From 4716b70d56e9861d6480c42696093603ddd5f2a9 Mon Sep 17 00:00:00 2001
From: Lars Gierth <larsg@systemli.org>
Date: Sun, 19 Jun 2016 02:39:57 +0200
Subject: [PATCH] coreapi: start implementing it

License: MIT
Signed-off-by: Lars Gierth <larsg@systemli.org>
---
 core/coreapi/coreapi.go             | 64 +++++++++++++++++++++++++++++
 core/coreapi/interface/interface.go | 38 +++++++++++++++++
 2 files changed, 102 insertions(+)
 create mode 100644 core/coreapi/coreapi.go
 create mode 100644 core/coreapi/interface/interface.go

diff --git a/core/coreapi/coreapi.go b/core/coreapi/coreapi.go
new file mode 100644
index 00000000000..55c71318eab
--- /dev/null
+++ b/core/coreapi/coreapi.go
@@ -0,0 +1,64 @@
+package coreapi
+
+import (
+	core "github.com/ipfs/go-ipfs/core"
+	coreiface "github.com/ipfs/go-ipfs/core/coreapi/interface"
+	dag "github.com/ipfs/go-ipfs/merkledag"
+	path "github.com/ipfs/go-ipfs/path"
+	uio "github.com/ipfs/go-ipfs/unixfs/io"
+	context "gx/ipfs/QmZy2y8t9zQH2a1b8q2ZSLKp17ATuJoCNxxyMFG5qFExpt/go-net/context"
+)
+
+type CoreAPI struct {
+	ctx  context.Context
+	node *core.IpfsNode
+}
+
+func NewCoreAPI(ctx context.Context, node *core.IpfsNode) (*CoreAPI, error) {
+	api := &CoreAPI{ctx: ctx, node: node}
+	return api, nil
+}
+
+func (api *CoreAPI) Context() context.Context {
+	return api.ctx
+}
+
+func (api *CoreAPI) IpfsNode() *core.IpfsNode {
+	return api.node
+}
+
+func (api *CoreAPI) resolve(p string) (*dag.Node, error) {
+	dagnode, err := core.Resolve(api.ctx, api.node, path.Path(p))
+	if err == core.ErrNoNamesys && !api.node.OnlineMode() {
+		return nil, coreiface.ErrOffline
+	} else if err != nil {
+		return nil, err
+	}
+	return dagnode, nil
+}
+
+func (api *CoreAPI) Cat(p string) (coreiface.Data, error) {
+	dagnode, err := api.resolve(p)
+	if err != nil {
+		return nil, err
+	}
+	r, err := uio.NewDagReader(api.ctx, dagnode, api.node.DAG)
+	if err == uio.ErrIsDir {
+		return nil, coreiface.ErrDir
+	} else if err != nil {
+		return nil, err
+	}
+	return r, nil
+}
+
+func (api *CoreAPI) Ls(p string) ([]coreiface.Link, error) {
+	dagnode, err := api.resolve(p)
+	if err != nil {
+		return nil, err
+	}
+	links := make([]coreiface.Link, len(dagnode.Links))
+	for i, l := range dagnode.Links {
+		links[i] = coreiface.Link{Name: l.Name, Size: l.Size, Hash: l.Hash}
+	}
+	return links, nil
+}
diff --git a/core/coreapi/interface/interface.go b/core/coreapi/interface/interface.go
new file mode 100644
index 00000000000..4c40cc456c1
--- /dev/null
+++ b/core/coreapi/interface/interface.go
@@ -0,0 +1,38 @@
+package iface
+
+import (
+	"errors"
+	"io"
+
+	core "github.com/ipfs/go-ipfs/core"
+
+	mh "gx/ipfs/QmYf7ng2hG5XBtJA3tN34DQ2GUN5HNksEw1rLDkmr6vGku/go-multihash"
+	context "gx/ipfs/QmZy2y8t9zQH2a1b8q2ZSLKp17ATuJoCNxxyMFG5qFExpt/go-net/context"
+)
+
+type CoreAPI interface {
+	Context() context.Context
+	IpfsNode() *core.IpfsNode // XXX temporary
+	Cat(string) (Data, error)
+	Ls(string) ([]Link, error)
+}
+
+type Object struct {
+	Links []Link
+	Data  Data
+}
+
+type Link struct {
+	Name string // utf-8
+	Size uint64
+	Hash mh.Multihash
+}
+
+type Data interface {
+	io.Reader
+	io.Seeker
+	io.Closer
+}
+
+var ErrDir = errors.New("object is a directory")
+var ErrOffline = errors.New("can't resolve, ipfs node is offline")