QTextureFileData: support key value metadata

Task-Id: QTBUG-76970
Pick-to: 6.1
Change-Id: I9dba1b373250cea4d0c806997290a7afcdc900d7
Reviewed-by: Eirik Aavitsland <eirik.aavitsland@qt.io>

4 files changed, 56 insertions, 3 deletions

diff --git a/src/gui/util/qktxhandler.cpp b/src/gui/util/qktxhandler.cpp
index 27fb69a348..cd8ca3635e 100644
--- a/src/gui/util/qktxhandler.cpp
+++ b/src/gui/util/qktxhandler.cpp
@@ -146,7 +146,12 @@ QTextureFileData QKtxHandler::read()
 
     texData.setNumLevels(decode(header->numberOfMipmapLevels));
     texData.setNumFaces(decode(header->numberOfFaces));
-    quint32 offset = headerSize + decode(header->bytesOfKeyValueData);
+
+    const quint32 bytesOfKeyValueData = decode(header->bytesOfKeyValueData);
+    if (headerSize + bytesOfKeyValueData < buf.length()) // oob check
+        texData.setKeyValueMetadata(
+                decodeKeyValues(QByteArrayView(buf.data() + headerSize, bytesOfKeyValueData)));
+    quint32 offset = headerSize + bytesOfKeyValueData;
 
     constexpr int MAX_ITERATIONS = 32; // cap iterations in case of corrupt data
 
@@ -213,7 +218,39 @@ bool QKtxHandler::checkHeader(const KTXHeader &header)
     return is2D && (isCubeMap || isCompressedImage);
 }
 
-quint32 QKtxHandler::decode(quint32 val)
+QMap<QByteArray, QByteArray> QKtxHandler::decodeKeyValues(QByteArrayView view) const
+{
+    QMap<QByteArray, QByteArray> output;
+    quint32 offset = 0;
+    while (offset < view.size() + sizeof(quint32)) {
+        const quint32 keyAndValueByteSize =
+                decode(qFromUnaligned<quint32>(view.constData() + offset));
+        offset += sizeof(quint32);
+
+        if (offset + keyAndValueByteSize > view.size())
+            break; // oob read
+
+        // 'key' is a UTF-8 string ending with a null terminator, 'value' is the rest.
+        // To separate the key and value we convert the complete data to utf-8 and find the first
+        // null terminator from the left, here we split the data into two.
+        const auto str = QString::fromUtf8(view.constData() + offset, keyAndValueByteSize);
+        const int idx = str.indexOf(QLatin1Char('\0'));
+        if (idx == -1)
+            continue;
+
+        const QByteArray key = str.left(idx).toUtf8();
+        const size_t keySize = key.size() + 1; // Actual data size
+        const QByteArray value = QByteArray::fromRawData(view.constData() + offset + keySize,
+                                                         keyAndValueByteSize - keySize);
+
+        offset = withPadding(offset + keyAndValueByteSize, 4);
+        output.insert(key, value);
+    }
+
+    return output;
+}
+
+quint32 QKtxHandler::decode(quint32 val) const
 {
     return inverseEndian ? qbswap<quint32>(val) : val;
 }
diff --git a/src/gui/util/qktxhandler_p.h b/src/gui/util/qktxhandler_p.h
index 19f7b0e79a..4298433f36 100644
--- a/src/gui/util/qktxhandler_p.h
+++ b/src/gui/util/qktxhandler_p.h
@@ -68,7 +68,8 @@ public:
 
 private:
     bool checkHeader(const KTXHeader &header);
-    quint32 decode(quint32 val);
+    QMap<QByteArray, QByteArray> decodeKeyValues(QByteArrayView view) const;
+    quint32 decode(quint32 val) const;
 
     bool inverseEndian = false;
 };
diff --git a/src/gui/util/qtexturefiledata.cpp b/src/gui/util/qtexturefiledata.cpp
index 0a3958aaf2..6549206a26 100644
--- a/src/gui/util/qtexturefiledata.cpp
+++ b/src/gui/util/qtexturefiledata.cpp
@@ -100,6 +100,7 @@ public:
     quint32 baseInternalFormat = 0;
     int numFaces = 0;
     int numLevels = 0;
+    QMap<QByteArray, QByteArray> keyValues;
 };
 
 QTextureFileData::QTextureFileData()
@@ -292,6 +293,17 @@ void QTextureFileData::setLogName(const QByteArray &name)
         d->logName = name;
 }
 
+QMap<QByteArray, QByteArray> QTextureFileData::keyValueMetadata() const
+{
+    return d ? d->keyValues : QMap<QByteArray, QByteArray>();
+}
+
+void QTextureFileData::setKeyValueMetadata(const QMap<QByteArray, QByteArray> &keyValues)
+{
+    if (d)
+        d->keyValues = keyValues;
+}
+
 static QByteArray glFormatName(quint32 fmt)
 {
     return QByteArray("0x" + QByteArray::number(fmt, 16).rightJustified(4, '0'));
diff --git a/src/gui/util/qtexturefiledata_p.h b/src/gui/util/qtexturefiledata_p.h
index f6a03c0550..e553733d69 100644
--- a/src/gui/util/qtexturefiledata_p.h
+++ b/src/gui/util/qtexturefiledata_p.h
@@ -107,6 +107,9 @@ public:
     QByteArray logName() const;
     void setLogName(const QByteArray &name);
 
+    QMap<QByteArray, QByteArray> keyValueMetadata() const;
+    void setKeyValueMetadata(const QMap<QByteArray, QByteArray> &keyValues);
+
 private:
     QSharedDataPointer<QTextureFileDataPrivate> d;
 };