Bazel client: abstract away mtime handling

Create an IFileMtime class and platform-specific
implementations to deal with mtime handling.

Since epochs and time granularity vary from
platform to platform, and we only care about
setting a file's/directory's mtime to the current
time or to a future time plus querying whether
something is in the future, we can easily create
an interface for these operations and that's
exactly what IFileMtime is.

Implement PosixFileMtime and WindowsFileMtime.

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

--
PiperOrigin-RevId: 144956966
MOS_MIGRATED_REVID=144956966

1 files changed, 24 insertions, 9 deletions

diff --git a/src/main/cpp/util/file_platform.h b/src/main/cpp/util/file_platform.h
index 6c2e20500c..600820ba0c 100644
--- a/src/main/cpp/util/file_platform.h
+++ b/src/main/cpp/util/file_platform.h
@@ -26,6 +26,30 @@ class IPipe;
 
 IPipe* CreatePipe();
 
+// Class to query/manipulate the last modification time (mtime) of files.
+class IFileMtime {
+ public:
+  virtual ~IFileMtime() {}
+
+  // Queries the mtime of `path` to see whether it's in the distant future.
+  // Returns true if querying succeeded and stores the result in `result`.
+  // Returns false if querying failed.
+  virtual bool GetIfInDistantFuture(const std::string &path, bool *result) = 0;
+
+  // Sets the mtime of file under `path` to the current time.
+  // Returns true if the mtime was changed successfully.
+  virtual bool SetToNow(const std::string &path) = 0;
+
+  // Sets the mtime of file under `path` to the distant future.
+  // "Distant future" should be on the order of some years into the future, like
+  // a decade.
+  // Returns true if the mtime was changed successfully.
+  virtual bool SetToDistantFuture(const std::string &path) = 0;
+};
+
+// Creates a platform-specific implementation of `IFileMtime`.
+IFileMtime *CreateFileMtime();
+
 // Split a path to dirname and basename parts.
 std::pair<std::string, std::string> SplitPath(const std::string &path);
 
@@ -80,15 +104,6 @@ bool IsAbsolute(const std::string &path);
 // pdie() if syncing fails.
 void SyncFile(const std::string& path);
 
-// Returns the last modification time of `path` in milliseconds since the Epoch.
-// Returns -1 upon failure.
-time_t GetMtimeMillisec(const std::string& path);
-
-// Sets the last modification time of `path` to the given value.
-// `mtime` must be milliseconds since the Epoch.
-// Returns true upon success.
-bool SetMtimeMillisec(const std::string& path, time_t mtime);
-
 // mkdir -p path. All newly created directories use the given mode.
 // `mode` should be an octal permission mask, e.g. 0755.
 // Returns false on failure, sets errno.