mirror of
https://github.com/0glabs/0g-chain.git
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b5e162a930
* Change vault supply to shares * Update deposit shares * Use shares instead of supplied * Update tests, fix share calculation * Pass hard and savings keeper as pointer to earn keeper * Update remaining failing test * Add different share price test, fix comment for share price * Add shares amount to events * Additional share tests, use share to asset conversion for withdraw amount * Update VaultTotalValue test * Use sdk.Dec for vault shares instead of sdk.Int * Add test for expensive 20:1 shares * Update ConvertToShares comment for division, remove redundant test * Add vault share tests
83 lines
2.8 KiB
Go
83 lines
2.8 KiB
Go
package keeper
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import (
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"fmt"
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sdk "github.com/cosmos/cosmos-sdk/types"
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"github.com/kava-labs/kava/x/earn/types"
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)
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// ConvertToShares converts a given amount of tokens to shares.
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func (k *Keeper) ConvertToShares(ctx sdk.Context, assets sdk.Coin) (types.VaultShare, error) {
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totalShares, found := k.GetVaultTotalShares(ctx, assets.Denom)
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if !found {
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// No shares issued yet, so shares are issued 1:1
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return types.NewVaultShare(assets.Denom, assets.Amount.ToDec()), nil
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}
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totalValue, err := k.GetVaultTotalValue(ctx, assets.Denom)
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if err != nil {
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return types.VaultShare{}, err
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}
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if totalValue.Amount.IsZero() {
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return types.VaultShare{}, fmt.Errorf("total value of vault is zero")
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}
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// sharePrice = totalValue / totalShares
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// issuedShares = assets / sharePrice
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// issuedShares = assets / (totalValue / totalShares)
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// = assets * (totalShares / totalValue)
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// = (assets * totalShares) / totalValue
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//
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// Multiply by reciprocal of sharePrice to avoid two divisions and limit
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// rounding to one time. Per-share price is also not used as there is a loss
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// of precision.
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// Division is done at the last step as there is a slight amount that is
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// rounded down.
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// For example:
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// 100 * 100 / 105 == 10000 / 105 == 95.238095238095238095
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// 100 * (100 / 105) == 100 * 0.952380952380952380 == 95.238095238095238000
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// rounded down and truncated ^ loss of precision ^
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issuedShares := assets.Amount.ToDec().Mul(totalShares.Amount).QuoTruncate(totalValue.Amount.ToDec())
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if issuedShares.IsZero() {
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return types.VaultShare{}, fmt.Errorf("share count is zero")
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}
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return types.NewVaultShare(assets.Denom, issuedShares), nil
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}
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// ConvertToAssets converts a given amount of shares to tokens.
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func (k *Keeper) ConvertToAssets(ctx sdk.Context, share types.VaultShare) (sdk.Coin, error) {
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totalVaultShares, found := k.GetVaultTotalShares(ctx, share.Denom)
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if !found {
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return sdk.Coin{}, fmt.Errorf("vault for %s not found", share.Denom)
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}
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totalValue, err := k.GetVaultTotalValue(ctx, share.Denom)
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if err != nil {
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return sdk.Coin{}, err
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}
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// percentOwnership := accShares / totalVaultShares
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// accValue := totalValue * percentOwnership
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// accValue := totalValue * accShares / totalVaultShares
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// Division must be last to avoid rounding errors and properly truncate.
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value := totalValue.Amount.ToDec().Mul(share.Amount).QuoTruncate(totalVaultShares.Amount)
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return sdk.NewCoin(share.Denom, value.TruncateInt()), nil
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}
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// ShareIsDust returns true if the share value is less than 1 coin
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func (k *Keeper) ShareIsDust(ctx sdk.Context, share types.VaultShare) (bool, error) {
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coin, err := k.ConvertToAssets(ctx, share)
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if err != nil {
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return false, err
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}
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// Truncated int, becomes zero if < 1
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return coin.IsZero(), nil
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}
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