swarm: plan bee for content storage and distribution on web3

This change imports the Swarm protocol codebase. Compared to the 'swarm'
branch, a few mostly cosmetic changes had to be made:

* The various redundant log message prefixes are gone.
* All files now have LGPLv3 license headers.
* Minor code changes were needed to please go vet and make the tests
  pass on Windows.
* Further changes were required to adapt to the go-ethereum develop
  branch and its new Go APIs.

Some code has not (yet) been brought over:

* swarm/cmd/bzzhash: will reappear as cmd/bzzhash later
* swarm/cmd/bzzup.sh: will be reimplemented in cmd/bzzup
* swarm/cmd/makegenesis: will reappear somehow
* swarm/examples/album: will move to a separate repository
* swarm/examples/filemanager: ditto
* swarm/examples/files: will not be merged
* swarm/test/*: will not be merged
* swarm/services/swear: will reappear as contracts/swear when needed

swarm/api/storage.go

@@ -0,0 +1,70 @@
+// Copyright 2016 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/>.
+
+package api
+
+type Response struct {
+	MimeType string
+	Status   int
+	Size     int64
+	// Content  []byte
+	Content string
+}
+
+// implements a service
+type Storage struct {
+	api *Api
+}
+
+func NewStorage(api *Api) *Storage {
+	return &Storage{api}
+}
+
+// Put uploads the content to the swarm with a simple manifest speficying
+// its content type
+func (self *Storage) Put(content, contentType string) (string, error) {
+	return self.api.Put(content, contentType)
+}
+
+// Get retrieves the content from bzzpath and reads the response in full
+// It returns the Response object, which serialises containing the
+// response body as the value of the Content field
+// NOTE: if error is non-nil, sResponse may still have partial content
+// the actual size of which is given in len(resp.Content), while the expected
+// size is resp.Size
+func (self *Storage) Get(bzzpath string) (*Response, error) {
+	reader, mimeType, status, err := self.api.Get(bzzpath, true)
+	if err != nil {
+		return nil, err
+	}
+	quitC := make(chan bool)
+	expsize, err := reader.Size(quitC)
+	if err != nil {
+		return nil, err
+	}
+	body := make([]byte, expsize)
+	size, err := reader.Read(body)
+	if int64(size) == expsize {
+		err = nil
+	}
+	return &Response{mimeType, status, expsize, string(body[:size])}, err
+}
+
+// Modify(rootHash, path, contentHash, contentType) takes th e manifest trie rooted in rootHash,
+// and merge on  to it. creating an entry w conentType (mime)
+func (self *Storage) Modify(rootHash, path, contentHash, contentType string) (newRootHash string, err error) {
+	return self.api.Modify(rootHash+"/"+path, contentHash, contentType, true)
+}