Fix check of filename length

CMakeLists.txt

@@ -246,7 +246,8 @@ if(BUILD_TESTING)
     src/util_test.cc
   )
   if(WIN32)
-    target_sources(ninja_test PRIVATE src/includes_normalize_test.cc src/msvc_helper_test.cc)
+    target_sources(ninja_test PRIVATE src/includes_normalize_test.cc src/msvc_helper_test.cc
+      windows/ninja.manifest)
   endif()
   target_link_libraries(ninja_test PRIVATE libninja libninja-re2c)
 

src/disk_interface.cc

@@ -26,6 +26,7 @@
 #include <sstream>
 #include <windows.h>
 #include <direct.h>  // _mkdir
+#include <atlcore.h>
 #else
 #include <unistd.h>
 #endif
@@ -157,13 +158,27 @@ bool DiskInterface::MakeDirs(const string& path) {
 }
 
 // RealDiskInterface -----------------------------------------------------------
+RealDiskInterface::RealDiskInterface() 
+#ifdef _WIN32
+: use_cache_(false), long_paths_enabled_(false) {
+  setlocale(LC_ALL, "");
+  IFDYNAMICGETCACHEDFUNCTIONTYPEDEF(L"ntdll", BOOLEAN(WINAPI*)(),
+    "RtlAreLongPathsEnabled",
+    RtlAreLongPathsEnabled) {
+    long_paths_enabled_ = RtlAreLongPathsEnabled();
+  }
+}
+#else
+{}
+#endif
 
 TimeStamp RealDiskInterface::Stat(const string& path, string* err) const {
   METRIC_RECORD("node stat");
 #ifdef _WIN32
   // MSDN: "Naming Files, Paths, and Namespaces"
   // http://msdn.microsoft.com/en-us/library/windows/desktop/aa365247(v=vs.85).aspx
-  if (!path.empty() && path[0] != '\\' && path.size() > MAX_PATH) {
+  if (!path.empty() && !AreLongPathsEnabled() && path[0] != '\\' &&
+      path.size() > MAX_PATH) {
     ostringstream err_stream;
     err_stream << "Stat(" << path << "): Filename longer than " << MAX_PATH
                << " characters";
@@ -333,3 +348,9 @@ void RealDiskInterface::AllowStatCache(bool allow) {
     cache_.clear();
 #endif
 }
+
+#ifdef _WIN32
+bool RealDiskInterface::AreLongPathsEnabled(void) const {
+  return long_paths_enabled_;
+}
+#endif

src/disk_interface.h

@@ -69,11 +69,7 @@ struct DiskInterface: public FileReader {
 
 /// Implementation of DiskInterface that actually hits the disk.
 struct RealDiskInterface : public DiskInterface {
-  RealDiskInterface()
-#ifdef _WIN32
-                      : use_cache_(false)
-#endif
-                      {}
+  RealDiskInterface();
   virtual ~RealDiskInterface() {}
   virtual TimeStamp Stat(const std::string& path, std::string* err) const;
   virtual bool MakeDir(const std::string& path);
@@ -85,11 +81,19 @@ struct RealDiskInterface : public DiskInterface {
   /// Whether stat information can be cached.  Only has an effect on Windows.
   void AllowStatCache(bool allow);
 
+#ifdef _WIN32
+  /// Whether long paths are enabled.  Only has an effect on Windows.
+  bool AreLongPathsEnabled() const;
+#endif
+
  private:
 #ifdef _WIN32
   /// Whether stat information can be cached.
   bool use_cache_;
 
+  /// Whether long paths are enabled.
+  bool long_paths_enabled_;
+
   typedef std::map<std::string, TimeStamp> DirCache;
   // TODO: Neither a map nor a hashmap seems ideal here.  If the statcache
   // works out, come up with a better data structure.

src/disk_interface_test.cc

@@ -17,6 +17,7 @@
 #ifdef _WIN32
 #include <io.h>
 #include <windows.h>
+#include <direct.h>
 #endif
 
 #include "disk_interface.h"
@@ -96,6 +97,24 @@ TEST_F(DiskInterfaceTest, StatExistingFile) {
   EXPECT_EQ("", err);
 }
 
+#ifdef _WIN32
+TEST_F(DiskInterfaceTest, StatExistingFileWithLongPath) {
+  string err;
+  char currentdir[32767];
+  _getcwd(currentdir, sizeof(currentdir));
+  const string filename = string(currentdir) +
+"\\filename_with_256_characters_xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx\
+xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx\
+xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx\
+xxxxxxxxxxxxxxxxxxxxx";
+  const string prefixed = "\\\\?\\" + filename;
+  ASSERT_TRUE(Touch(prefixed.c_str()));
+  EXPECT_GT(disk_.Stat(disk_.AreLongPathsEnabled() ?
+    filename : prefixed, &err), 1);
+  EXPECT_EQ("", err);
+}
+#endif
+
 TEST_F(DiskInterfaceTest, StatExistingDir) {
   string err;
   ASSERT_TRUE(disk_.MakeDir("subdir"));