From fab0ed9a65a451d9a7a3b7ac617a0abc3176049a Mon Sep 17 00:00:00 2001
From: Nicolas Fella <nicolas.fella@kdab.com>
Date: Sat, 19 Sep 2020 16:56:21 +0200
Subject: Allow loading SVG files with a doctype declaration

SVGs may have a DOCTYPE declaration
(https://www.w3.org/TR/2003/REC-SVGMobile-20030114/)
in their first line.

This patch makes sure those SVGs are loaded properly

Fixes: QTBUG-87583
Change-Id: Ia3dcb519b6ee2b498dc81ef496764d99ea6c4a9a
Reviewed-by: Eirik Aavitsland <eirik.aavitsland@qt.io>
Reviewed-by: Robert Loehning <robert.loehning@qt.io>
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>
(cherry picked from commit 2f63ddc6afeb3d2c3c7a42add0129547acd61ede)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>
---
 src/plugins/imageformats/svg/qsvgiohandler.cpp | 8 ++++----
 src/svg/qsvgtinydocument.cpp                   | 4 ++--
 2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/src/plugins/imageformats/svg/qsvgiohandler.cpp b/src/plugins/imageformats/svg/qsvgiohandler.cpp
index a999d47..5e96d27 100644
--- a/src/plugins/imageformats/svg/qsvgiohandler.cpp
+++ b/src/plugins/imageformats/svg/qsvgiohandler.cpp
@@ -126,14 +126,14 @@ bool QSvgIOHandler::canRead() const
     if (d->loaded && !d->readDone)
         return true;        // Will happen if we have been asked for the size
 
-    QByteArray buf = device()->peek(8);
+    QByteArray buf = device()->peek(16);
 #ifndef QT_NO_COMPRESS
     if (buf.startsWith("\x1f\x8b")) {
         setFormat("svgz");
         return true;
     } else
 #endif
-    if (buf.contains("<?xml") || buf.contains("<svg") || buf.contains("<!--")) {
+    if (buf.contains("<?xml") || buf.contains("<svg") || buf.contains("<!--") || buf.contains("<!DOCTYPE svg")) {
         setFormat("svg");
         return true;
     }
@@ -267,12 +267,12 @@ bool QSvgIOHandler::supportsOption(ImageOption option) const
 
 bool QSvgIOHandler::canRead(QIODevice *device)
 {
-    QByteArray buf = device->peek(8);
+    QByteArray buf = device->peek(16);
     return
 #ifndef QT_NO_COMPRESS
             buf.startsWith("\x1f\x8b") ||
 #endif
-            buf.contains("<?xml") || buf.contains("<svg") || buf.contains("<!--");
+            buf.contains("<?xml") || buf.contains("<svg") || buf.contains("<!--") || buf.contains("<!DOCTYPE svg");
 }
 
 QT_END_NAMESPACE
diff --git a/src/svg/qsvgtinydocument.cpp b/src/svg/qsvgtinydocument.cpp
index da3d142..38db330 100644
--- a/src/svg/qsvgtinydocument.cpp
+++ b/src/svg/qsvgtinydocument.cpp
@@ -157,8 +157,8 @@ static QByteArray qt_inflateSvgzDataFrom(QIODevice *device, bool doCheckContent)
 
         if (doCheckContent) {
             // Quick format check, equivalent to QSvgIOHandler::canRead()
-            QByteArray buf = destination.left(8);
-            if (!buf.contains("<?xml") && !buf.contains("<svg") && !buf.contains("<!--")) {
+            QByteArray buf = destination.left(16);
+            if (!buf.contains("<?xml") && !buf.contains("<svg") && !buf.contains("<!--") && !buf.contains("<!DOCTYPE svg")) {
                 inflateEnd(&zlibStream);
                 qCWarning(lcSvgHandler, "Error while inflating gzip file: SVG format check failed");
                 return QByteArray();
-- 
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