1 files changed, 86 insertions, 0 deletions
diff --git a/src/qml/qmldirparser/qqmlimportresolver.cpp b/src/qml/qmldirparser/qqmlimportresolver.cpp
new file mode 100644
index 0000000000..15ec7765b0
--- /dev/null
+++ b/src/qml/qmldirparser/qqmlimportresolver.cpp
@@ -0,0 +1,86 @@
+// Copyright (C) 2020 The Qt Company Ltd.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
+
+#include "qqmlimportresolver_p.h"
+
+QT_BEGIN_NAMESPACE
+
+enum ImportVersion { FullyVersioned, PartiallyVersioned, Unversioned };
+
+/*
+    Forms complete paths to a module, from a list of base paths,
+    a module URI and version specification.
+
+    For example, QtQml.Models 2.0:
+    - base/QtQml/Models.2.0
+    - base/QtQml.2.0/Models
+    - base/QtQml/Models.2
+    - base/QtQml.2/Models
+    - base/QtQml/Models
+*/
+QStringList qQmlResolveImportPaths(QStringView uri, const QStringList &basePaths,
+                                   QTypeRevision version)
+{
+    static const QLatin1Char Slash('/');
+    static const QLatin1Char Backslash('\\');
+
+    const QVector<QStringView> parts = uri.split(u'.', Qt::SkipEmptyParts);
+
+    QStringList importPaths;
+    // fully & partially versioned parts + 1 unversioned for each base path
+    importPaths.reserve(2 * parts.size() + 1);
+
+    auto versionString = [](QTypeRevision version, ImportVersion mode)
+    {
+        if (mode == FullyVersioned) {
+            // extension with fully encoded version number (eg. MyModule.3.2)
+            return QString::fromLatin1(".%1.%2").arg(version.majorVersion())
+                    .arg(version.minorVersion());
+        }
+        if (mode == PartiallyVersioned) {
+            // extension with encoded version major (eg. MyModule.3)
+            return QString::fromLatin1(".%1").arg(version.majorVersion());
+        }
+        // else extension without version number (eg. MyModule)
+        return QString();
+    };
+
+    auto joinStringRefs = [](const QVector<QStringView> &refs, const QChar &sep) {
+        QString str;
+        for (auto it = refs.cbegin(); it != refs.cend(); ++it) {
+            if (it != refs.cbegin())
+                str += sep;
+            str += *it;
+        }
+        return str;
+    };
+
+    const ImportVersion initial = (version.hasMinorVersion())
+            ? FullyVersioned
+            : (version.hasMajorVersion() ? PartiallyVersioned : Unversioned);
+    for (int mode = initial; mode <= Unversioned; ++mode) {
+        const QString ver = versionString(version, ImportVersion(mode));
+
+        for (const QString &path : basePaths) {
+            QString dir = path;
+            if (!dir.endsWith(Slash) && !dir.endsWith(Backslash))
+                dir += Slash;
+
+            // append to the end
+            importPaths += dir + joinStringRefs(parts, Slash) + ver;
+
+            if (mode != Unversioned) {
+                // insert in the middle
+                for (int index = parts.size() - 2; index >= 0; --index) {
+                    importPaths += dir + joinStringRefs(parts.mid(0, index + 1), Slash)
+                            + ver + Slash
+                            + joinStringRefs(parts.mid(index + 1), Slash);
+                }
+            }
+        }
+    }
+
+    return importPaths;
+}
+
+QT_END_NAMESPACE