Bazel client: split CanAccess to specific methods

The new methods (CanReadFile, CanExecuteFile,
CanAccessDirectory) are a lot easier to implement
on Windows than a generic CanAccess. On POSIX
these methods are just a wrapper around the now
static-visible CanAccess().

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

--
PiperOrigin-RevId: 144176710
MOS_MIGRATED_REVID=144176710

3 files changed, 39 insertions, 10 deletions

diff --git a/src/main/cpp/util/file_platform.h b/src/main/cpp/util/file_platform.h
index 91fc086627..2c07c3731d 100644
--- a/src/main/cpp/util/file_platform.h
+++ b/src/main/cpp/util/file_platform.h
@@ -54,12 +54,18 @@ bool PathExists(const std::string& path);
 // This is a wrapper around realpath(3).
 std::string MakeCanonical(const char *path);
 
-// Returns true if the path exists and can be accessed to read/write as desired.
-//
-// If `exec` is true and the path refers to a file, it means the file must be
-// executable; if the path is a directory, it means the directory must be
-// openable.
-bool CanAccess(const std::string& path, bool read, bool write, bool exec);
+// Returns true if `path` exists, is a file or symlink to one, and is readable.
+// Follows symlinks.
+bool CanReadFile(const std::string &path);
+
+// Returns true if `path` exists, is a file or symlink to one, and is writable.
+// Follows symlinks.
+bool CanExecuteFile(const std::string &path);
+
+// Returns true if `path` exists, is a directory or symlink/junction to one, and
+// is both readable and writable.
+// Follows symlinks/junctions.
+bool CanAccessDirectory(const std::string &path);
 
 // Returns true if `path` refers to a directory or a symlink/junction to one.
 bool IsDirectory(const std::string& path);
diff --git a/src/main/cpp/util/file_posix.cc b/src/main/cpp/util/file_posix.cc
index 466bae499d..c1a313a1f3 100644
--- a/src/main/cpp/util/file_posix.cc
+++ b/src/main/cpp/util/file_posix.cc
@@ -234,7 +234,7 @@ string MakeCanonical(const char *path) {
   }
 }
 
-bool CanAccess(const string& path, bool read, bool write, bool exec) {
+static bool CanAccess(const string &path, bool read, bool write, bool exec) {
   int mode = 0;
   if (read) {
     mode |= R_OK;
@@ -248,6 +248,18 @@ bool CanAccess(const string& path, bool read, bool write, bool exec) {
   return access(path.c_str(), mode) == 0;
 }
 
+bool CanReadFile(const std::string &path) {
+  return !IsDirectory(path) && CanAccess(path, true, false, false);
+}
+
+bool CanExecuteFile(const std::string &path) {
+  return !IsDirectory(path) && CanAccess(path, false, false, true);
+}
+
+bool CanAccessDirectory(const std::string &path) {
+  return IsDirectory(path) && CanAccess(path, true, true, true);
+}
+
 #ifndef __CYGWIN__
 bool IsDirectory(const string& path) {
   struct stat buf;
diff --git a/src/main/cpp/util/file_windows.cc b/src/main/cpp/util/file_windows.cc
index 3a5b5ac8e4..4293d5ead7 100644
--- a/src/main/cpp/util/file_windows.cc
+++ b/src/main/cpp/util/file_windows.cc
@@ -548,12 +548,23 @@ bool PathExists(const string& path) {
 }
 
 #ifdef COMPILER_MSVC
-bool CanAccess(const string& path, bool read, bool write, bool exec) {
+bool CanReadFile(const std::string& path) {
   // TODO(bazel-team): implement this.
-  pdie(255, "blaze_util::CanAccess is not implemented on Windows");
+  pdie(255, "not implemented on Windows");
+  return false;
+}
+
+bool CanExecuteFile(const std::string& path) {
+  // TODO(bazel-team): implement this.
+  pdie(255, "not implemented on Windows");
+  return false;
+}
+
+bool CanAccessDirectory(const std::string& path) {
+  // TODO(bazel-team): implement this.
+  pdie(255, "not implemented on Windows");
   return false;
 }
-#else  // not COMPILER_MSVC
 #endif  // COMPILER_MSVC
 
 static bool IsDirectoryW(const wstring& path) {