Fix Resource output in multihost setups

In Hugo 0.46 we made the output of what you get from resources.Get and similar static, i.e. language agnostic. This makes total sense, as it is wasteful and time-consuming to do SASS/SCSS/PostCSS processing for lots of languages when the output is lots of duplicates with different filenames.

But since we now output the result once only, this had a negative side effect for multihost setups: We publish the resource once only to the root folder (i.e. not to the language "domain folder").

This commit removes the language code from the processed image keys. This creates less duplication in the file cache, but it means that you should do a `hugo --gc` to clean up stale files.

Fixes #5058

2 files changed, 96 insertions, 0 deletions

diff --git a/common/hugio/readers.go b/common/hugio/readers.go
new file mode 100644
index 000000000..ba55e2d08
--- /dev/null
+++ b/common/hugio/readers.go
@@ -0,0 +1,53 @@
+// Copyright 2018 The Hugo Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package hugio
+
+import (
+	"io"
+	"strings"
+)
+
+// ReadSeeker wraps io.Reader and io.Seeker.
+type ReadSeeker interface {
+	io.Reader
+	io.Seeker
+}
+
+// ReadSeekCloser is implemented by afero.File. We use this as the common type for
+// content in Resource objects, even for strings.
+type ReadSeekCloser interface {
+	ReadSeeker
+	io.Closer
+}
+
+// ReadSeekerNoOpCloser implements ReadSeekCloser by doing nothing in Close.
+type ReadSeekerNoOpCloser struct {
+	ReadSeeker
+}
+
+// Close does nothing.
+func (r ReadSeekerNoOpCloser) Close() error {
+	return nil
+}
+
+// NewReadSeekerNoOpCloser creates a new ReadSeekerNoOpCloser with the given ReadSeeker.
+func NewReadSeekerNoOpCloser(r ReadSeeker) ReadSeekerNoOpCloser {
+	return ReadSeekerNoOpCloser{r}
+}
+
+// NewReadSeekerNoOpCloserFromString uses strings.NewReader to create a new ReadSeekerNoOpCloser
+// from the given string.
+func NewReadSeekerNoOpCloserFromString(content string) ReadSeekerNoOpCloser {
+	return ReadSeekerNoOpCloser{strings.NewReader(content)}
+}
diff --git a/common/hugio/writers.go b/common/hugio/writers.go
new file mode 100644
index 000000000..2766146e1
--- /dev/null
+++ b/common/hugio/writers.go
@@ -0,0 +1,43 @@
+// Copyright 2018 The Hugo Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package hugio
+
+import (
+	"io"
+)
+
+type multiWriteCloser struct {
+	io.Writer
+	closers []io.WriteCloser
+}
+
+func (m multiWriteCloser) Close() error {
+	var err error
+	for _, c := range m.closers {
+		if closeErr := c.Close(); err != nil {
+			err = closeErr
+		}
+	}
+	return err
+}
+
+// NewMultiWriteCloser creates a new io.WriteCloser that duplicates its writes to all the
+// provided writers.
+func NewMultiWriteCloser(writeClosers ...io.WriteCloser) io.WriteCloser {
+	writers := make([]io.Writer, len(writeClosers))
+	for i, w := range writeClosers {
+		writers[i] = w
+	}
+	return multiWriteCloser{Writer: io.MultiWriter(writers...), closers: writeClosers}
+}