OracleAdapter

The OracleAdapter is the single interface the FPMM pool uses to obtain the swap rate. It returns a rate only when it is valid; otherwise it reverts. Validity combines: recency of the feed, trading mode from BreakerBox (e.g. trading suspended when a breaker has tripped), and, for FX pairs, FX market hours. The pool calls getFXRateIfValid(rateFeedID) on every quote and swap; if the adapter reverts, the swap path reverts.

Contract: mento-protocol/mento-core — contracts/oracles/OracleAdapter.sol

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Using the OracleAdapter (code examples)

Most integrations do not call the OracleAdapter directly: the FPMM pool calls it for every getAmountOut and swap. Use the adapter directly when you need to check rate validity (e.g. before showing a quote in a UI) or read the current rate for off-chain logic.

Getting a valid rate (for swaps / quoting)

If you are implementing custom swap logic and need the same rate the pool would use, call the same method the pool uses. Reverts if FX market is closed, trading is suspended, or the rate is stale:

IOracleAdapter adapter = IOracleAdapter(adapterAddress);
address rateFeedID = referenceRateFeedID; // e.g. pool’s referenceRateFeedID

(uint256 numerator, uint256 denominator) = adapter.getFXRateIfValid(rateFeedID);
// Rate = numerator / denominator (e.g. token1 per token0, 1e18 scale)

Checking validity without using the rate

Useful to decide whether to show “trading available” or “market closed / suspended”:

try adapter.ensureRateValid(rateFeedID) {
    // Rate is valid; safe to quote/swap
} catch {
    // TradingSuspended, NoRecentRate, or (for getFXRateIfValid) FXMarketClosed
}

Inspecting rate and status (no revert)

Get the raw rate and flags without reverting. Use for dashboards or conditional logic:

IOracleAdapter.RateInfo memory info = adapter.getRate(rateFeedID);
// info.numerator, info.denominator
// info.tradingMode  == 0 means bidirectional (trading allowed)
// info.isRecent     == true if within report expiry
// info.isFXMarketOpen

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State

Field	Meaning
sortedOracles	Source of the median rate and timestamp for a given rateFeedID.
breakerBox	Provides trading mode per rate feed (e.g. bidirectional vs suspended).
marketHoursBreaker	Provides FX market open/closed for the current block timestamp.
l2SequencerUptimeFeed	Optional Chainlink L2 sequencer feed; if set, can be used to gate on sequencer uptime.

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Rate feed ID

Each price feed is identified by a rateFeedID (an address). For CELO/cStable the ID is the stable token address. For other pairs (e.g. USDC/USD, EUR/USD) the ID is typically derived as address(uint160(uint256(keccak256(abi.encodePacked(asset0, asset1))))). Relayed Chainlink feeds often use a prefix (e.g. "relayed:PHPUSD"). The FPMM pool stores a referenceRateFeedID and passes it to the adapter.

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Main entrypoints (for the pool)

• getFXRateIfValid(rateFeedID) — Returns (numerator, denominator) only if:

  1. FX market is open (marketHoursBreaker.isFXMarketOpen(block.timestamp)).

  2. Trading mode for this feed is bidirectional (breakerBox.getRateFeedTradingMode(rateFeedID) == TRADING_MODE_BIDIRECTIONAL).

  3. Recent rate: medianTimestamp(rateFeedID) >= block.timestamp - reportExpiry (report expiry comes from sortedOracles.getTokenReportExpirySeconds(rateFeedID)). Otherwise reverts with FXMarketClosed, TradingSuspended, or NoRecentRate.

• getRateIfValid(rateFeedID) — Same as above but does not check FX market hours. Used when market-hours gating is not required.

• ensureRateValid(rateFeedID) — View that reverts if the rate would not be valid (trading mode or recency); does not return the rate. Useful for pre-checks.

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Rate source

• getRate(rateFeedID) — Returns a RateInfo struct: (numerator, denominator, tradingMode, isRecent, isFXMarketOpen) without reverting. The actual rate comes from sortedOracles.medianRate(rateFeedID). The adapter normalizes the denominator (SortedOracles uses 1e24; the adapter exposes 1e18 after scaling). So the pool always gets the rate via the validity-gated path (getFXRateIfValid), not the raw median.

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L2 sequencer

• isL2SequencerUp(since) — If l2SequencerUptimeFeed is set, returns whether the sequencer has been up for at least since seconds (and answer is 0). If the feed is not set, returns true. Used on L2s to avoid using stale rates right after sequencer recovery.

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Errors

• FXMarketClosed — getFXRateIfValid called when FX market hours say closed.

• TradingSuspended — BreakerBox trading mode is not bidirectional for this feed.

• NoRecentRate — Median timestamp is older than block.timestamp - reportExpiry.

• InvalidRate — Median rate numerator or denominator is zero.

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See also

• BreakerBox — Circuit breakers and trading mode.

• FPMM — Pool calls getFXRateIfValid.

• Dive Deeper: Oracles & circuit breakers.