idmap2: introduce improved Result class
Add a new version of the Result class that functions like the old
Result, but in case of an error, also encodes a string detailing the
error. This will allow us to write the following type of code:
Result<Foo> CreateFoo() {
if (...) {
return Error("errno=%d", errno());
}
return Foo(...);
}
auto foo = CreateFoo();
if (!foo) {
std::cerr << "error: " << foo.GetErrorMessage() << std::endl;
abort();
}
std::cout << "foo=" << *foo << std::endl;
This commit only adds the new Result class. A later change will replace
uses of the old version.
Test: make idmap2_tests
Change-Id: I674d8a06866402adedf85f8514400f25840d5eda
diff --git a/cmds/idmap2/static-checks.sh b/cmds/idmap2/static-checks.sh
index ad9830b..5740710 100755
--- a/cmds/idmap2/static-checks.sh
+++ b/cmds/idmap2/static-checks.sh
@@ -73,6 +73,7 @@
local output="$($cpplint --quiet $cpp_files 2>&1 >/dev/null | grep -v \
-e 'Found C system header after C++ system header.' \
-e 'Unknown NOLINT error category: misc-non-private-member-variables-in-classes' \
+ -e 'Unknown NOLINT error category: performance-unnecessary-copy-initialization' \
)"
if [[ "$output" ]]; then
echo "$output"