Switch over to the google3 unix_file File*.
I also moved macros.h to base/macros.h to ease google3 porting, at
the expense of a larger than necessary change. (I learned my lesson,
though, and didn't make the equivalent base/logging.h change.)
I'm not sure whether we want to keep the unix_file MappedFile given
our existing MemMap, but it's easier to bring it over and then remove
it (and possibly revert the removal) than to bring it over later.
Change-Id: Id50a66faa5ab17b9bc936cc9043dbc26f791f0ca
diff --git a/src/base/unix_file/README b/src/base/unix_file/README
new file mode 100644
index 0000000..e9aec22
--- /dev/null
+++ b/src/base/unix_file/README
@@ -0,0 +1,15 @@
+A simple C++ wrapper for Unix file I/O.
+
+This is intended to be lightweight and easy to use, similar to Java's
+RandomAccessFile and related classes. The usual C++ idioms of RAII and "you
+don't pay for what you don't use" apply.
+
+In particular, the basic RandomAccessFile interface is kept small and simple so
+it's trivial to add new implementations.
+
+This code will not log, because it can't know whether that's appropriate in
+your application.
+
+This code will, in general, return -errno on failure. If an operation consisted
+of multiple sub-operations, it will return the errno corresponding to the most
+relevant operation.