Delay loading implicit import

As a performance improvement to avoid accessing the filesystem
unecessarily, only import "." implicitly if types cannot be found in the
existing imports. This is not a behavior change for type resolution,
because "." already has the lowest precedence for type resolution.

Change-Id: I8a8f10f7a790e6a02fc2c07c443f7be1984fc979
Reviewed-by: Matthew Vogt <matthew.vogt@qinetic.com.au>
Reviewed-by: Christopher Adams <chris.adams@jollamobile.com>

6 files changed, 98 insertions, 36 deletions

diff --git a/src/declarative/qml/qdeclarativeimport.cpp b/src/declarative/qml/qdeclarativeimport.cpp
index 20331786..db062e47 100644
--- a/src/declarative/qml/qdeclarativeimport.cpp
+++ b/src/declarative/qml/qdeclarativeimport.cpp
@@ -441,6 +441,13 @@ bool QDeclarativeImportsPrivate::add(const QDeclarativeDirComponents &qmldircomp
             set.insert(prefix,(s=new QDeclarativeImportedNamespace));
     }
 
+    bool appendInstead = false;
+    if (importType == QDeclarativeScriptParser::Import::Implicit) {
+        //Treat same as a File import, but lower precedence
+        appendInstead = true;
+        importType = QDeclarativeScriptParser::Import::File;
+    }
+
     QString url = uri;
     bool versionFound = false;
     if (importType == QDeclarativeScriptParser::Import::Library) {
@@ -588,12 +595,21 @@ bool QDeclarativeImportsPrivate::add(const QDeclarativeDirComponents &qmldircomp
         }
     }
 
-    s->uris.prepend(uri);
-    s->urls.prepend(url);
-    s->majversions.prepend(vmaj);
-    s->minversions.prepend(vmin);
-    s->isLibrary.prepend(importType == QDeclarativeScriptParser::Import::Library);
-    s->qmlDirComponents.prepend(qmldircomponents);
+    if (appendInstead) {
+        s->uris.append(uri);
+        s->urls.append(url);
+        s->majversions.append(vmaj);
+        s->minversions.append(vmin);
+        s->isLibrary.append(importType == QDeclarativeScriptParser::Import::Library);
+        s->qmlDirComponents.append(qmldircomponents);
+    } else {
+        s->uris.prepend(uri);
+        s->urls.prepend(url);
+        s->majversions.prepend(vmaj);
+        s->minversions.prepend(vmin);
+        s->isLibrary.prepend(importType == QDeclarativeScriptParser::Import::Library);
+        s->qmlDirComponents.prepend(qmldircomponents);
+    }
     return true;
 }
 
diff --git a/src/declarative/qml/qdeclarativescriptparser_p.h b/src/declarative/qml/qdeclarativescriptparser_p.h
index 671326a2..0d02aba5 100644
--- a/src/declarative/qml/qdeclarativescriptparser_p.h
+++ b/src/declarative/qml/qdeclarativescriptparser_p.h
@@ -75,7 +75,7 @@ public:
     public:
         Import() : type(Library) {}
 
-        enum Type { Library, File, Script };
+        enum Type { Library, File, Script, Implicit }; //Implicit is only used internally
         Type type;
 
         QString uri;
diff --git a/src/declarative/qml/qdeclarativetypeloader.cpp b/src/declarative/qml/qdeclarativetypeloader.cpp
index 012afb39..135bff89 100644
--- a/src/declarative/qml/qdeclarativetypeloader.cpp
+++ b/src/declarative/qml/qdeclarativetypeloader.cpp
@@ -1055,19 +1055,6 @@ void QDeclarativeTypeData::resolveTypes()
     QDeclarativeEnginePrivate *ep = QDeclarativeEnginePrivate::get(m_typeLoader->engine());
     QDeclarativeImportDatabase *importDatabase = &ep->importDatabase;
 
-    // For local urls, add an implicit import "." as first (most overridden) lookup. 
-    // This will also trigger the loading of the qmldir and the import of any native 
-    // types from available plugins.
-    if (QDeclarativeQmldirData *qmldir = qmldirForUrl(finalUrl().resolved(QUrl(QLatin1String("./qmldir"))))) {
-        m_imports.addImport(importDatabase, QLatin1String("."),
-                            QString(), -1, -1, QDeclarativeScriptParser::Import::File, 
-                            qmldir->dirComponents(), 0);
-    } else {
-        m_imports.addImport(importDatabase, QLatin1String("."), 
-                            QString(), -1, -1, QDeclarativeScriptParser::Import::File, 
-                            QDeclarativeDirComponents(), 0);
-    }
-
     foreach (const QDeclarativeScriptParser::Import &import, scriptParser.imports()) {
         QDeclarativeDirComponents qmldircomponentsnetwork;
         if (import.type == QDeclarativeScriptParser::Import::Script)
@@ -1107,6 +1094,7 @@ void QDeclarativeTypeData::resolveTypes()
         }
     }
 
+    bool implicitImportLoaded = false;
     foreach (QDeclarativeScriptParser::TypeReference *parserRef, scriptParser.referencedTypes()) {
         QByteArray typeName = parserRef->name.toUtf8();
 
@@ -1123,23 +1111,49 @@ void QDeclarativeTypeData::resolveTypes()
             // Known to not be a type:
             //  - known to be a namespace (Namespace {})
             //  - type with unknown namespace (UnknownNamespace.SomeType {})
-            QDeclarativeError error;
-            error.setUrl(m_imports.baseUrl());
-            QString userTypeName = parserRef->name;
-            userTypeName.replace(QLatin1Char('/'),QLatin1Char('.'));
-            if (typeNamespace)
-                error.setDescription(QDeclarativeTypeLoader::tr("Namespace %1 cannot be used as a type").arg(userTypeName));
-            else
-                error.setDescription(QDeclarativeTypeLoader::tr("%1 %2").arg(userTypeName).arg(errorString));
-
-            if (!parserRef->refObjects.isEmpty()) {
-                QDeclarativeParser::Object *obj = parserRef->refObjects.first();
-                error.setLine(obj->location.start.line);
-                error.setColumn(obj->location.start.column);
+            bool typeFound = false;
+
+            if (!typeNamespace && !implicitImportLoaded) {
+                implicitImportLoaded = true;
+                // For local urls, add an implicit import "." as most overridden lookup.
+                // This will also trigger the loading of the qmldir and the import of any native
+                // types from available plugins.
+                // This is only done if the type is not otherwise found, side effects of plugin loading may be avoided
+                // ### This should be an acceptable variation because A) It's only side effects (and img providers) B) You shouldn't be doing that in "." anyways!
+                if (QDeclarativeQmldirData *qmldir = qmldirForUrl(finalUrl().resolved(QUrl(QLatin1String("./qmldir"))))) {
+                    m_imports.addImport(importDatabase, QLatin1String("."),
+                                        QString(), -1, -1, QDeclarativeScriptParser::Import::Implicit,
+                                        qmldir->dirComponents(), 0);
+                } else {
+                    m_imports.addImport(importDatabase, QLatin1String("."),
+                                        QString(), -1, -1, QDeclarativeScriptParser::Import::Implicit,
+                                        QDeclarativeDirComponents(), 0);
+                }
+                if (m_imports.resolveType(typeName, &ref.type, &url, &majorVersion, &minorVersion,
+                                           &typeNamespace, &errorString) || typeNamespace) {
+                    typeFound = true;
+                }
+            }
+
+            if (!typeFound) {
+                QDeclarativeError error;
+                error.setUrl(m_imports.baseUrl());
+                QString userTypeName = parserRef->name;
+                userTypeName.replace(QLatin1Char('/'),QLatin1Char('.'));
+                if (typeNamespace)
+                    error.setDescription(QDeclarativeTypeLoader::tr("Namespace %1 cannot be used as a type").arg(userTypeName));
+                else
+                    error.setDescription(QDeclarativeTypeLoader::tr("%1 %2").arg(userTypeName).arg(errorString));
+
+                if (!parserRef->refObjects.isEmpty()) {
+                    QDeclarativeParser::Object *obj = parserRef->refObjects.first();
+                    error.setLine(obj->location.start.line);
+                    error.setColumn(obj->location.start.column);
+                }
+
+                setError(error);
+                return;
             }
-            
-            setError(error);
-            return;
         }
 
         if (ref.type) {
diff --git a/tests/auto/declarative/qdeclarativelanguage/data/LocalLast2.qml b/tests/auto/declarative/qdeclarativelanguage/data/LocalLast2.qml
new file mode 100644
index 00000000..4bf7eb2e
--- /dev/null
+++ b/tests/auto/declarative/qdeclarativelanguage/data/LocalLast2.qml
@@ -0,0 +1,2 @@
+import QtQuick 1.0
+MouseArea {}
diff --git a/tests/auto/declarative/qdeclarativelanguage/data/localOrderTest.qml b/tests/auto/declarative/qdeclarativelanguage/data/localOrderTest.qml
new file mode 100644
index 00000000..bdb13756
--- /dev/null
+++ b/tests/auto/declarative/qdeclarativelanguage/data/localOrderTest.qml
@@ -0,0 +1,7 @@
+import QtQuick 1.0
+import com.nokia.installedtest 1.0
+
+LocalLast2 {
+    property Item item: LocalLast {}
+}
+
diff --git a/tests/auto/declarative/qdeclarativelanguage/tst_qdeclarativelanguage.cpp b/tests/auto/declarative/qdeclarativelanguage/tst_qdeclarativelanguage.cpp
index e201807b..edbfeeb8 100644
--- a/tests/auto/declarative/qdeclarativelanguage/tst_qdeclarativelanguage.cpp
+++ b/tests/auto/declarative/qdeclarativelanguage/tst_qdeclarativelanguage.cpp
@@ -132,6 +132,7 @@ private slots:
     void reservedWords();
     void inlineAssignmentsOverrideBindings();
     void nestedComponentRoots();
+    void implicitImportsLast();
 
     void basicRemote_data();
     void basicRemote();
@@ -1806,6 +1807,11 @@ void tst_qdeclarativelanguage::importsOrder_data()
            "LocalLast {}"
            << (!qmlCheckTypes()?"QDeclarativeRectangle":"")// i.e. from com.nokia.installedtest, not data/LocalLast.qml
            << (!qmlCheckTypes()?"":"LocalLast is ambiguous. Found in lib/com/nokia/installedtest and in local directory");
+    QTest::newRow("local last 3") <<
+           "import com.nokia.installedtest 1.0\n"
+           "LocalLast {LocalLast2{}}"
+           << (!qmlCheckTypes()?"QDeclarativeRectangle":"")// i.e. from com.nokia.installedtest, not data/LocalLast.qml
+           << (!qmlCheckTypes()?"":"LocalLast is ambiguous. Found in lib/com/nokia/installedtest and in local directory");
 }
 
 void tst_qdeclarativelanguage::importsOrder()
@@ -2021,6 +2027,23 @@ void tst_qdeclarativelanguage::compatibilitySemicolon()
     QVERIFY(o != 0);
 }
 
+// Tests that the implicit import has lowest precedence, in the case where
+// there are conflicting types and types only found in the local import.
+// Tests that just check one (or the root) type are in ::importsOrder
+void tst_qdeclarativelanguage::implicitImportsLast()
+{
+    if (qmlCheckTypes())
+        QSKIP("This test is about maintaining the same choice when type is ambiguous.");
+    QDeclarativeComponent component(&engine, testFileUrl("localOrderTest.qml"));
+    VERIFY_ERRORS(0);
+    QObject *object = qobject_cast<QObject *>(component.create());
+    QVERIFY(object != 0);
+    QVERIFY(QString(object->metaObject()->className()).startsWith(QLatin1String("QDeclarativeMouseArea")));
+    QObject* object2 = object->property("item").value<QObject*>();
+    QVERIFY(object2 != 0);
+    QCOMPARE(QString(object2->metaObject()->className()), QLatin1String("QDeclarativeRectangle"));
+}
+
 QTEST_MAIN(tst_qdeclarativelanguage)
 
 #include "tst_qdeclarativelanguage.moc"