swarm/api: improve FUSE build constraints, logging and APIs (#3818)

* swarm/api: fix build/tests on unsupported platforms

Skip FUSE tests if FUSE is unavailable and change build constraints so
the 'lesser' platforms aren't mentioned explicitly. The test are
compiled on all platforms to prevent regressions in _fallback.go

Also gofmt -w -s because why not.

* internal/web3ext: fix swarmfs wrappers

Remove inputFormatter specifications so users get an error
when passing the wrong number of arguments.

* swarm/api: improve FUSE-related logging and APIs

The API now returns JSON objects instead of strings.
Log messages for invalid arguments are removed.

1 files changed, 50 insertions, 0 deletions

diff --git a/swarm/api/swarmfs_fallback.go b/swarm/api/swarmfs_fallback.go
new file mode 100644
index 000000000..c6ac07d14
--- /dev/null
+++ b/swarm/api/swarmfs_fallback.go
@@ -0,0 +1,50 @@
+// Copyright 2017 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+// +build !linux,!darwin,!freebsd
+
+package api
+
+import (
+	"errors"
+)
+
+var errNoFUSE = errors.New("FUSE is not supported on this platform")
+
+func isFUSEUnsupportedError(err error) bool {
+	return err == errNoFUSE
+}
+
+type MountInfo struct {
+	MountPoint   string
+	ManifestHash string
+}
+
+func (self *SwarmFS) Mount(mhash, mountpoint string) (*MountInfo, error) {
+	return nil, errNoFUSE
+}
+
+func (self *SwarmFS) Unmount(mountpoint string) (bool, error) {
+	return false, errNoFUSE
+}
+
+func (self *SwarmFS) Listmounts() ([]*MountInfo, error) {
+	return nil, errNoFUSE
+}
+
+func (self *SwarmFS) Stop() error {
+	return nil
+}