From f25a603708aaadbb0dae0e3dce2f3067d48628d5 Mon Sep 17 00:00:00 2001
From: Jacob Dufault <jacobdufault@gmail.com>
Date: Thu, 20 Apr 2017 09:47:24 -0700
Subject: [PATCH] Implement GetLastModificationTime for linux

---
 src/platform_linux.cc | 25 ++++++++++++++++++++++---
 1 file changed, 22 insertions(+), 3 deletions(-)

diff --git a/src/platform_linux.cc b/src/platform_linux.cc
index d9969e45..04289b53 100644
--- a/src/platform_linux.cc
+++ b/src/platform_linux.cc
@@ -21,14 +21,13 @@
 
 #include <dirent.h>
 #include <sys/types.h> // required for stat.h
-#include <sys/stat.h> // no clue why required -- man pages say so
+#include <sys/stat.h>
+
 
 #include <fcntl.h>    /* For O_* constants */
 #include <sys/stat.h> /* For mode constants */
 #include <semaphore.h>
 #include <sys/mman.h>
-#include <sys/stat.h> /* For mode constants */
-#include <fcntl.h>    /* For O_* constants */
 
 #ifndef __APPLE__
 #include <sys/prctl.h>
@@ -163,6 +162,26 @@ void SetCurrentThreadName(const std::string& thread_name) {
 #endif
 }
 
+int64_t GetLastModificationTime(const std::string& absolute_path) {
+  struct stat buf;
+  if (stat(absolute_path.c_str(), &buf) != 0) {
+    switch (errno) {
+      case ENOENT:
+        std::cerr << "GetLastModificationTime: unable to find file " << absolute_path << std::endl;
+        break;
+      case EINVAL:
+        std::cerr << "GetLastModificationTime: invalid param to _stat for file file " << absolute_path << std::endl;
+        break;
+      default:
+        std::cerr << "GetLastModificationTime: unhandled for " << absolute_path << std::endl;
+        exit(1);
+        break;
+    }
+  }
+
+  return buf.st_mtime;
+}
+
 std::vector<std::string> GetPlatformClangArguments() {
   // TODO: use install config variable for path?
   return {