Clean up property attributes (2/2)

This commit introduces a new AST node for property attributes (currently
required, default and readonly). That node is not integrated into our
visitors, as it is only meant as an internal implementaion detail of
UiPublicMember. All information stored in it is meant to be accessed by
UiPublicMember's methods (see also the note below).
We use an union of SourceLocation and a node pointer to only pay the
overhead of the new node for properties; signals simply store the signal
token.

The grammar is rewritten with a new UiPropertyAttributes rule, which
avoids quite a bit of duplication in various rules, which had to deal
with the combinatorial explosion of attributes. Some parse errors are
now turned into semantic errors instead (readonly without initializer,
required with initializer).

By centralizing the handling of attributes in the grammar, we now can
easily support e.g. default properties with a list initializer.

As part of this restructuring, UiPublicMember's firstSourceLocation is
fixed to ensure that we actually return the first source location,
independent of the order in which the attributes are written.

Note: In theory, we would not need to make UiPropertyAttributes an AST
node. It could be a simple data class. However, the parser currently
assumes that every pointer in its parser stack is an AST node, and
touching that part would be a larger undertaking. As we use a pool
allocator, the cost is not that high (though we use more memory from the
pool then we would strictly need to).

Change-Id: Ia1d9fd7a6553d443cc57bc3d773f5be0aebe0e0e
Reviewed-by: Ulf Hermann <ulf.hermann@qt.io>

1 files changed, 17 insertions, 0 deletions

diff --git a/src/qml/parser/qqmljsast.cpp b/src/qml/parser/qqmljsast.cpp
index a068a412df..279ed62956 100644
--- a/src/qml/parser/qqmljsast.cpp
+++ b/src/qml/parser/qqmljsast.cpp
@@ -37,12 +37,15 @@
 **
 ****************************************************************************/
 
+#include <QString>
 #include <QLocale>
 #include "qqmljsast_p.h"
 
 #include "qqmljsastvisitor_p.h"
 #include <qlocale.h>
 
+#include <algorithm>
+
 QT_BEGIN_NAMESPACE
 
 namespace QQmlJS { namespace AST {
@@ -1648,6 +1651,20 @@ void UiAnnotation::accept0(BaseVisitor *visitor)
     visitor->endVisit(this);
 }
 
+SourceLocation UiPropertyAttributes::firstSourceLocation() const
+{
+    std::array<const SourceLocation *, 4> tokens {&m_propertyToken, &m_defaultToken, &m_readonlyToken, &m_requiredToken};
+    const auto it = std::min_element(tokens.begin(), tokens.end(), compareLocationsByBegin<true>);
+    return **it;
+}
+
+SourceLocation UiPropertyAttributes::lastSourceLocation() const
+{
+    std::array<const SourceLocation *, 4> tokens {&m_propertyToken, &m_defaultToken, &m_readonlyToken, &m_requiredToken};
+    const auto it = std::max_element(tokens.begin(), tokens.end(), compareLocationsByBegin<false>);
+    return **it;
+}
+
 } } // namespace QQmlJS::AST
 
 QT_END_NAMESPACE