From: Tor Arne Vestbø <tor.arne.vestbo@qt.io>
Date: Thu, 15 Jun 2017 12:49:28 +0000 (+0200)
Subject: Add comment about why SLOPPY_INCLUDE_FILE_[CM]TIME compares using >=t
X-Git-Tag: v3.3.5~26
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=cf4c4bc053740aa4d9526b1efef65245f9852ed2;p=thirdparty%2Fccache.git

Add comment about why SLOPPY_INCLUDE_FILE_[CM]TIME compares using >=t
---

diff --git a/ccache.c b/ccache.c
index 01e18218d..4d7d8052c 100644
--- a/ccache.c
+++ b/ccache.c
@@ -560,12 +560,16 @@ remember_include_file(char *path, struct mdfour *cpp_hash, bool system)
 		}
 	}
 
+	// The comparison using >= is intentional, due to a possible race
+	// between starting compilation and writing the include file.
+	// See https://github.com/ccache/ccache/blob/master/MANUAL.txt
 	if (!(conf->sloppiness & SLOPPY_INCLUDE_FILE_MTIME)
 	    && st.st_mtime >= time_of_compilation) {
 		cc_log("Include file %s too new", path);
 		goto failure;
 	}
 
+	// The same >= logic as above applies to the change time of the file.
 	if (!(conf->sloppiness & SLOPPY_INCLUDE_FILE_CTIME)
 	    && st.st_ctime >= time_of_compilation) {
 		cc_log("Include file %s ctime too new", path);