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

1 files changed, 191 insertions, 0 deletions

diff --git a/swarm/api/api.go b/swarm/api/api.go
new file mode 100644
index 000000000..673cff350
--- /dev/null
+++ b/swarm/api/api.go
@@ -0,0 +1,191 @@
+// 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
+
+import (
+	"fmt"
+	"io"
+	"regexp"
+	"strings"
+	"sync"
+
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/logger"
+	"github.com/ethereum/go-ethereum/logger/glog"
+	"github.com/ethereum/go-ethereum/swarm/storage"
+)
+
+var (
+	hashMatcher      = regexp.MustCompile("^[0-9A-Fa-f]{64}")
+	slashes          = regexp.MustCompile("/+")
+	domainAndVersion = regexp.MustCompile("[@:;,]+")
+)
+
+type Resolver interface {
+	Resolve(string) (common.Hash, error)
+}
+
+/*
+Api implements webserver/file system related content storage and retrieval
+on top of the dpa
+it is the public interface of the dpa which is included in the ethereum stack
+*/
+type Api struct {
+	dpa *storage.DPA
+	dns Resolver
+}
+
+//the api constructor initialises
+func NewApi(dpa *storage.DPA, dns Resolver) (self *Api) {
+	self = &Api{
+		dpa: dpa,
+		dns: dns,
+	}
+	return
+}
+
+// DPA reader API
+func (self *Api) Retrieve(key storage.Key) storage.LazySectionReader {
+	return self.dpa.Retrieve(key)
+}
+
+func (self *Api) Store(data io.Reader, size int64, wg *sync.WaitGroup) (key storage.Key, err error) {
+	return self.dpa.Store(data, size, wg, nil)
+}
+
+type ErrResolve error
+
+// DNS Resolver
+func (self *Api) Resolve(hostPort string, nameresolver bool) (storage.Key, error) {
+	if hashMatcher.MatchString(hostPort) || self.dns == nil {
+		glog.V(logger.Detail).Infof("host is a contentHash: '%v'", hostPort)
+		return storage.Key(common.Hex2Bytes(hostPort)), nil
+	}
+	if !nameresolver {
+		return nil, fmt.Errorf("'%s' is not a content hash value.", hostPort)
+	}
+	contentHash, err := self.dns.Resolve(hostPort)
+	if err != nil {
+		err = ErrResolve(err)
+		glog.V(logger.Warn).Infof("DNS error : %v", err)
+	}
+	glog.V(logger.Detail).Infof("host lookup: %v -> %v", err)
+	return contentHash[:], err
+}
+
+func parse(uri string) (hostPort, path string) {
+	parts := slashes.Split(uri, 3)
+	var i int
+	if len(parts) == 0 {
+		return
+	}
+	// beginning with slash is now optional
+	for len(parts[i]) == 0 {
+		i++
+	}
+	hostPort = parts[i]
+	for i < len(parts)-1 {
+		i++
+		if len(path) > 0 {
+			path = path + "/" + parts[i]
+		} else {
+			path = parts[i]
+		}
+	}
+	glog.V(logger.Debug).Infof("host: '%s', path '%s' requested.", hostPort, path)
+	return
+}
+
+func (self *Api) parseAndResolve(uri string, nameresolver bool) (key storage.Key, hostPort, path string, err error) {
+	hostPort, path = parse(uri)
+	//resolving host and port
+	contentHash, err := self.Resolve(hostPort, nameresolver)
+	glog.V(logger.Debug).Infof("Resolved '%s' to contentHash: '%s', path: '%s'", uri, contentHash, path)
+	return contentHash[:], hostPort, path, err
+}
+
+// Put provides singleton manifest creation on top of dpa store
+func (self *Api) Put(content, contentType string) (string, error) {
+	r := strings.NewReader(content)
+	wg := &sync.WaitGroup{}
+	key, err := self.dpa.Store(r, int64(len(content)), wg, nil)
+	if err != nil {
+		return "", err
+	}
+	manifest := fmt.Sprintf(`{"entries":[{"hash":"%v","contentType":"%s"}]}`, key, contentType)
+	r = strings.NewReader(manifest)
+	key, err = self.dpa.Store(r, int64(len(manifest)), wg, nil)
+	if err != nil {
+		return "", err
+	}
+	wg.Wait()
+	return key.String(), nil
+}
+
+// Get uses iterative manifest retrieval and prefix matching
+// to resolve path to content using dpa retrieve
+// it returns a section reader, mimeType, status and an error
+func (self *Api) Get(uri string, nameresolver bool) (reader storage.LazySectionReader, mimeType string, status int, err error) {
+
+	key, _, path, err := self.parseAndResolve(uri, nameresolver)
+	quitC := make(chan bool)
+	trie, err := loadManifest(self.dpa, key, quitC)
+	if err != nil {
+		glog.V(logger.Warn).Infof("loadManifestTrie error: %v", err)
+		return
+	}
+
+	glog.V(logger.Detail).Infof("getEntry(%s)", path)
+	entry, _ := trie.getEntry(path)
+	if entry != nil {
+		key = common.Hex2Bytes(entry.Hash)
+		status = entry.Status
+		mimeType = entry.ContentType
+		glog.V(logger.Detail).Infof("content lookup key: '%v' (%v)", key, mimeType)
+		reader = self.dpa.Retrieve(key)
+	} else {
+		err = fmt.Errorf("manifest entry for '%s' not found", path)
+		glog.V(logger.Warn).Infof("%v", err)
+	}
+	return
+}
+
+func (self *Api) Modify(uri, contentHash, contentType string, nameresolver bool) (newRootHash string, err error) {
+	root, _, path, err := self.parseAndResolve(uri, nameresolver)
+	quitC := make(chan bool)
+	trie, err := loadManifest(self.dpa, root, quitC)
+	if err != nil {
+		return
+	}
+
+	if contentHash != "" {
+		entry := &manifestTrieEntry{
+			Path:        path,
+			Hash:        contentHash,
+			ContentType: contentType,
+		}
+		trie.addEntry(entry, quitC)
+	} else {
+		trie.deleteEntry(path, quitC)
+	}
+
+	err = trie.recalcAndStore()
+	if err != nil {
+		return
+	}
+	return trie.hash.String(), nil
+}