// GetOrderBookSummary loads a summary of an order book identified by a
// selling/buying pair. It is designed to drive an order book summary client
// interface (bid/ask spread, prices and volume, etc).
func (q *Q) GetOrderBookSummary(dest interface{}, selling xdr.Asset, buying xdr.Asset) error {
var sql bytes.Buffer
var oq orderbookQueryBuilder
err := selling.Extract(&oq.SellingType, &oq.SellingCode, &oq.SellingIssuer)
if err != nil {
return err
}
err = buying.Extract(&oq.BuyingType, &oq.BuyingCode, &oq.BuyingIssuer)
if err != nil {
return err
}
oq.pushArg(20)
err = orderbookQueryTemplate.Execute(&sql, &oq)
if err != nil {
return errors.Wrap(err, 1)
}
err = q.SelectRaw(dest, sql.String(), oq.args...)
if err != nil {
return errors.Wrap(err, 1)
}
return nil
}
// ConnectedAssets loads xdr.Asset records for the purposes of path
// finding. Given the input asset type, a list of xdr.Assets is returned that
// each have some available trades for the input asset.
func (q *Q) ConnectedAssets(dest interface{}, selling xdr.Asset) error {
assets, ok := dest.(*[]xdr.Asset)
if !ok {
return errors.New("dest is not *[]xdr.Asset")
}
var (
t xdr.AssetType
c string
i string
)
err := selling.Extract(&t, &c, &i)
if err != nil {
return err
}
sql := sq.Select(
"buyingassettype AS type",
"coalesce(buyingassetcode, '') AS code",
"coalesce(buyingissuer, '') AS issuer").
From("offers").
Where(sq.Eq{"sellingassettype": t}).
GroupBy("buyingassettype", "buyingassetcode", "buyingissuer")
if t != xdr.AssetTypeAssetTypeNative {
sql = sql.Where(sq.Eq{"sellingassetcode": c, "sellingissuer": i})
}
var rows []struct {
Type xdr.AssetType
Code string
Issuer string
}
err = q.Select(&rows, sql)
if err != nil {
return err
}
results := make([]xdr.Asset, len(rows))
*assets = results
for i, r := range rows {
results[i], err = AssetFromDB(r.Type, r.Code, r.Issuer)
if err != nil {
return err
}
}
return nil
}
// Equals returns true if l and r are equivalent.
func Equals(l, r xdr.Asset) bool {
var le, re struct {
T xdr.AssetType
C string
I string
}
err := l.Extract(&le.T, &le.C, &le.I)
if err != nil {
panic(err)
}
err = r.Extract(&re.T, &re.C, &re.I)
if err != nil {
panic(err)
}
return le == re
}
// assetDetails sets the details for `a` on `result` using keys with `prefix`
func (is *Session) assetDetails(result map[string]interface{}, a xdr.Asset, prefix string) error {
var (
t string
code string
i string
)
err := a.Extract(&t, &code, &i)
if err != nil {
return err
}
result[prefix+"asset_type"] = t
if a.Type == xdr.AssetTypeAssetTypeNative {
return nil
}
result[prefix+"asset_code"] = code
result[prefix+"asset_issuer"] = i
return nil
}
// OfType filters the query to only effects of the given type.
func (q *EffectsQ) orderBookFilter(a xdr.Asset, prefix string) {
var typ, code, iss string
q.Err = a.Extract(&typ, &code, &iss)
if q.Err != nil {
return
}
if a.Type == xdr.AssetTypeAssetTypeNative {
clause := fmt.Sprintf(`
(heff.details->>'%sasset_type' = ?
AND heff.details ?? '%sasset_code' = false
AND heff.details ?? '%sasset_issuer' = false)`, prefix, prefix, prefix)
q.sql = q.sql.Where(clause, typ)
return
}
clause := fmt.Sprintf(`
(heff.details->>'%sasset_type' = ?
AND heff.details->>'%sasset_code' = ?
AND heff.details->>'%sasset_issuer' = ?)`, prefix, prefix, prefix)
q.sql = q.sql.Where(clause, typ, code, iss)
}
func (this *Asset) Populate(ctx context.Context, asset xdr.Asset) error {
return asset.Extract(&this.Type, &this.Code, &this.Issuer)
}