Introduce a Truncate() function that works on POSIX and Windows.

Hopefully fixes the build on Windows.

1 files changed, 20 insertions, 0 deletions

diff --git a/src/util.cc b/src/util.cc
index 91e8fad..e78dda3 100644
--- a/src/util.cc
+++ b/src/util.cc
@@ -29,6 +29,7 @@
 #include <sys/types.h>
 
 #ifndef _WIN32
+#include <unistd.h>
 #include <sys/time.h>
 #endif
 
@@ -354,3 +355,22 @@ string ElideMiddle(const string& str, size_t width) {
   }
   return result;
 }
+
+bool Truncate(const string& path, size_t size, string* err) {
+#ifdef _WIN32
+  int fh;
+  fh = _sopen(kTestFilename, _O_RDWR | _O_CREAT, _SH_DENYNO,
+              _S_IREAD | _S_IWRITE);
+  int success = _chsize(fh, size);
+  _close(fh);
+#else
+  int success = truncate(path.c_str(), size);
+#endif
+  // Both truncate() and _chsize() return 0 on success and set errno and return
+  // -1 on failure.
+  if (success < 0) {
+    *err = strerror(errno);
+    return false;
+  }
+  return true;
+}