tree 2c835ec1a5c43ec4b0a483e72114993cd305bf8c
parent 782c6b3cc7241a4f2a5dd0614d01afbac3ae614e
author Heschi Kreinick <heschi@google.com> 1591644084 -0400
committer Heschi Kreinick <heschi@google.com> 1591913519 +0000

internal/lsp: read files eagerly

We use file identities pervasively throughout gopls. Prior to this
change, the identity is the modification date of an unopened file, or
the hash of an opened file. That means that opening a file changes its
identity, which causes unnecessary churn in the cache.

Unfortunately, there isn't an easy way to fix this. Changing the
cache key to something else, such as the modification time, means that
we won't unify cache entries if a change is made and then undone. The
approach here is to read files eagerly in GetFile, so that we know their
hashes immediately. That resolves the churn, but means that we do a ton
of file IO at startup.

Incidental changes:

Remove the FileSystem interface; there was only one implementation and
it added a fair amount of cruft. We have many other places that assume
os.Stat and such work.

Add direct accessors to FileHandle for URI, Kind, and Version. Most uses
of (FileHandle).Identity were for stuff that we derive solely from the
URI, and this helped me disentangle them. It is a *ton* of churn,
though. I can revert it if you want.

Change-Id: Ia2133bc527f71daf81c9d674951726a232ca5bc9
Reviewed-on: https://go-review.googlesource.com/c/tools/+/237037
Run-TryBot: Heschi Kreinick <heschi@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rebecca Stambler <rstambler@golang.org>