From 05a529a171ddbcc3ebded4284021912db59714b1 Mon Sep 17 00:00:00 2001
From: Gordon Hecker <gh@emlix.com>
Date: Fri, 23 Oct 2009 11:22:29 +0200
Subject: [PATCH] Implement cache and transport flag for internal use:
 try_hardlink transport.push_file() tries to optimize by creating a hardlink
 before falling back to copying if that fails.

Signed-off-by: Gordon Hecker <gh@emlix.com>
---
 generic/cache.lua     | 10 ++++++----
 generic/transport.lua | 22 ++++++++++++++++++----
 2 files changed, 24 insertions(+), 8 deletions(-)

diff --git a/generic/cache.lua b/generic/cache.lua
index c5caf81..5e11357 100644
--- a/generic/cache.lua
+++ b/generic/cache.lua
@@ -309,8 +309,8 @@ function push_file(cache, sourcefile, server, location, flags)
 		-- cache is enabled:
 		-- push the file from source to cache and from cache to
 		-- destination
-		rc, re = transport.push_file(sourcefile, ce.cache_url, location,
-									nil)
+		rc, re = transport.push_file(sourcefile, ce.cache_url,
+					location, nil, flags.try_hardlink)
 		if not rc then
 			return false, e:cat(re)
 		end
@@ -322,7 +322,8 @@ function push_file(cache, sourcefile, server, location, flags)
 		-- cache is disabled
 		-- push the file from source to destination immediately
 		rc, re = transport.push_file(sourcefile, ce.remote_url,
-					location, ce.flags.push_permissions)
+					location, ce.flags.push_permissions,
+					flags.try_hardlink)
 		if not rc then
 			return false, e:cat(re)
 		end
@@ -355,7 +356,8 @@ function writeback(cache, server, location, flags)
 	end
 	local sourcefile = string.format("/%s/%s", ceurl.path, location)
 	rc, re = transport.push_file(sourcefile, ce.remote_url, location,
-						ce.flags.push_permissions)
+						ce.flags.push_permissions,
+						flags.try_hardlink)
 	if not rc then
 		return false, e:cat(re)
 	end
diff --git a/generic/transport.lua b/generic/transport.lua
index a2258c1..191f43b 100644
--- a/generic/transport.lua
+++ b/generic/transport.lua
@@ -205,9 +205,10 @@ end
 -- @param location location relative to the server url
 -- @param push_permissions string: permissions to use on the destination
 --        side. Works with rsync+ssh only.
+-- @param try_hardlink bool: optimize by trying to hardlink instead of copying
 -- @return true on success, false on error
 -- @return nil, an error string on error
-function push_file(sourcefile, durl, location, push_permissions)
+function push_file(sourcefile, durl, location, push_permissions, try_hardlink)
 	e2lib.log(4, string.format("%s: %s %s %s %s", "transport.push_file()",
 		sourcefile, durl, location, tostring(push_permissions)))
 	local rc, e
@@ -240,9 +241,22 @@ function push_file(sourcefile, durl, location, push_permissions)
 		end
 		local args = string.format("%s '%s' '%s/%s'", rsync_perm,
 						sourcefile, destdir, destname)
-		rc, re = e2lib.rsync(args)
-		if not rc then
-			return false, re
+		local done = false
+		if (not push_permissions) and try_hardlink then
+			local dst = string.format("%s/%s", destdir, destname)
+			rc, re = e2lib.ln(sourcefile, dst, "--force")
+			if rc then
+				done = true
+			else
+				e2lib.logf(4, "Creating hardlink failed. "..
+						"Falling back to copying.")
+			end
+		end
+		if not done then
+			rc, re = e2lib.rsync(args)
+			if not rc then
+				return false, re
+			end
 		end
 	elseif u.transport == "rsync+ssh" then
 		local destdir = string.format("/%s", e2lib.dirname(u.path))
-- 
2.39.5