Bazel client: implement directory tree walking

This change:

- merges the //src/{main,test}/cpp:file and
//src/{main,test}/cpp:file_platform libraries
because "file" and "file_platform" need each other
and this makes logical sense anyway

- implements a function in file_<platform> to run
a custom function on every child of a directory

- implements a function in file.cc to recursively
traverse a directory tree, based on the previosly
mentioned function

- removes the corresponding logic from the Bazel
client to make it more portable

--
MOS_MIGRATED_REVID=139309562

1 files changed, 21 insertions, 0 deletions

diff --git a/src/main/cpp/util/file.h b/src/main/cpp/util/file.h
index 238ccf0d9f..dfa08ad629 100644
--- a/src/main/cpp/util/file.h
+++ b/src/main/cpp/util/file.h
@@ -15,6 +15,7 @@
 #define BAZEL_SRC_MAIN_CPP_UTIL_FILE_H_
 
 #include <string>
+#include <vector>
 
 namespace blaze_util {
 
@@ -29,6 +30,26 @@ std::string Basename(const std::string &path);
 
 std::string JoinPath(const std::string &path1, const std::string &path2);
 
+// Lists all files in `path` and all of its subdirectories.
+//
+// Does not follow symlinks / junctions.
+//
+// Populates `result` with the full paths of the files. Every entry will have
+// `path` as its prefix. If `path` is a file, `result` contains just this file.
+void GetAllFilesUnder(const std::string &path,
+                      std::vector<std::string> *result);
+
+class DirectoryEntryConsumer;
+
+// Visible for testing only.
+typedef void (*_ForEachDirectoryEntry)(const std::string &path,
+                                       DirectoryEntryConsumer *consume);
+
+// Visible for testing only.
+void _GetAllFilesUnder(const std::string &path,
+                       std::vector<std::string> *result,
+                       _ForEachDirectoryEntry walk_entries);
+
 }  // namespace blaze_util
 
 #endif  // BAZEL_SRC_MAIN_CPP_UTIL_FILE_H_