On Windows, we can't "os.rename" over an existing file. Closes #104.

3 files changed, 32 insertions, 1 deletions

diff --git a/src/luarocks/fs/unix.lua b/src/luarocks/fs/unix.lua
index e0d40970..cfd20c70 100644
--- a/src/luarocks/fs/unix.lua
+++ b/src/luarocks/fs/unix.lua
@@ -93,3 +93,17 @@ end
 function copy_binary(filename, dest) 
    return fs.copy(filename, dest, "0755")
 end
+
+--- Move a file on top of the other.
+-- The new file ceases to exist under its original name,
+-- and takes over the name of the old file.
+-- On Unix this is done through a single rename operation.
+-- @param old_file The name of the original file,
+-- which will be the new name of new_file.
+-- @param new_file The name of the new file,
+-- which will replace old_file.
+-- @return boolean or (nil, string): True if succeeded, or nil and
+-- an error message.
+function replace_file(old_file, new_file)
+   return os.rename(new_file, old_file)
+end
diff --git a/src/luarocks/fs/win32.lua b/src/luarocks/fs/win32.lua
index cbf5fc60..2c78d9b6 100644
--- a/src/luarocks/fs/win32.lua
+++ b/src/luarocks/fs/win32.lua
@@ -112,3 +112,20 @@ end
 function get_permissions(filename)
    return ""
 end
+
+--- Move a file on top of the other.
+-- The new file ceases to exist under its original name,
+-- and takes over the name of the old file.
+-- On Windows this is done by removing the original file and
+-- renaming the new file to its original name.
+-- @param old_file The name of the original file,
+-- which will be the new name of new_file.
+-- @param new_file The name of the new file,
+-- which will replace old_file.
+-- @return boolean or (nil, string): True if succeeded, or nil and
+-- an error message.
+function replace_file(old_file, new_file)
+   os.remove(old_file)
+   return os.rename(new_file, old_file)
+end
+
diff --git a/src/luarocks/manif.lua b/src/luarocks/manif.lua
index 2c745f0b..65a6beba 100644
--- a/src/luarocks/manif.lua
+++ b/src/luarocks/manif.lua
@@ -33,7 +33,7 @@ local function save_table(where, name, tbl)
    local filename = dir.path(where, name)
    local ok, err = persist.save_from_table(filename..".tmp", tbl)
    if ok then
-      ok, err = os.rename(filename..".tmp", filename)
+      ok, err = fs.replace_file(filename, filename..".tmp")
    end
    return ok, err
 end