3 files changed, 30 insertions, 2 deletions
diff --git a/src/google/protobuf/compiler/command_line_interface.cc b/src/google/protobuf/compiler/command_line_interface.cc
index ea8c4ab2..089844f4 100644
--- a/src/google/protobuf/compiler/command_line_interface.cc
+++ b/src/google/protobuf/compiler/command_line_interface.cc
@@ -93,7 +93,8 @@ static const char* kPathSeparator = ":";
 #endif
 
 // Returns true if the text looks like a Windows-style absolute path, starting
-// with a drive letter.  Example:  "C:\foo".
+// with a drive letter.  Example:  "C:\foo".  TODO(kenton):  Share this with
+// copy in importer.cc?
 static bool IsWindowsAbsolutePath(const string& text) {
 #if defined(_WIN32) || defined(__CYGWIN__)
   return text.size() >= 3 && text[1] == ':' &&
diff --git a/src/google/protobuf/compiler/importer.cc b/src/google/protobuf/compiler/importer.cc
index a0d8164a..30e106e8 100644
--- a/src/google/protobuf/compiler/importer.cc
+++ b/src/google/protobuf/compiler/importer.cc
@@ -61,6 +61,20 @@ namespace compiler {
 #endif
 #endif
 
+// Returns true if the text looks like a Windows-style absolute path, starting
+// with a drive letter.  Example:  "C:\foo".  TODO(kenton):  Share this with
+// copy in command_line_interface.cc?
+static bool IsWindowsAbsolutePath(const string& text) {
+#if defined(_WIN32) || defined(__CYGWIN__)
+  return text.size() >= 3 && text[1] == ':' &&
+         isalpha(text[0]) &&
+         (text[2] == '/' || text[2] == '\\') &&
+         text.find_last_of(':') == 1;
+#else
+  return false;
+#endif
+}
+
 MultiFileErrorCollector::~MultiFileErrorCollector() {}
 
 // This class serves two purposes:
@@ -276,7 +290,8 @@ static bool ApplyMapping(const string& filename,
       // We do not allow the file name to use "..".
       return false;
     }
-    if (HasPrefixString(filename, "/")) {
+    if (HasPrefixString(filename, "/") ||
+        IsWindowsAbsolutePath(filename)) {
       // This is an absolute path, so it isn't matched by the empty string.
       return false;
     }
diff --git a/src/google/protobuf/compiler/importer_unittest.cc b/src/google/protobuf/compiler/importer_unittest.cc
index 173a3373..51aeb90c 100644
--- a/src/google/protobuf/compiler/importer_unittest.cc
+++ b/src/google/protobuf/compiler/importer_unittest.cc
@@ -516,6 +516,18 @@ TEST_F(DiskSourceTreeTest, DiskFileToVirtualFileCanonicalization) {
     source_tree_.DiskFileToVirtualFile(
       "../../baz", &virtual_file, &shadowing_disk_file));
 
+  // "/foo" is not mapped (it should not be misintepreted as being under ".").
+  EXPECT_EQ(DiskSourceTree::NO_MAPPING,
+    source_tree_.DiskFileToVirtualFile(
+      "/foo", &virtual_file, &shadowing_disk_file));
+
+#ifdef WIN32
+  // "C:\foo" is not mapped (it should not be misintepreted as being under ".").
+  EXPECT_EQ(DiskSourceTree::NO_MAPPING,
+    source_tree_.DiskFileToVirtualFile(
+      "C:\\foo", &virtual_file, &shadowing_disk_file));
+#endif  // WIN32
+
   // But "../baz" should be.
   EXPECT_EQ(DiskSourceTree::CANNOT_OPEN,
     source_tree_.DiskFileToVirtualFile(