From 48ffee5fa78f44bd00d76772ad79ae4eeb6c8dc4 Mon Sep 17 00:00:00 2001
From: Alexey Andreyev <aa13q@ya.ru>
Date: Wed, 15 May 2019 16:36:02 +0300
Subject: Move out the logic of the hue calculation to utils

---
 lib/user.cpp | 20 +-------------------
 lib/util.cpp | 19 +++++++++++++++++++
 lib/util.h   |  8 ++++++++
 3 files changed, 28 insertions(+), 19 deletions(-)

diff --git a/lib/user.cpp b/lib/user.cpp
index 7f3f11f6..7b695618 100644
--- a/lib/user.cpp
+++ b/lib/user.cpp
@@ -33,9 +33,6 @@
 #include <QtCore/QStringBuilder>
 #include <QtCore/QElapsedTimer>
 
-#include <QtCore/QCryptographicHash>
-#include <QtCore/QtEndian>
-
 #include <functional>
 
 using namespace QMatrixClient;
@@ -50,23 +47,8 @@ class User::Private
             return Avatar(move(url));
         }
 
-        qreal makeHueF()
-        {
-            Q_ASSERT(!userId.isEmpty());
-            QByteArray hash = QCryptographicHash::hash(userId.toUtf8(),
-                                                       QCryptographicHash::Sha1);
-            QDataStream dataStream(qToLittleEndian(hash).left(2));
-            dataStream.setByteOrder(QDataStream::LittleEndian);
-            quint16 hashValue;
-            dataStream >> hashValue;
-            const auto hueF =
-                    qreal(hashValue)/std::numeric_limits<quint16>::max();
-            Q_ASSERT((0 <= hueF) && (hueF <= 1));
-            return hueF;
-        }
-
         Private(QString userId, Connection* connection)
-            : userId(move(userId)), connection(connection), hueF(makeHueF())
+            : userId(move(userId)), connection(connection), hueF(stringToHueF(this->userId))
         { }
 
         QString userId;
diff --git a/lib/util.cpp b/lib/util.cpp
index 4e17d2f9..01d4e77b 100644
--- a/lib/util.cpp
+++ b/lib/util.cpp
@@ -23,6 +23,10 @@
 #include <QtCore/QDir>
 #include <QtCore/QStringBuilder>
 
+#include <QtCore/QCryptographicHash>
+#include <QtCore/QtEndian>
+#include <QtCore/QDataStream>
+
 static const auto RegExpOptions =
     QRegularExpression::CaseInsensitiveOption
     | QRegularExpression::OptimizeOnFirstUsageOption
@@ -93,6 +97,21 @@ QString QMatrixClient::cacheLocation(const QString& dirName)
     return cachePath;
 }
 
+qreal QMatrixClient::stringToHueF(const QString &string)
+{
+    Q_ASSERT(!string.isEmpty());
+    QByteArray hash = QCryptographicHash::hash(string.toUtf8(),
+                                               QCryptographicHash::Sha1);
+    QDataStream dataStream(qToLittleEndian(hash).left(2));
+    dataStream.setByteOrder(QDataStream::LittleEndian);
+    quint16 hashValue;
+    dataStream >> hashValue;
+    const auto hueF =
+            qreal(hashValue)/std::numeric_limits<quint16>::max();
+    Q_ASSERT((0 <= hueF) && (hueF <= 1));
+    return hueF;
+}
+
 // Tests for function_traits<>
 
 #ifdef Q_CC_CLANG
diff --git a/lib/util.h b/lib/util.h
index f08c1c95..eda817a1 100644
--- a/lib/util.h
+++ b/lib/util.h
@@ -314,5 +314,13 @@ namespace QMatrixClient
      * \param dir path to cache directory relative to the standard cache path
      */
     QString cacheLocation(const QString& dirName);
+
+    /** Hue color component of based of the hash of the string.
+     * The implementation is based on XEP-0392:
+     * https://xmpp.org/extensions/xep-0392.html
+     * Naming and range are the same as QColor's hueF method:
+     * https://doc.qt.io/qt-5/qcolor.html#integer-vs-floating-point-precision
+     */
+    qreal stringToHueF(const QString& string);
 }  // namespace QMatrixClient
 
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