Merge the C/C++ include scanners

We had one scanner for every type of file in the C family, all of which
collected the same set of includes, but under a different entry in the
scanner cache. Thus, lots of header files were unnecessarily re-scanned.
We fix this by making the scanner plugins declare a *list* of tags they
can handle and passing the currently active tags in the open() function.

========== Performance data for Rule Execution ==========
    Old instruction count: 3775190973
    New instruction count: 3441085735
    Relative change: -9 %
    Old peak memory usage: 18174216 Bytes
    New peak memory usage: 17307600 Bytes
    Relative change: -5 %

Change-Id: I222d1ec4bbfbc06ecd8c81faa55a500bc0da1ee6
Reviewed-by: Joerg Bornemann <joerg.bornemann@qt.io>

3 files changed, 22 insertions, 117 deletions

diff --git a/src/plugins/scanner/cpp/cppscanner.cpp b/src/plugins/scanner/cpp/cppscanner.cpp
index b95abe3ad..53ce93e32 100644
--- a/src/plugins/scanner/cpp/cppscanner.cpp
+++ b/src/plugins/scanner/cpp/cppscanner.cpp
@@ -59,6 +59,8 @@ using namespace CPlusPlus;
 #include <QtCore/QString>
 #include <QtCore/QLatin1Literal>
 
+#include <cstring>
+
 struct ScanResult
 {
     char *fileName;
@@ -198,11 +200,20 @@ static void scanCppFile(void *opaq, CPlusPlus::Lexer &yylex, bool scanForFileTag
     }
 }
 
-static Opaq *openScanner(const unsigned short *filePath, Opaq::FileType fileType, int flags)
+static void *openScanner(const unsigned short *filePath, const char *fileTags, int flags)
 {
     QScopedPointer<Opaq> opaque(new Opaq);
     opaque->fileName = QString::fromUtf16(filePath);
-    opaque->fileType = fileType;
+    const QList<QByteArray> &tagList = QByteArray::fromRawData(fileTags,
+                                                               std::strlen(fileTags)).split(',');
+    if (tagList.contains("hpp"))
+        opaque->fileType = Opaq::FT_HPP;
+    else if (tagList.contains("cpp"))
+        opaque->fileType = Opaq::FT_CPP;
+    else if (tagList.contains("objcpp"))
+        opaque->fileType = Opaq::FT_OBJCPP;
+    else
+        opaque->fileType = Opaq::FT_UNKNOWN;
 
     size_t mapl = 0;
 #ifdef Q_OS_UNIX
@@ -241,12 +252,6 @@ static Opaq *openScanner(const unsigned short *filePath, Opaq::FileType fileType
     return opaque.take();
 }
 
-template <typename Opaq::FileType t>
-static void *openScannerT(const unsigned short *filePath, int flags)
-{
-    return openScanner(filePath, t, flags);
-}
-
 static void closeScanner(void *ptr)
 {
     Opaq *opaque = static_cast<Opaq *>(ptr);
@@ -293,120 +298,18 @@ static const char **additionalFileTags(void *opaq, int *size)
 
 extern "C" {
 
-ScannerPlugin hppScanner =
-{
-    "include_scanner",
-    "hpp",
-    openScannerT<Opaq::FT_HPP>,
-    closeScanner,
-    next,
-    additionalFileTags,
-    ScannerUsesCppIncludePaths | ScannerRecursiveDependencies
-};
-
-ScannerPlugin cppScanner =
-{
-    "include_scanner",
-    "cpp",
-    openScannerT<Opaq::FT_CPP>,
-    closeScanner,
-    next,
-    additionalFileTags,
-    ScannerUsesCppIncludePaths | ScannerRecursiveDependencies
-};
-
-ScannerPlugin pchCppScanner =
+ScannerPlugin includeScanner =
 {
     "include_scanner",
-    "cpp_pch_src",
-    openScannerT<Opaq::FT_HPP>,
+    "hpp,cpp,cpp_pch_src,c,c_pch_src,objcpp,objcpp_pch_src,objc,objc_pch_src",
+    openScanner,
     closeScanner,
     next,
     additionalFileTags,
     ScannerUsesCppIncludePaths | ScannerRecursiveDependencies
 };
 
-ScannerPlugin cScanner =
-{
-    "include_scanner",
-    "c",
-    openScannerT<Opaq::FT_C>,
-    closeScanner,
-    next,
-    0,
-    ScannerUsesCppIncludePaths | ScannerRecursiveDependencies
-};
-
-ScannerPlugin pchCScanner =
-{
-    "include_scanner",
-    "c_pch_src",
-    openScannerT<Opaq::FT_HPP>,
-    closeScanner,
-    next,
-    additionalFileTags,
-    ScannerUsesCppIncludePaths | ScannerRecursiveDependencies
-};
-
-ScannerPlugin objcppScanner =
-{
-    "include_scanner",
-    "objcpp",
-    openScannerT<Opaq::FT_OBJCPP>,
-    closeScanner,
-    next,
-    additionalFileTags,
-    ScannerUsesCppIncludePaths | ScannerRecursiveDependencies
-};
-
-ScannerPlugin pchObjcppScanner =
-{
-    "include_scanner",
-    "objcpp_pch_src",
-    openScannerT<Opaq::FT_HPP>,
-    closeScanner,
-    next,
-    additionalFileTags,
-    ScannerUsesCppIncludePaths | ScannerRecursiveDependencies
-};
-
-ScannerPlugin objcScanner =
-{
-    "include_scanner",
-    "objc",
-    openScannerT<Opaq::FT_OBJC>,
-    closeScanner,
-    next,
-    additionalFileTags,
-    ScannerUsesCppIncludePaths | ScannerRecursiveDependencies
-};
-
-ScannerPlugin pchObjcScanner =
-{
-    "include_scanner",
-    "objc_pch_src",
-    openScannerT<Opaq::FT_HPP>,
-    closeScanner,
-    next,
-    additionalFileTags,
-    ScannerUsesCppIncludePaths | ScannerRecursiveDependencies
-};
-
-ScannerPlugin rcScanner =
-{
-    "include_scanner",
-    "rc",
-    openScannerT<Opaq::FT_RC>,
-    closeScanner,
-    next,
-    0,
-    ScannerUsesCppIncludePaths | ScannerRecursiveDependencies
-};
-
-ScannerPlugin *cppScanners[] = {
-    &hppScanner, &pchCppScanner, &pchCScanner, &pchObjcppScanner, &pchObjcScanner,
-    &cppScanner, &cScanner, &objcppScanner, &objcScanner, &rcScanner, NULL
-};
+ScannerPlugin *cppScanners[] = { &includeScanner, NULL };
 
 #ifndef QBS_STATIC_LIB
 CPPSCANNER_EXPORT ScannerPlugin **getScanners()
diff --git a/src/plugins/scanner/qt/qtscanner.cpp b/src/plugins/scanner/qt/qtscanner.cpp
index 4cd77b8af..0374fc373 100644
--- a/src/plugins/scanner/qt/qtscanner.cpp
+++ b/src/plugins/scanner/qt/qtscanner.cpp
@@ -97,9 +97,10 @@ struct OpaqQrc
     }
 };
 
-static void *openScannerQrc(const unsigned short *filePath, int flags)
+static void *openScannerQrc(const unsigned short *filePath, const char *fileTags, int flags)
 {
     Q_UNUSED(flags);
+    Q_UNUSED(fileTags);
     QScopedPointer<OpaqQrc> opaque(new OpaqQrc);
 
 #ifdef Q_OS_UNIX
diff --git a/src/plugins/scanner/scanner.h b/src/plugins/scanner/scanner.h
index f97ebf81b..7843ceec5 100644
--- a/src/plugins/scanner/scanner.h
+++ b/src/plugins/scanner/scanner.h
@@ -56,10 +56,11 @@ enum OpenScannerFlags
 /**
   * Open a file that's going to be scanned.
   * The file path encoding is UTF-16 on all platforms.
+  * The file tags are in CSV format.
   *
   * Returns a scanner handle.
   */
-typedef void *(*scanOpen_f) (const unsigned short *filePath, int flags);
+typedef void *(*scanOpen_f) (const unsigned short *filePath, const char *fileTags, int flags);
 
 /**
   * Closes the given scanner handle.
@@ -91,7 +92,7 @@ class ScannerPlugin
 {
 public:
     const char  *name;
-    const char  *fileTag;
+    const char  *fileTags; // CSV
     scanOpen_f  open;
     scanClose_f close;
     scanNext_f  next;