Class BlockPolicy<T>

A default implementation of IBlockPolicy<T> interface.

Inheritance

Object

BlockPolicy<T>

Implements

IBlockPolicy<T>

Namespace: Libplanet.Blockchain.Policies

Assembly: Libplanet.dll

Syntax

public class BlockPolicy<T> : object, IBlockPolicy<T> where T : IAction, new()

Type Parameters

Name	Description
T	An IAction type. It should match to Block<T>'s type parameter.

Constructors

BlockPolicy(IAction, Nullable<TimeSpan>, Nullable<Int64>, Nullable<Int64>, Nullable<Func<BlockChain<T>, Transaction<T>, TxPolicyViolationException>>, Nullable<Func<BlockChain<T>, Block<T>, BlockPolicyViolationException>>, Nullable<IComparer<IBlockExcerpt>>, Nullable<Func<Int64, Int64>>, Nullable<Func<Int64, Int32>>, Nullable<Func<Int64, Int32>>, Nullable<Func<Int64, Int32>>, Nullable<IImmutableSet<Currency>>)

Creates a default BlockPolicy<T> instance.

Each unprovided argument will be assigned a default value. See each parameter description for more detail.

Declaration

public BlockPolicy(IAction blockAction = null, TimeSpan? blockInterval = null, long? difficultyStability = null, long? minimumDifficulty = null, Func<BlockChain<T>, Transaction<T>, TxPolicyViolationException>? validateNextBlockTx = null, Func<BlockChain<T>, Block<T>, BlockPolicyViolationException>? validateNextBlock = null, IComparer<IBlockExcerpt>? canonicalChainComparer = null, Func<long, long>? getMaxBlockBytes = null, Func<long, int>? getMinTransactionsPerBlock = null, Func<long, int>? getMaxTransactionsPerBlock = null, Func<long, int>? getMaxTransactionsPerSignerPerBlock = null, IImmutableSet<Currency>? nativeTokens = null)

Parameters

Type	Name	Description
IAction	blockAction	A IAction to executed for every Block<T>. Set to null by default, which results in no additional execution other than those included in Transaction<T>s.
Nullable<TimeSpan>	blockInterval	Goes to BlockInterval. Set to DefaultTargetBlockInterval by default.
Nullable<Int64>	difficultyStability	Goes to DifficultyStability. Set to DefaultDifficultyStability by default.
Nullable<Int64>	minimumDifficulty	Goes to MinimumDifficulty. Set to DefaultMinimumDifficulty by default.
Nullable<Func<BlockChain<T>, Transaction<T>, TxPolicyViolationException>>	validateNextBlockTx	The predicate that determines if a Transaction<T> follows the policy. Set to a constant function of null by default.
Nullable<Func<BlockChain<T>, Block<T>, BlockPolicyViolationException>>	validateNextBlock	The predicate that determines if a Block<T> follows the policy. Set to a default implementation where block's hash algorithm type, bytes count, and transactions count are validated.
Nullable<IComparer<IBlockExcerpt>>	canonicalChainComparer	The custom rule to determine which is the canonical chain. If omitted, TotalDifficultyComparer is used by default.
Nullable<Func<Int64, Int64>>	getMaxBlockBytes	The function determining the maximum size of a Block<T> in number of bytes given its Index. Goes to GetMaxBlockBytes(Int64). Set to a constant size of 100KiB, i.e. 100 * 1024, by default.
Nullable<Func<Int64, Int32>>	getMinTransactionsPerBlock	The function determining the minimum number of Transaction<T>s that must be included in a Block<T>. Goes to GetMinTransactionsPerBlock(Int64). Set to a constant function of 0 by default.
Nullable<Func<Int64, Int32>>	getMaxTransactionsPerBlock	The function determining how many Transaction<T>s can be included in a Block<T>. Goes to GetMaxTransactionsPerBlock(Int64). Set to a constant function of 100 by default.
Nullable<Func<Int64, Int32>>	getMaxTransactionsPerSignerPerBlock	The function determining the maximum number of transactions from the same signer that can be included in a Block<T> given the Block<T>'s index. Goes to GetMaxTransactionsPerSignerPerBlock(Int64). Set to GetMaxTransactionsPerBlock(Int64) by default.
Nullable<IImmutableSet<Currency>>	nativeTokens	A fixed set of Currency objects that are supported by the blockchain as first-class citizens. Empty by default.

Properties

BlockAction

An IAction to execute and be rendered for every block, if any.

Declaration

public IAction BlockAction { get; }

Property Value

Type	Description
IAction

BlockInterval

Targeted time interval between two consecutive Block<T>s. See the corresponding parameter description for BaseAlgorithm(BlockChain<T>, TimeSpan, Int64, Int64) for full detail.

Declaration

public TimeSpan BlockInterval { get; }

Property Value

Type	Description
TimeSpan

CanonicalChainComparer

A comparer to determine which branch is the canonical chain (i.e., best chain). The most greater one according to this comparer is considered to be the canon.

Declaration

public IComparer<IBlockExcerpt> CanonicalChainComparer { get; }

Property Value

Type	Description
IComparer<IBlockExcerpt>

See Also

IBlockExcerpt

TotalDifficultyComparer

DifficultyStability

Stability of a series of difficulties for a BlockChain<T>. See the corresponding parameter description for BaseAlgorithm(BlockChain<T>, TimeSpan, Int64, Int64) for full detail.

Declaration

public long DifficultyStability { get; }

Property Value

Type	Description
Int64

MinimumDifficulty

Minimum difficulty for a Block<T>. See the corresponding parameter description for BaseAlgorithm(BlockChain<T>, TimeSpan, Int64, Int64) for full detail.

Declaration

public long MinimumDifficulty { get; }

Property Value

Type	Description
Int64

NativeTokens

A fixed set of Currency objects that are supported by the blockchain as first-class assets.

Declaration

public IImmutableSet<Currency> NativeTokens { get; }

Property Value

Type	Description
IImmutableSet<Currency>

Methods

GetMaxBlockBytes(Int64)

Gets the maximum length of a Block<T> in bytes.

Declaration

public long GetMaxBlockBytes(long index)

Parameters

Type	Name	Description
Int64	index	The Index of the Block<T> for which this constraint should apply.

Returns

Type	Description
Int64	The maximum length of a Block<T> in bytes to accept.

GetMaxTransactionsPerBlock(Int64)

Gets the maximum number of Transaction<T>s allowed for a valid Block<T>.

Declaration

public int GetMaxTransactionsPerBlock(long index)

Parameters

Type	Name	Description
Int64	index	The Index of the Block<T> for which this constraint should apply.

Returns

Type	Description
Int32	The maximum number of Transaction<T>s allowed for a valid Block<T> can accept.

GetMaxTransactionsPerSignerPerBlock(Int64)

Gets the maximum number of Transaction<T>s allowed per signer for a valid Block<T>.

Declaration

public int GetMaxTransactionsPerSignerPerBlock(long index)

Parameters

Type	Name	Description
Int64	index	The Index of the Block<T> for which this constraint should apply.

Returns

Type	Description
Int32	The maximum number of Transaction<T>s allowed per signer for a valid Block<T> can accept.

GetMinTransactionsPerBlock(Int64)

Gets the minimum number of Transaction<T>s allowed for a valid Block<T>.

Declaration

public int GetMinTransactionsPerBlock(long index)

Parameters

Type	Name	Description
Int64	index	The Index of the Block<T> for which this constraint should apply.

Returns

Type	Description
Int32	The minimum number of Transaction<T>s allowed for a valid Block<T> can accept.

GetNextBlockDifficulty(BlockChain<T>)

Determines a right Difficulty for a new Block<T> to be mined right after the given blockChain.

Declaration

public virtual long GetNextBlockDifficulty(BlockChain<T> blockChain)

Parameters

Type	Name	Description
BlockChain<T>	blockChain	Consecutive Block<T>s to be followed by a new Block<T> to be mined.

Returns

Type	Description
Int64	A right Difficulty for a new Block<T> to be mined.

ValidateNextBlock(BlockChain<T>, Block<T>)

Checks if a Block<T> can be appended to the given BlockChain<T>.

Declaration

public virtual BlockPolicyViolationException ValidateNextBlock(BlockChain<T> blockChain, Block<T> nextBlock)

Parameters

Type	Name	Description
BlockChain<T>	blockChain	The target BlockChain<T> to append nextBlock.
Block<T>	nextBlock	The next block to append to blockChain.

Returns

Type	Description
BlockPolicyViolationException	A BlockPolicyViolationException with a description as to why given nextBlock is invalid, or null if nextBlock is valid.

Remarks

Note that ValidateNextBlockTx(BlockChain<T>, Transaction<T>) will be called separately from a BlockChain<T> when appending a Block<T>. Hence, to reduce redundancy, an implementation of this interface should not call ValidateNextBlockTx(BlockChain<T>, Transaction<T>).

ValidateNextBlockTx(BlockChain<T>, Transaction<T>)

Checks if a Transaction<T> can be included in a yet to be mined Block<T> that can be appended to the given BlockChain<T>.

Declaration

public virtual TxPolicyViolationException ValidateNextBlockTx(BlockChain<T> blockChain, Transaction<T> transaction)

Parameters

Type	Name	Description
BlockChain<T>	blockChain	The target BlockChain<T> to include given transaction.
Transaction<T>	transaction	The Transaction<T> to consider.

Returns

Type	Description
TxPolicyViolationException	A TxPolicyViolationException with a description as to why given transaction is invalid, or null if transaction is valid.

Remarks

This is used in two different cases:

• When selecting which Transaction<T> to include when mining a next Block<T>.
• When appending a Block<T> with transaction to a BlockChain<T>.

This is called separately from ValidateNextBlock(BlockChain<T>, Block<T>) from a BlockChain<T>.

Implements

IBlockPolicy<T>