->avatarUrl
+                             ? *prevContent()->avatarUrl
+                             : QUrl();
+    return newAvatarUrl() != prevAvatarUrl;
 }
diff --git a/lib/events/roommemberevent.h b/lib/events/roommemberevent.h
index 783b8207..35fd69a9 100644
--- a/lib/events/roommemberevent.h
+++ b/lib/events/roommemberevent.h
@@ -24,7 +24,7 @@
 namespace Quotient {
 class MemberEventContent : public EventContent::Base {
 public:
-    enum MembershipType : size_t {
+    enum MembershipType : unsigned char {
         Invite = 0,
         Join,
         Knock,
@@ -38,8 +38,8 @@ public:
 
     MembershipType membership;
     bool isDirect = false;
-    QString displayName;
-    QUrl avatarUrl;
+    Omittable<QString> displayName;
+    Omittable<QUrl> avatarUrl;
     QString reason;
 
 protected:
@@ -84,8 +84,16 @@ public:
     MembershipType membership() const { return content().membership; }
     QString userId() const { return fullJson()[StateKeyKeyL].toString(); }
     bool isDirect() const { return content().isDirect; }
-    QString displayName() const { return content().displayName; }
-    QUrl avatarUrl() const { return content().avatarUrl; }
+    Omittable<QString> newDisplayName() const { return content().displayName; }
+    Omittable<QUrl> newAvatarUrl() const { return content().avatarUrl; }
+    [[deprecated("Use newDisplayName() instead")]] QString displayName() const
+    {
+        return newDisplayName().value_or(QString());
+    }
+    [[deprecated("Use newAvatarUrl() instead")]] QUrl avatarUrl() const
+    {
+        return newAvatarUrl().value_or(QUrl());
+    }
     QString reason() const { return content().reason; }
     bool changesMembership() const;
     bool isBan() const;