79 lines
1.9 KiB
Markdown
79 lines
1.9 KiB
Markdown
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---
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eip: 801
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title: Canary Standard
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author: ligi <ligi@ligi.de>
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type: Standards Track
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category: ERC
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status: Stagnant
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created: 2017-12-16
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---
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## Simple Summary
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A standard interface for canary contracts.
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## Abstract
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The following standard allows the implementation of canaries within contracts.
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This standard provides basic functionality to check if a canary is alive, keeping the canary alive and optionally manage feeders.
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## Motivation
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The canary can e.g. be used as a [warrant canary](https://en.wikipedia.org/wiki/Warrant_canary).
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A standard interface allows other applications to easily interface with canaries on Ethereum - e.g. for visualizing the state, automated alarms, applications to feed the canary or contracts (e.g. insurance) that use the state.
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## Specification
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### Methods
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#### isAlive()
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Returns if the canary was fed properly to signal e.g. that no warrant was received.
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``` js
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function isAlive() constant returns (bool alive)
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```
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#### getBlockOfDeath()
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Returns the block the canary died.
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Throws if the canary is alive.
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``` js
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function getBlockOfDeath() constant returns (uint256 block)
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```
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#### getType()
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Returns the type of the canary:
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* `1` = Simple (just the pure interface as defined in this ERC)
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* `2` = Single feeder (as defined in ERC-TBD)
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* `3` = Single feeder with bad food (as defined in ERC-TBD)
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* `4` = Multiple feeders (as defined in ERC-TBD)
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* `5` = Multiple mandatory feeders (as defined in ERC-TBD)
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* `6` = IOT (as defined in ERC-TBD)
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`1` might also be used for a special purpose contract that does not need a special type but still wants to expose the functions and provide events as defined in this ERC.
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``` js
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function getType() constant returns (uint8 type)
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```
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### Events
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#### RIP
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MUST trigger when the contract is called the first time after the canary died.
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``` js
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event RIP()
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```
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## Implementation
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TODO
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## Copyright
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Copyright and related rights waived via [CC0](../LICENSE.md).
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