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Icon LinkBase Functionality

For implementation details on the Asset Library base functionality please see the Sway Libs Docs Icon Link.

Icon LinkImporting the Asset Library Base Functionality

In order to use base functionality the Asset Library, the Asset Library and the SRC-20 Icon Link Standard must be added to your Forc.toml file and then imported into your Sway project.

To add the Asset Library and the SRC-20 Icon Link Standard as a dependency to your Forc.toml file in your project, use the forc add command. 

forc add [email protected]
forc add [email protected]
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NOTE: Be sure to set the version to the latest release.

To import the Asset Library Base Functionality and SRC-20 Icon Link Standard to your Sway Smart Contract, add the following to your Sway file: 

use asset::base::*;
use src20::*;

Icon LinkIntegration with the SRC-20 Standard

The SRC-20 Icon Link definition states that the following abi implementation is required for any Native Asset on Fuel: 

abi SRC20 {
    #[storage(read)]
    fn total_assets() -> u64;
    #[storage(read)]
    fn total_supply(asset: AssetId) -> Option<u64>;
    #[storage(read)]
    fn name(asset: AssetId) -> Option<String>;
    #[storage(read)]
    fn symbol(asset: AssetId) -> Option<String>;
    #[storage(read)]
    fn decimals(asset: AssetId) -> Option<u8>;
}

The Asset Library has the following complimentary functions for each function in the SRC20 abi:

  • _total_assets()
  • _total_supply()
  • _name()
  • _symbol()
  • _decimals()

The following ABI and functions are also provided to set your SRC-20 Icon Link standard storage values: 

abi SetAssetAttributes {
    #[storage(write)]
    fn set_name(asset: AssetId, name: String);
    #[storage(write)]
    fn set_symbol(asset: AssetId, symbol: String);
    #[storage(write)]
    fn set_decimals(asset: AssetId, decimals: u8);
}
  • _set_name()
  • _set_symbol()
  • _set_decimals()
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NOTE The _set_name(), _set_symbol(), and _set_decimals() functions will set the attributes of an asset unconditionally. External checks should be applied to restrict the setting of attributes.

Icon LinkSetting Up Storage

Once imported, the Asset Library's base functionality should be available. To use them, be sure to add the storage block below to your contract which enables the SRC-20 Icon Link standard. 

storage {
    total_assets: u64 = 0,
    total_supply: StorageMap<AssetId, u64> = StorageMap {},
    name: StorageMap<AssetId, StorageString> = StorageMap {},
    symbol: StorageMap<AssetId, StorageString> = StorageMap {},
    decimals: StorageMap<AssetId, u8> = StorageMap {},
}

Icon LinkImplementing the SRC-20 Standard with the Asset Library

To use the Asset Library's base functionly, simply pass the StorageKey from the prescribed storage block. The example below shows the implementation of the SRC-20 Icon Link standard in combination with the Asset Library with no user defined restrictions or custom functionality. 

use asset::base::{_decimals, _name, _symbol, _total_assets, _total_supply};
use src20::SRC20;
use std::{hash::Hash, storage::storage_string::*, string::String};
 
// The SRC-20 storage block
storage {
    total_assets: u64 = 0,
    total_supply: StorageMap<AssetId, u64> = StorageMap {},
    name: StorageMap<AssetId, StorageString> = StorageMap {},
    symbol: StorageMap<AssetId, StorageString> = StorageMap {},
    decimals: StorageMap<AssetId, u8> = StorageMap {},
}
 
// Implement the SRC-20 Standard for this contract
impl SRC20 for Contract {
    #[storage(read)]
    fn total_assets() -> u64 {
        // Pass the `total_assets` StorageKey to `_total_assets()` from the Asset Library.
        _total_assets(storage.total_assets)
    }
 
    #[storage(read)]
    fn total_supply(asset: AssetId) -> Option<u64> {
        // Pass the `total_supply` StorageKey to `_total_supply()` from the Asset Library.
        _total_supply(storage.total_supply, asset)
    }
 
    #[storage(read)]
    fn name(asset: AssetId) -> Option<String> {
        // Pass the `name` StorageKey to `_name_()` from the Asset Library.
        _name(storage.name, asset)
    }
 
    #[storage(read)]
    fn symbol(asset: AssetId) -> Option<String> {
        // Pass the `symbol` StorageKey to `_symbol_()` function from the Asset Library.
        _symbol(storage.symbol, asset)
    }
 
    #[storage(read)]
    fn decimals(asset: AssetId) -> Option<u8> {
        // Pass the `decimals` StorageKey to `_decimals_()` function from the Asset Library.
        _decimals(storage.decimals, asset)
    }
}

Icon LinkSetting an Asset's SRC-20 Attributes

To set some the asset attributes for an Asset, use the SetAssetAttributes ABI provided by the Asset Library. The example below shows the implementation of the SetAssetAttributes ABI with no user defined restrictions or custom functionality. It is recommended that the Ownership Library is used in conjunction with the SetAssetAttributes ABI to ensure only a single user has permissions to set an Asset's attributes.

The _set_name(), _set_symbol(), and _set_decimals() functions follows the SRC-20 standard for logging and will emit their respective log when called. 

use asset::base::*;
use std::{hash::Hash, storage::storage_string::*, string::String};
 
storage {
    name: StorageMap<AssetId, StorageString> = StorageMap {},
    symbol: StorageMap<AssetId, StorageString> = StorageMap {},
    decimals: StorageMap<AssetId, u8> = StorageMap {},
}
 
impl SetAssetAttributes for Contract {
    #[storage(write)]
    fn set_name(asset: AssetId, name: String) {
        _set_name(storage.name, asset, name);
    }
 
    #[storage(write)]
    fn set_symbol(asset: AssetId, symbol: String) {
        _set_symbol(storage.symbol, asset, symbol);
    }
 
    #[storage(write)]
    fn set_decimals(asset: AssetId, decimals: u8) {
        _set_decimals(storage.decimals, asset, decimals);
    }
}
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NOTE The _set_name(), _set_symbol(), and _set_decimals() functions will set the attributes of an asset unconditionally. External checks should be applied to restrict the setting of attributes.