From c4f1a676fcaad76829c7cda1f5bea018150b7412 Mon Sep 17 00:00:00 2001
From: Simon Hausmann <simon.hausmann@qt.io>
Date: Mon, 22 Jan 2018 12:28:43 +0100
Subject: Fix crash in tst_controls in QQC2

Handle startsWithUpper() for complex sub-strings

Change-Id: Ia7494a880612761ee3caf9113c2ac5faa4edd182
Reviewed-by: Lars Knoll <lars.knoll@qt.io>
---
 src/qml/jsruntime/qv4string.cpp | 21 +++++++++++++++++++++
 src/qml/jsruntime/qv4string_p.h |  7 +++----
 2 files changed, 24 insertions(+), 4 deletions(-)

(limited to 'src/qml')

diff --git a/src/qml/jsruntime/qv4string.cpp b/src/qml/jsruntime/qv4string.cpp
index 932ccf13ef..40280534c4 100644
--- a/src/qml/jsruntime/qv4string.cpp
+++ b/src/qml/jsruntime/qv4string.cpp
@@ -181,6 +181,27 @@ void Heap::String::simplifyString() const
     subtype = StringType_Unknown;
 }
 
+bool Heap::String::startsWithUpper() const
+{
+    if (subtype == StringType_AddedString)
+        return static_cast<const Heap::ComplexString *>(this)->left->startsWithUpper();
+
+    const Heap::String *str = this;
+    int offset = 0;
+    if (subtype == StringType_SubString) {
+        const ComplexString *cs = static_cast<const Heap::ComplexString *>(this);
+        if (!cs->len)
+            return false;
+        // simplification here is not ideal, but hopefully not a common case.
+        if (cs->left->subtype >= Heap::String::StringType_Complex)
+            cs->left->simplifyString();
+        str = cs->left;
+        offset = cs->from;
+    }
+    Q_ASSERT(str->subtype < Heap::String::StringType_Complex);
+    return str->text->size > offset && QChar::isUpper(str->text->data()[offset]);
+}
+
 void Heap::String::append(const String *data, QChar *ch)
 {
     std::vector<const String *> worklist;
diff --git a/src/qml/jsruntime/qv4string_p.h b/src/qml/jsruntime/qv4string_p.h
index 41039bca88..679cb7329c 100644
--- a/src/qml/jsruntime/qv4string_p.h
+++ b/src/qml/jsruntime/qv4string_p.h
@@ -112,6 +112,8 @@ struct Q_QML_PRIVATE_EXPORT String : Base {
         return toQString() == other->toQString();
     }
 
+    bool startsWithUpper() const;
+
     mutable QStringData *text;
     mutable Identifier *identifier;
     mutable uint subtype;
@@ -206,10 +208,7 @@ struct Q_QML_PRIVATE_EXPORT String : public Managed {
         return calculateHashValue(ch, end, subtype);
     }
 
-    bool startsWithUpper() const {
-        Q_ASSERT(d()->subtype < Heap::String::StringType_Complex);
-        return d()->text->size && QChar::isUpper(d()->text->data()[0]);
-    }
+    bool startsWithUpper() const { return d()->startsWithUpper(); }
 
     Identifier *identifier() const { return d()->identifier; }
 
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