1 files changed, 153 insertions, 0 deletions
diff --git a/vendor/github.com/felix/go-staticmaps/tile_fetcher.go b/vendor/github.com/felix/go-staticmaps/tile_fetcher.go
new file mode 100644
index 0000000..e02a71f
--- /dev/null
+++ b/vendor/github.com/felix/go-staticmaps/tile_fetcher.go
@@ -0,0 +1,153 @@
+// Copyright 2016 Florian Pigorsch. All rights reserved.
+//
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package sm
+
+import (
+	"bytes"
+	"fmt"
+	"image"
+	_ "image/jpeg" // to be able to decode jpegs
+	_ "image/png"  // to be able to decode pngs
+	"io"
+	"io/ioutil"
+	"log"
+	"net/http"
+	"os"
+	"path/filepath"
+
+	"github.com/Wessie/appdirs"
+)
+
+// TileFetcher downloads map tile images from a TileProvider
+type TileFetcher struct {
+	tileProvider *TileProvider
+	cacheDir     string
+	useCaching   bool
+}
+
+// NewTileFetcher creates a new Tilefetcher struct
+func NewTileFetcher(tileProvider *TileProvider) *TileFetcher {
+	t := new(TileFetcher)
+	t.tileProvider = tileProvider
+	app := appdirs.New("go-staticmaps", "flopp.net", "0.1")
+	t.cacheDir = fmt.Sprintf("%s/%s", app.UserCache(), tileProvider.Name)
+	t.useCaching = true
+	return t
+}
+
+func (t *TileFetcher) url(zoom, x, y int) string {
+	shard := ""
+	ss := len(t.tileProvider.Shards)
+	if len(t.tileProvider.Shards) > 0 {
+		shard = t.tileProvider.Shards[(x+y)%ss]
+	}
+	return t.tileProvider.getURL(shard, zoom, x, y)
+}
+
+func (t *TileFetcher) cacheFileName(zoom int, x, y int) string {
+	return fmt.Sprintf("%s/%d/%d/%d", t.cacheDir, zoom, x, y)
+}
+
+// ToggleCaching enables/disables caching
+func (t *TileFetcher) ToggleCaching(enabled bool) {
+	t.useCaching = enabled
+}
+
+// Fetch download (or retrieves from the cache) a tile image for the specified zoom level and tile coordinates
+func (t *TileFetcher) Fetch(zoom, x, y int) (image.Image, error) {
+	if t.useCaching {
+		fileName := t.cacheFileName(zoom, x, y)
+		cachedImg, err := t.loadCache(fileName)
+		if err == nil {
+			return cachedImg, nil
+		}
+	}
+
+	url := t.url(zoom, x, y)
+	data, err := t.download(url)
+	if err != nil {
+		return nil, err
+	}
+
+	img, _, err := image.Decode(bytes.NewBuffer(data))
+	if err != nil {
+		return nil, err
+	}
+
+	if t.useCaching {
+		fileName := t.cacheFileName(zoom, x, y)
+		if err := t.storeCache(fileName, data); err != nil {
+			log.Printf("Failed to store map tile as '%s': %s", fileName, err)
+		}
+	}
+
+	return img, nil
+}
+
+func (t *TileFetcher) download(url string) ([]byte, error) {
+	resp, err := http.Get(url)
+	defer resp.Body.Close()
+
+	if err != nil {
+		return nil, err
+	}
+
+	contents, err := ioutil.ReadAll(resp.Body)
+	if err != nil {
+		return nil, err
+	}
+
+	return contents, nil
+}
+
+func (t *TileFetcher) loadCache(fileName string) (image.Image, error) {
+	file, err := os.Open(fileName)
+	if err != nil {
+		return nil, err
+	}
+	defer file.Close()
+
+	img, _, err := image.Decode(file)
+	if err != nil {
+		return nil, err
+	}
+
+	return img, nil
+}
+
+func (t *TileFetcher) createCacheDir(path string) error {
+	src, err := os.Stat(path)
+	if err != nil {
+		if os.IsNotExist(err) {
+			return os.MkdirAll(path, 0777)
+		}
+		return err
+	}
+	if src.IsDir() {
+		return nil
+	}
+	return fmt.Errorf("File exists but is not a directory: %s", path)
+}
+
+func (t *TileFetcher) storeCache(fileName string, data []byte) error {
+	dir, _ := filepath.Split(fileName)
+
+	if err := t.createCacheDir(dir); err != nil {
+		return err
+	}
+
+	file, err := os.Create(fileName)
+	if err != nil {
+		return err
+	}
+	defer file.Close()
+
+	if _, err = io.Copy(file, bytes.NewBuffer(data)); err != nil {
+		return err
+	}
+
+	return nil
+}