Add vendor (steam)

vendor/github.com/Philipp15b/go-steam/economy/inventory/partial.go

@@ -0,0 +1,91 @@
+package inventory
+
+import (
+	"bytes"
+	"encoding/json"
+	"errors"
+	"net/http"
+)
+
+// A partial inventory as sent by the Steam API.
+type PartialInventory struct {
+	Success bool
+	Error   string
+	Inventory
+	More      bool
+	MoreStart MoreStart `json:"more_start"`
+}
+
+type MoreStart uint
+
+func (m *MoreStart) UnmarshalJSON(data []byte) error {
+	if bytes.Equal(data, []byte("false")) {
+		return nil
+	}
+	return json.Unmarshal(data, (*uint)(m))
+}
+
+func DoInventoryRequest(client *http.Client, req *http.Request) (*PartialInventory, error) {
+	resp, err := client.Do(req)
+	if err != nil {
+		return nil, err
+	}
+	defer resp.Body.Close()
+
+	inv := new(PartialInventory)
+	err = json.NewDecoder(resp.Body).Decode(inv)
+	if err != nil {
+		return nil, err
+	}
+	return inv, nil
+}
+
+func GetFullInventory(getFirst func() (*PartialInventory, error), getNext func(start uint) (*PartialInventory, error)) (*Inventory, error) {
+	first, err := getFirst()
+	if err != nil {
+		return nil, err
+	}
+	if !first.Success {
+		return nil, errors.New("GetFullInventory API call failed: " + first.Error)
+	}
+
+	result := &first.Inventory
+	var next *PartialInventory
+	for latest := first; latest.More; latest = next {
+		next, err := getNext(uint(latest.MoreStart))
+		if err != nil {
+			return nil, err
+		}
+		if !next.Success {
+			return nil, errors.New("GetFullInventory API call failed: " + next.Error)
+		}
+
+		result = Merge(result, &next.Inventory)
+	}
+
+	return result, nil
+}
+
+// Merges the given Inventory into a single Inventory.
+// The given slice must have at least one element. The first element of the slice is used
+// and modified.
+func Merge(p ...*Inventory) *Inventory {
+	inv := p[0]
+	for idx, i := range p {
+		if idx == 0 {
+			continue
+		}
+
+		for key, value := range i.Items {
+			inv.Items[key] = value
+		}
+		for key, value := range i.Descriptions {
+			inv.Descriptions[key] = value
+		}
+		for key, value := range i.Currencies {
+			inv.Currencies[key] = value
+		}
+	}
+
+	return inv
+}