Bazel client: SplitPath works with Windows paths

This allows correct behavior of Dirname and
Basename on Windows.

See https://github.com/bazelbuild/bazel/issues/2107

--
PiperOrigin-RevId: 142441234
MOS_MIGRATED_REVID=142441234

7 files changed, 186 insertions, 12 deletions

diff --git a/src/main/cpp/util/file.cc b/src/main/cpp/util/file.cc
index 2f6e6c66f2..392af372af 100644
--- a/src/main/cpp/util/file.cc
+++ b/src/main/cpp/util/file.cc
@@ -69,18 +69,6 @@ bool WriteFile(const std::string &content, const std::string &filename) {
   return WriteFile(content.c_str(), content.size(), filename);
 }
 
-pair<string, string> SplitPath(const string &path) {
-  size_t pos = path.rfind('/');
-
-  // Handle the case with no '/' in 'path'.
-  if (pos == string::npos) return std::make_pair("", path);
-
-  // Handle the case with a single leading '/' in 'path'.
-  if (pos == 0) return std::make_pair(string(path, 0, 1), string(path, 1));
-
-  return std::make_pair(string(path, 0, pos), string(path, pos + 1));
-}
-
 string Dirname(const string &path) {
   return SplitPath(path).first;
 }
diff --git a/src/main/cpp/util/file_platform.h b/src/main/cpp/util/file_platform.h
index 1db579a494..78322dfeb8 100644
--- a/src/main/cpp/util/file_platform.h
+++ b/src/main/cpp/util/file_platform.h
@@ -26,6 +26,9 @@ class IPipe;
 
 IPipe* CreatePipe();
 
+// Split a path to dirname and basename parts.
+std::pair<std::string, std::string> SplitPath(const std::string &path);
+
 // Replaces 'content' with contents of file 'filename'.
 // If `max_size` is positive, the method reads at most that many bytes;
 // otherwise the method reads the whole file.
diff --git a/src/main/cpp/util/file_posix.cc b/src/main/cpp/util/file_posix.cc
index e197a09453..9e835d759e 100644
--- a/src/main/cpp/util/file_posix.cc
+++ b/src/main/cpp/util/file_posix.cc
@@ -169,6 +169,18 @@ IPipe* CreatePipe() {
 }
 #endif  // __CYGWIN__
 
+pair<string, string> SplitPath(const string &path) {
+  size_t pos = path.rfind('/');
+
+  // Handle the case with no '/' in 'path'.
+  if (pos == string::npos) return std::make_pair("", path);
+
+  // Handle the case with a single leading '/' in 'path'.
+  if (pos == 0) return std::make_pair(string(path, 0, 1), string(path, 1));
+
+  return std::make_pair(string(path, 0, pos), string(path, pos + 1));
+}
+
 bool ReadFile(const string &filename, string *content, int max_size) {
   int fd = open(filename.c_str(), O_RDONLY);
   if (fd == -1) return false;
diff --git a/src/main/cpp/util/file_windows.cc b/src/main/cpp/util/file_windows.cc
index 29153d1812..1d00269002 100644
--- a/src/main/cpp/util/file_windows.cc
+++ b/src/main/cpp/util/file_windows.cc
@@ -21,6 +21,7 @@
 
 namespace blaze_util {
 
+using std::pair;
 using std::string;
 
 class WindowsPipe : public IPipe {
@@ -71,6 +72,56 @@ IPipe* CreatePipe() {
   return new WindowsPipe(read_handle, write_handle);
 }
 
+static bool IsRootDirectory(const string& path) {
+  // Return true if path is "/", "\", "c:/", "c:\", "\\?\c:\", or "\??\c:\".
+  //
+  // It is unclear whether the UNC prefix is just "\\?\" or is "\??\" also
+  // valid (in some cases it seems to be, though MSDN doesn't mention it).
+  return
+      // path is "/" or "\"
+      (path.size() == 1 && (path[0] == '/' || path[0] == '\\')) ||
+      // path is "c:/" or "c:\"
+      (path.size() == 3 && isalpha(path[0]) && path[1] == ':' &&
+       (path[2] == '/' || path[2] == '\\')) ||
+      // path is "\\?\c:\" or "\??\c:\"
+      (path.size() == 7 && path[0] == '\\' &&
+       (path[1] == '\\' || path[1] == '?') && path[2] == '?' &&
+       path[3] == '\\' && isalpha(path[4]) && path[5] == ':' &&
+       path[6] == '\\');
+}
+
+pair<string, string> SplitPath(const string& path) {
+  if (path.empty()) {
+    return std::make_pair("", "");
+  }
+
+  size_t pos = path.size() - 1;
+  for (auto it = path.crbegin(); it != path.crend(); ++it, --pos) {
+    if (*it == '/' || *it == '\\') {
+      if ((pos == 2 || pos == 6) && IsRootDirectory(path.substr(0, pos + 1))) {
+        // Windows path, top-level directory, e.g. "c:\foo",
+        // result is ("c:\", "foo").
+        // Or UNC path, top-level directory, e.g. "\\?\c:\foo"
+        // result is ("\\?\c:\", "foo").
+        return std::make_pair(
+            // Include the "/" or "\" in the drive specifier.
+            path.substr(0, pos + 1), path.substr(pos + 1));
+      } else {
+        // Unix path, or relative path.
+        return std::make_pair(
+            // If the only "/" is the leading one, then that shall be the first
+            // pair element, otherwise the substring up to the rightmost "/".
+            pos == 0 ? path.substr(0, 1) : path.substr(0, pos),
+            // If the rightmost "/" is the tail, then the second pair element
+            // should be empty.
+            pos == path.size() - 1 ? "" : path.substr(pos + 1));
+      }
+    }
+  }
+  // Handle the case with no '/' or '\' in `path`.
+  return std::make_pair("", path);
+}
+
 #ifdef COMPILER_MSVC
 bool ReadFile(const string& filename, string* content, int max_size) {
   // TODO(bazel-team): implement this.
diff --git a/src/test/cpp/util/BUILD b/src/test/cpp/util/BUILD
index e16f14f4ce..80e69b7267 100644
--- a/src/test/cpp/util/BUILD
+++ b/src/test/cpp/util/BUILD
@@ -21,7 +21,12 @@ cc_test(
 cc_test(
     name = "file_test",
     srcs = ["file_test.cc"] + select({
+        "//src:windows": [
+            "file_posix_test.cc",
+            "file_windows_test.cc",
+        ],
         "//src:windows_msvc": [
+            "file_windows_test.cc",
         ],
         "//conditions:default": [
             "file_posix_test.cc",
diff --git a/src/test/cpp/util/file_posix_test.cc b/src/test/cpp/util/file_posix_test.cc
index bd91343672..0acd392bf6 100644
--- a/src/test/cpp/util/file_posix_test.cc
+++ b/src/test/cpp/util/file_posix_test.cc
@@ -44,6 +44,53 @@ static bool CreateEmptyFile(const string& path) {
   return close(fd) == 0;
 }
 
+TEST(FileTest, TestDirname) {
+  // The Posix version of SplitPath (thus Dirname too, which is implemented on
+  // top of it) is not aware of Windows paths.
+  ASSERT_EQ("", Dirname(""));
+  ASSERT_EQ("/", Dirname("/"));
+  ASSERT_EQ("", Dirname("foo"));
+  ASSERT_EQ("/", Dirname("/foo"));
+  ASSERT_EQ("/foo", Dirname("/foo/"));
+  ASSERT_EQ("foo", Dirname("foo/bar"));
+  ASSERT_EQ("foo/bar", Dirname("foo/bar/baz"));
+  ASSERT_EQ("", Dirname("\\foo"));
+  ASSERT_EQ("", Dirname("\\foo\\"));
+  ASSERT_EQ("", Dirname("foo\\bar"));
+  ASSERT_EQ("", Dirname("foo\\bar\\baz"));
+  ASSERT_EQ("foo\\bar", Dirname("foo\\bar/baz\\qux"));
+  ASSERT_EQ("c:", Dirname("c:/"));
+  ASSERT_EQ("", Dirname("c:\\"));
+  ASSERT_EQ("c:", Dirname("c:/foo"));
+  ASSERT_EQ("", Dirname("c:\\foo"));
+  ASSERT_EQ("", Dirname("\\\\?\\c:\\"));
+  ASSERT_EQ("", Dirname("\\\\?\\c:\\foo"));
+}
+
+TEST(FileTest, TestBasename) {
+  // The Posix version of SplitPath (thus Basename too, which is implemented on
+  // top of it) is not aware of Windows paths.
+  ASSERT_EQ("", Basename(""));
+  ASSERT_EQ("", Basename("/"));
+  ASSERT_EQ("foo", Basename("foo"));
+  ASSERT_EQ("foo", Basename("/foo"));
+  ASSERT_EQ("", Basename("/foo/"));
+  ASSERT_EQ("bar", Basename("foo/bar"));
+  ASSERT_EQ("baz", Basename("foo/bar/baz"));
+  ASSERT_EQ("\\foo", Basename("\\foo"));
+  ASSERT_EQ("\\foo\\", Basename("\\foo\\"));
+  ASSERT_EQ("foo\\bar", Basename("foo\\bar"));
+  ASSERT_EQ("foo\\bar\\baz", Basename("foo\\bar\\baz"));
+  ASSERT_EQ("baz\\qux", Basename("foo\\bar/baz\\qux"));
+  ASSERT_EQ("qux", Basename("qux"));
+  ASSERT_EQ("", Basename("c:/"));
+  ASSERT_EQ("c:\\", Basename("c:\\"));
+  ASSERT_EQ("foo", Basename("c:/foo"));
+  ASSERT_EQ("c:\\foo", Basename("c:\\foo"));
+  ASSERT_EQ("\\\\?\\c:\\", Basename("\\\\?\\c:\\"));
+  ASSERT_EQ("\\\\?\\c:\\foo", Basename("\\\\?\\c:\\foo"));
+}
+
 TEST(FileTest, JoinPath) {
   std::string path = JoinPath("", "");
   ASSERT_EQ("", path);
diff --git a/src/test/cpp/util/file_windows_test.cc b/src/test/cpp/util/file_windows_test.cc
new file mode 100644
index 0000000000..85cc7a491e
--- /dev/null
+++ b/src/test/cpp/util/file_windows_test.cc
@@ -0,0 +1,68 @@
+// Copyright 2016 The Bazel Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//    http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+#include <string.h>
+
+#include "src/main/cpp/util/file.h"
+#include "src/main/cpp/util/file_platform.h"
+#include "gtest/gtest.h"
+
+#if !defined(COMPILER_MSVC) && !defined(__CYGWIN__)
+#error("This test should only be run on Windows")
+#endif  // !defined(COMPILER_MSVC) && !defined(__CYGWIN__)
+
+namespace blaze_util {
+
+TEST(FileTest, TestDirname) {
+  ASSERT_EQ("", Dirname(""));
+  ASSERT_EQ("/", Dirname("/"));
+  ASSERT_EQ("", Dirname("foo"));
+  ASSERT_EQ("/", Dirname("/foo"));
+  ASSERT_EQ("/foo", Dirname("/foo/"));
+  ASSERT_EQ("foo", Dirname("foo/bar"));
+  ASSERT_EQ("foo/bar", Dirname("foo/bar/baz"));
+  ASSERT_EQ("\\", Dirname("\\foo"));
+  ASSERT_EQ("\\foo", Dirname("\\foo\\"));
+  ASSERT_EQ("foo", Dirname("foo\\bar"));
+  ASSERT_EQ("foo\\bar", Dirname("foo\\bar\\baz"));
+  ASSERT_EQ("foo\\bar/baz", Dirname("foo\\bar/baz\\qux"));
+  ASSERT_EQ("c:/", Dirname("c:/"));
+  ASSERT_EQ("c:\\", Dirname("c:\\"));
+  ASSERT_EQ("c:/", Dirname("c:/foo"));
+  ASSERT_EQ("c:\\", Dirname("c:\\foo"));
+  ASSERT_EQ("\\\\?\\c:\\", Dirname("\\\\?\\c:\\"));
+  ASSERT_EQ("\\\\?\\c:\\", Dirname("\\\\?\\c:\\foo"));
+}
+
+TEST(FileTest, TestBasename) {
+  ASSERT_EQ("", Basename(""));
+  ASSERT_EQ("", Basename("/"));
+  ASSERT_EQ("foo", Basename("foo"));
+  ASSERT_EQ("foo", Basename("/foo"));
+  ASSERT_EQ("", Basename("/foo/"));
+  ASSERT_EQ("bar", Basename("foo/bar"));
+  ASSERT_EQ("baz", Basename("foo/bar/baz"));
+  ASSERT_EQ("foo", Basename("\\foo"));
+  ASSERT_EQ("", Basename("\\foo\\"));
+  ASSERT_EQ("bar", Basename("foo\\bar"));
+  ASSERT_EQ("baz", Basename("foo\\bar\\baz"));
+  ASSERT_EQ("qux", Basename("foo\\bar/baz\\qux"));
+  ASSERT_EQ("", Basename("c:/"));
+  ASSERT_EQ("", Basename("c:\\"));
+  ASSERT_EQ("foo", Basename("c:/foo"));
+  ASSERT_EQ("foo", Basename("c:\\foo"));
+  ASSERT_EQ("", Basename("\\\\?\\c:\\"));
+  ASSERT_EQ("foo", Basename("\\\\?\\c:\\foo"));
+}
+
+}  // namespace blaze_util