tree 05b10c5bf52e457d20c93bf04ce9d2fe8fb205c4
parent 3265b317b39edea86b5351029092b7728ca8461b
author Kelvin Zhang <zhangkelvin@google.com> 1603828233 -0400
committer Kelvin Zhang <zhangkelvin@google.com> 1609804271 -0500

Use string_view for pref interface to reduce copy

If you pass in a static string literal like "Hello World!", then with
parameter type of const string& you need to construct a new string
object, requiring a copy. It will also require a copy if your data is in
another container, for example std::vector<char> . In update_engine, we
store manifest bytes in std::vector, and sometimes we want to save that
manifest to disk. This CL can help us reduce copy of the manifest(up to
2MB).

Test: treehugger
Change-Id: I70feb4c0673c174fd47f02c4bd41994f74cda743