Godeps, vendor: convert dependency management to trash (#3198)

This commit converts the dependency management from Godeps to the vendor
folder, also switching the tool from godep to trash. Since the upstream tool
lacks a few features proposed via a few PRs, until those PRs are merged in
(if), use github.com/karalabe/trash.

You can update dependencies via trash --update.

All dependencies have been updated to their latest version.

Parts of the build system are reworked to drop old notions of Godeps and
invocation of the go vet command so that it doesn't run against the vendor
folder, as that will just blow up during vetting.

The conversion drops OpenCL (and hence GPU mining support) from ethash and our
codebase. The short reasoning is that there's noone to maintain and having
opencl libs in our deps messes up builds as go install ./... tries to build
them, failing with unsatisfied link errors for the C OpenCL deps.

golang.org/x/net/context is not vendored in. We expect it to be fetched by the
user (i.e. using go get). To keep ci.go builds reproducible the package is
"vendored" in build/_vendor.

vendor/github.com/rs/xhandler/.travis.yml

@@ -0,0 +1,7 @@
+language: go
+go:
+- 1.5
+- tip
+matrix:
+  allow_failures:
+      - go: tip

vendor/github.com/rs/xhandler/LICENSE

@@ -0,0 +1,19 @@
+Copyright (c) 2015 Olivier Poitrey <rs@dailymotion.com>
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is furnished
+to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.

vendor/github.com/rs/xhandler/README.md

@@ -0,0 +1,134 @@
+# XHandler
+
+[![godoc](http://img.shields.io/badge/godoc-reference-blue.svg?style=flat)](https://godoc.org/github.com/rs/xhandler) [![license](http://img.shields.io/badge/license-MIT-red.svg?style=flat)](https://raw.githubusercontent.com/rs/xhandler/master/LICENSE) [![Build Status](https://travis-ci.org/rs/xhandler.svg?branch=master)](https://travis-ci.org/rs/xhandler) [![Coverage](http://gocover.io/_badge/github.com/rs/xhandler)](http://gocover.io/github.com/rs/xhandler)
+
+XHandler is a bridge between [net/context](https://godoc.org/golang.org/x/net/context) and `http.Handler`.
+
+It lets you enforce `net/context` in your handlers without sacrificing compatibility with existing `http.Handlers` nor imposing a specific router.
+
+Thanks to `net/context` deadline management, `xhandler` is able to enforce a per request deadline and will cancel the context when the client closes the connection unexpectedly.
+
+You may create your own `net/context` aware handler pretty much the same way as you would do with http.Handler.
+
+Read more about xhandler on [Dailymotion engineering blog](http://engineering.dailymotion.com/our-way-to-go/).
+
+## Installing
+
+    go get -u github.com/rs/xhandler
+
+## Usage
+
+```go
+package main
+
+import (
+	"log"
+	"net/http"
+	"time"
+
+	"github.com/rs/cors"
+	"github.com/rs/xhandler"
+	"golang.org/x/net/context"
+)
+
+type myMiddleware struct {
+	next xhandler.HandlerC
+}
+
+func (h myMiddleware) ServeHTTPC(ctx context.Context, w http.ResponseWriter, r *http.Request) {
+	ctx = context.WithValue(ctx, "test", "World")
+	h.next.ServeHTTPC(ctx, w, r)
+}
+
+func main() {
+	c := xhandler.Chain{}
+
+	// Add close notifier handler so context is cancelled when the client closes
+	// the connection
+	c.UseC(xhandler.CloseHandler)
+
+	// Add timeout handler
+	c.UseC(xhandler.TimeoutHandler(2 * time.Second))
+
+	// Middleware putting something in the context
+	c.UseC(func(next xhandler.HandlerC) xhandler.HandlerC {
+		return myMiddleware{next: next}
+	})
+
+	// Mix it with a non-context-aware middleware handler
+	c.Use(cors.Default().Handler)
+
+	// Final handler (using handlerFuncC), reading from the context
+	xh := xhandler.HandlerFuncC(func(ctx context.Context, w http.ResponseWriter, r *http.Request) {
+		value := ctx.Value("test").(string)
+		w.Write([]byte("Hello " + value))
+	})
+
+	// Bridge context aware handlers with http.Handler using xhandler.Handle()
+	http.Handle("/test", c.Handler(xh))
+
+	if err := http.ListenAndServe(":8080", nil); err != nil {
+		log.Fatal(err)
+	}
+}
+```
+
+### Using xmux
+
+Xhandler comes with an optional context aware [muxer](https://github.com/rs/xmux) forked from [httprouter](https://github.com/julienschmidt/httprouter):
+
+```go
+package main
+
+import (
+	"fmt"
+	"log"
+	"net/http"
+	"time"
+
+	"github.com/rs/xhandler"
+	"github.com/rs/xmux"
+	"golang.org/x/net/context"
+)
+
+func main() {
+	c := xhandler.Chain{}
+
+	// Append a context-aware middleware handler
+	c.UseC(xhandler.CloseHandler)
+
+	// Another context-aware middleware handler
+	c.UseC(xhandler.TimeoutHandler(2 * time.Second))
+
+	mux := xmux.New()
+
+	// Use c.Handler to terminate the chain with your final handler
+	mux.GET("/welcome/:name", xhandler.HandlerFuncC(func(ctx context.Context, w http.ResponseWriter, req *http.Request) {
+		fmt.Fprintf(w, "Welcome %s!", xmux.Params(ctx).Get("name"))
+	}))
+
+	if err := http.ListenAndServe(":8080", c.Handler(mux)); err != nil {
+		log.Fatal(err)
+	}
+}
+```
+
+See [xmux](https://github.com/rs/xmux) for more examples.
+
+## Context Aware Middleware
+
+Here is a list of `net/context` aware middleware handlers implementing `xhandler.HandlerC` interface.
+
+Feel free to put up a PR linking your middleware if you have built one:
+
+| Middleware | Author | Description |
+| ---------- | ------ | ----------- |
+| [xmux](https://github.com/rs/xmux) | [Olivier Poitrey](https://github.com/rs) | HTTP request muxer |
+| [xlog](https://github.com/rs/xlog) | [Olivier Poitrey](https://github.com/rs) | HTTP handler logger |
+| [xstats](https://github.com/rs/xstats) | [Olivier Poitrey](https://github.com/rs) | A generic client for service instrumentation |
+| [xaccess](https://github.com/rs/xaccess) | [Olivier Poitrey](https://github.com/rs) | HTTP handler access logger with [xlog](https://github.com/rs/xlog) and [xstats](https://github.com/rs/xstats) |
+| [cors](https://github.com/rs/cors) | [Olivier Poitrey](https://github.com/rs) | [Cross Origin Resource Sharing](http://www.w3.org/TR/cors/) (CORS) support |
+
+## Licenses
+
+All source code is licensed under the [MIT License](https://raw.github.com/rs/xhandler/master/LICENSE).

vendor/github.com/rs/xhandler/chain.go

@@ -0,0 +1,121 @@
+package xhandler
+
+import (
+	"net/http"
+
+	"golang.org/x/net/context"
+)
+
+// Chain is a helper for chaining middleware handlers together for easier
+// management.
+type Chain []func(next HandlerC) HandlerC
+
+// Add appends a variable number of additional middleware handlers
+// to the middleware chain. Middleware handlers can either be
+// context-aware or non-context aware handlers with the appropriate
+// function signatures.
+func (c *Chain) Add(f ...interface{}) {
+	for _, h := range f {
+		switch v := h.(type) {
+		case func(http.Handler) http.Handler:
+			c.Use(v)
+		case func(HandlerC) HandlerC:
+			c.UseC(v)
+		default:
+			panic("Adding invalid handler to the middleware chain")
+		}
+	}
+}
+
+// With creates a new middleware chain from an existing chain,
+// extending it with additional middleware. Middleware handlers
+// can either be context-aware or non-context aware handlers
+// with the appropriate function signatures.
+func (c *Chain) With(f ...interface{}) *Chain {
+	n := make(Chain, len(*c))
+	copy(n, *c)
+	n.Add(f...)
+	return &n
+}
+
+// UseC appends a context-aware handler to the middleware chain.
+func (c *Chain) UseC(f func(next HandlerC) HandlerC) {
+	*c = append(*c, f)
+}
+
+// Use appends a standard http.Handler to the middleware chain without
+// losing track of the context when inserted between two context aware handlers.
+//
+// Caveat: the f function will be called on each request so you are better off putting
+// any initialization sequence outside of this function.
+func (c *Chain) Use(f func(next http.Handler) http.Handler) {
+	xf := func(next HandlerC) HandlerC {
+		return HandlerFuncC(func(ctx context.Context, w http.ResponseWriter, r *http.Request) {
+			n := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+				next.ServeHTTPC(ctx, w, r)
+			})
+			f(n).ServeHTTP(w, r)
+		})
+	}
+	*c = append(*c, xf)
+}
+
+// Handler wraps the provided final handler with all the middleware appended to
+// the chain and returns a new standard http.Handler instance.
+// The context.Background() context is injected automatically.
+func (c Chain) Handler(xh HandlerC) http.Handler {
+	ctx := context.Background()
+	return c.HandlerCtx(ctx, xh)
+}
+
+// HandlerFC is a helper to provide a function (HandlerFuncC) to Handler().
+//
+// HandlerFC is equivalent to:
+//  c.Handler(xhandler.HandlerFuncC(xhc))
+func (c Chain) HandlerFC(xhf HandlerFuncC) http.Handler {
+	ctx := context.Background()
+	return c.HandlerCtx(ctx, HandlerFuncC(xhf))
+}
+
+// HandlerH is a helper to provide a standard http handler (http.HandlerFunc)
+// to Handler(). Your final handler won't have access to the context though.
+func (c Chain) HandlerH(h http.Handler) http.Handler {
+	ctx := context.Background()
+	return c.HandlerCtx(ctx, HandlerFuncC(func(ctx context.Context, w http.ResponseWriter, r *http.Request) {
+		h.ServeHTTP(w, r)
+	}))
+}
+
+// HandlerF is a helper to provide a standard http handler function
+// (http.HandlerFunc) to Handler(). Your final handler won't have access
+// to the context though.
+func (c Chain) HandlerF(hf http.HandlerFunc) http.Handler {
+	ctx := context.Background()
+	return c.HandlerCtx(ctx, HandlerFuncC(func(ctx context.Context, w http.ResponseWriter, r *http.Request) {
+		hf(w, r)
+	}))
+}
+
+// HandlerCtx wraps the provided final handler with all the middleware appended to
+// the chain and returns a new standard http.Handler instance.
+func (c Chain) HandlerCtx(ctx context.Context, xh HandlerC) http.Handler {
+	return New(ctx, c.HandlerC(xh))
+}
+
+// HandlerC wraps the provided final handler with all the middleware appended to
+// the chain and returns a HandlerC instance.
+func (c Chain) HandlerC(xh HandlerC) HandlerC {
+	for i := len(c) - 1; i >= 0; i-- {
+		xh = c[i](xh)
+	}
+	return xh
+}
+
+// HandlerCF wraps the provided final handler func with all the middleware appended to
+// the chain and returns a HandlerC instance.
+//
+// HandlerCF is equivalent to:
+//  c.HandlerC(xhandler.HandlerFuncC(xhc))
+func (c Chain) HandlerCF(xhc HandlerFuncC) HandlerC {
+	return c.HandlerC(HandlerFuncC(xhc))
+}

vendor/github.com/rs/xhandler/middleware.go

@@ -0,0 +1,59 @@
+package xhandler
+
+import (
+	"net/http"
+	"time"
+
+	"golang.org/x/net/context"
+)
+
+// CloseHandler returns a Handler, cancelling the context when the client
+// connection closes unexpectedly.
+func CloseHandler(next HandlerC) HandlerC {
+	return HandlerFuncC(func(ctx context.Context, w http.ResponseWriter, r *http.Request) {
+		// Cancel the context if the client closes the connection
+		if wcn, ok := w.(http.CloseNotifier); ok {
+			var cancel context.CancelFunc
+			ctx, cancel = context.WithCancel(ctx)
+			defer cancel()
+
+			notify := wcn.CloseNotify()
+			go func() {
+				select {
+				case <-notify:
+					cancel()
+				case <-ctx.Done():
+				}
+			}()
+		}
+
+		next.ServeHTTPC(ctx, w, r)
+	})
+}
+
+// TimeoutHandler returns a Handler which adds a timeout to the context.
+//
+// Child handlers have the responsability of obeying the context deadline and to return
+// an appropriate error (or not) response in case of timeout.
+func TimeoutHandler(timeout time.Duration) func(next HandlerC) HandlerC {
+	return func(next HandlerC) HandlerC {
+		return HandlerFuncC(func(ctx context.Context, w http.ResponseWriter, r *http.Request) {
+			ctx, _ = context.WithTimeout(ctx, timeout)
+			next.ServeHTTPC(ctx, w, r)
+		})
+	}
+}
+
+// If is a special handler that will skip insert the condNext handler only if a condition
+// applies at runtime.
+func If(cond func(ctx context.Context, w http.ResponseWriter, r *http.Request) bool, condNext func(next HandlerC) HandlerC) func(next HandlerC) HandlerC {
+	return func(next HandlerC) HandlerC {
+		return HandlerFuncC(func(ctx context.Context, w http.ResponseWriter, r *http.Request) {
+			if cond(ctx, w, r) {
+				condNext(next).ServeHTTPC(ctx, w, r)
+			} else {
+				next.ServeHTTPC(ctx, w, r)
+			}
+		})
+	}
+}

vendor/github.com/rs/xhandler/xhandler.go

@@ -0,0 +1,42 @@
+// Package xhandler provides a bridge between http.Handler and net/context.
+//
+// xhandler enforces net/context in your handlers without sacrificing
+// compatibility with existing http.Handlers nor imposing a specific router.
+//
+// Thanks to net/context deadline management, xhandler is able to enforce
+// a per request deadline and will cancel the context in when the client close
+// the connection unexpectedly.
+//
+// You may create net/context aware middlewares pretty much the same way as
+// you would with http.Handler.
+package xhandler // import "github.com/rs/xhandler"
+
+import (
+	"net/http"
+
+	"golang.org/x/net/context"
+)
+
+// HandlerC is a net/context aware http.Handler
+type HandlerC interface {
+	ServeHTTPC(context.Context, http.ResponseWriter, *http.Request)
+}
+
+// HandlerFuncC type is an adapter to allow the use of ordinary functions
+// as an xhandler.Handler. If f is a function with the appropriate signature,
+// xhandler.HandlerFuncC(f) is a xhandler.Handler object that calls f.
+type HandlerFuncC func(context.Context, http.ResponseWriter, *http.Request)
+
+// ServeHTTPC calls f(ctx, w, r).
+func (f HandlerFuncC) ServeHTTPC(ctx context.Context, w http.ResponseWriter, r *http.Request) {
+	f(ctx, w, r)
+}
+
+// New creates a conventional http.Handler injecting the provided root
+// context to sub handlers. This handler is used as a bridge between conventional
+// http.Handler and context aware handlers.
+func New(ctx context.Context, h HandlerC) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		h.ServeHTTPC(ctx, w, r)
+	})
+}