C++: Finish gcc's include_next support

This implements the actual include_next logic and thus completes

    commit b934cc1
    C++: pass #include_next down to CppPreprocessor::tryIncludeFile

    commmit 140b502
    C++: Highlight argument to gcc's #include_next extension

Based on https://gcc.gnu.org/onlinedocs/cpp/Wrapper-Headers.html

Task-number: QTCREATORBUG-10225
Change-Id: I7eef7f5ea64a114f6d092304d32b72c55c2ce134
Reviewed-by: hjk <hjk121@nokiamail.com>
Reviewed-by: Erik Verbruggen <erik.verbruggen@theqtcompany.com>

src/plugins/coreplugin/testdatadir.h

@@ -52,8 +52,6 @@ class CORE_EXPORT TestDataDir
 public:
     TestDataDir(const QString &directory);
     QString file(const QString &fileName) const;
-
-protected:
     QString directory(const QString &subdir = QString(), bool clean = true) const;
 
 private:

src/plugins/cpptools/cppsourceprocessor.cpp

@@ -272,19 +272,33 @@ QString CppSourceProcessor::resolveFile_helper(const QString &fileName, IncludeT
     if (QFileInfo(fileName).isAbsolute())
         return checkFile(fileName) ? fileName : QString();
 
-    if (type == IncludeLocal && m_currentDoc) {
+    auto headerPathsIt = m_headerPaths.begin();
+    auto headerPathsEnd = m_headerPaths.end();
+    if (m_currentDoc) {
+        if (type == IncludeLocal) {
             const QFileInfo currentFileInfo(m_currentDoc->fileName());
             const QString path = cleanPath(currentFileInfo.absolutePath()) + fileName;
             if (checkFile(path))
                 return path;
             // Fall through! "16.2 Source file inclusion" from the standard states to continue
             // searching as if this would be a global include.
+
+        } else if (type == IncludeNext) {
+            const QFileInfo currentFileInfo(m_currentDoc->fileName());
+            const QString currentDirPath = cleanPath(currentFileInfo.dir().path());
+            for (; headerPathsIt != headerPathsEnd; ++headerPathsIt) {
+                if (headerPathsIt->path == currentDirPath) {
+                    ++headerPathsIt;
+                    break;
+                }
+            }
+        }
     }
 
-    foreach (const ProjectPart::HeaderPath &headerPath, m_headerPaths) {
-        if (headerPath.isFrameworkPath())
+    for (; headerPathsIt != headerPathsEnd; ++headerPathsIt) {
+        if (headerPathsIt->isFrameworkPath())
             continue;
-        const QString path = headerPath.path + fileName;
+        const QString path = headerPathsIt->path + fileName;
         if (m_workingCopy.contains(path) || checkFile(path))
             return path;
     }

src/plugins/cpptools/cppsourceprocessor_test.cpp

@@ -37,6 +37,7 @@
 #include "cpptoolstestcase.h"
 #include "editordocumenthandle.h"
 
+#include <coreplugin/testdatadir.h>
 #include <texteditor/texteditor.h>
 
 #include <cplusplus/CppDocument.h>
@@ -203,3 +204,38 @@ void CppToolsPlugin::test_cppsourceprocessor_macroUses()
     QCOMPARE(macroUse.utf16charsEnd(), 35U);
     QCOMPARE(macroUse.beginLine(), 2U);
 }
+
+static bool isMacroDefinedInDocument(const QByteArray &macroName, const Document::Ptr &document)
+{
+    foreach (const Macro &macro, document->definedMacros()) {
+        if (macro.name() == macroName)
+            return true;
+    }
+
+    return false;
+}
+
+static inline QString _(const QByteArray &ba) { return QString::fromLatin1(ba, ba.size()); }
+
+void CppToolsPlugin::test_cppsourceprocessor_includeNext()
+{
+    const Core::Tests::TestDataDir data(
+        _(SRCDIR "/../../../tests/auto/cplusplus/preprocessor/data/include_next-data/"));
+    const QString mainFilePath = data.file(QLatin1String("main.cpp"));
+    const QString customHeaderPath = data.directory(QLatin1String("customIncludePath"));
+    const QString systemHeaderPath = data.directory(QLatin1String("systemIncludePath"));
+
+    CppSourceProcessor::DocumentCallback documentCallback = [](const CPlusPlus::Document::Ptr &){};
+    CppSourceProcessor sourceProcessor(Snapshot(), documentCallback);
+    ProjectPart::HeaderPaths headerPaths = ProjectPart::HeaderPaths()
+        << ProjectPart::HeaderPath(customHeaderPath, ProjectPart::HeaderPath::IncludePath)
+        << ProjectPart::HeaderPath(systemHeaderPath, ProjectPart::HeaderPath::IncludePath);
+    sourceProcessor.setHeaderPaths(headerPaths);
+
+    sourceProcessor.run(mainFilePath);
+    const Snapshot snapshot = sourceProcessor.snapshot();
+    QVERIFY(!snapshot.isEmpty());
+    const Document::Ptr mainDocument = snapshot.document(mainFilePath);
+    QVERIFY(mainDocument);
+    QVERIFY(isMacroDefinedInDocument("OK_FEATURE_X_ENABLED", mainDocument));
+}

src/plugins/cpptools/cpptoolsplugin.h

@@ -133,6 +133,7 @@ private slots:
     void test_cppsourceprocessor_includes_cyclic();
     void test_cppsourceprocessor_includes_allDiagnostics();
     void test_cppsourceprocessor_macroUses();
+    void test_cppsourceprocessor_includeNext();
 
     void test_functionutils_virtualFunctions();
     void test_functionutils_virtualFunctions_data();

tests/auto/cplusplus/preprocessor/data/include_next-data/customIncludePath/t.h

@@ -0,0 +1,2 @@
+#define ENABLE_FEATURE_X
+#include_next "t.h"

tests/auto/cplusplus/preprocessor/data/include_next-data/main.cpp

@@ -0,0 +1,13 @@
+// Copyright
+
+#include "t.h"
+
+int main()
+{
+#ifdef FEATURE_X_ENABLED
+#define OK_FEATURE_X_ENABLED
+    return 0;
+#endif
+    return 1;
+}
+

tests/auto/cplusplus/preprocessor/data/include_next-data/systemIncludePath/t.h

@@ -0,0 +1,5 @@
+#define SYSTEM_HEADER_INCLUDED
+
+#ifdef ENABLE_FEATURE_X
+#define FEATURE_X_ENABLED
+#endif