https://github.com/ethereumjs/ethereumjs-vm/blob/master/docs/stateManager.md

StateManager

要与本博客的ethereumjs/ethereumjs-account-1-简介和API结合学习，然后你就能够发现StateManager其实就是得到账户中的值。账户 = 账户地址address + 账户状态（有nonce,balance,stateRoot,codeHash）。下面的方法得到或处理的就是账户中对应的这些数据信息

Interface for getting and setting data from an underlying state trie

从下面的状态前缀树得到和设置数据的接口

getAccount

Gets the ethereumjs-account associated with address. Returns an empty account if the account does not exist.

得到ethereumjs-account关联的地址。如果账户不存在则返回空账户

Parameters参数

• address Buffer Address of the account to get 要得到的账户的地址
• cb getAccount~callback 回调函数

getAccount~callback

Callback for getAccount method

Type: Function

Parameters

• error Error an error that may have happened or null  出现的错误或者null

• account Account An ethereumjs-account instance corresponding to the provided address 与提供的地址关联的ethereumjs-account实例


putAccount

Saves an ethereumjs-account into state under the provided address

将 ethereumjs-account保存在提供的地址下的状态中

Parameters

• address Buffer Address under which to store account  在该地址下存储账户

• account Account The ethereumjs-account to store 存储的 ethereumjs-account账户
• cb Function Callback function 回调函数

putContractCode

Adds value to the state trie as code, and sets codeHash on the account corresponding to address to reference this.

把值作为代码存储到状态前缀树中，并设置关联地址的账户的codeHash来引用它

Parameters

• address Buffer Address of the account to add the code for  为了该账户地址添加代码
• value Buffer The value of the code  代码的值

• cb Function Callback function 回调函数

getContractCode

Gets the code corresponding to the provided address

得到与提供的地址相关联的代码

Parameters参数

• address Buffer Address to get the code for  为了该地址取得代码
• cb getContractCode~callback回调函数

getContractCode~callback

Callback for getContractCode method

getContractCode方法的回调函数

Type: Function

Parameters

• error Error an error that may have happened or null 出现的错误或者null

• code Buffer The code corresponding to the provided address. Returns an empty Buffer if the account has no associated code. 与提供的代码相关联的代码。如果该账户没有相关联的代码就返回空Buffer

getContractStorage

Gets the storage value associated with the provided address and key

得到与提供的地址和key相关联的存储值

Parameters

• address Buffer Address of the account to get the storage for  为了该账户地址取得存储值
• key Buffer Key in the account's storage to get the value for   得到值需要的账户存储中的key
• cb getContractCode~callback

getContractStorage~callback

Callback for getContractStorage method

getContractStorage方法的回调

Type: Function

Parameters

• error Error an error that may have happened or null 出现的错误或者null

• storageValue Buffer The storage value for the account corresponding to the provided address at the provided key. If this does not exists an empty Buffer is returned  与提供的地址相关联的账户在提供的key处得到的存储值。如果不存在则返回空Buffer

putContractStorage

Adds value to the state trie for the account corresponding to address at the provided key

为了与地址相关联的账户在提供的key上给状态树添加值

Parameters

• address Buffer Address to set a storage value for 为了该地址设置值
• key Buffer Key to set the value at  将值设置在该key上
• value Buffer Value to set at key for account corresponding to address 为了与地址相关联的账户在key上设置的值

• cb Function Callback function 回调

clearContractStorage

Clears all storage entries for the account corresponding to address

为了与地址相关联的账户清理所有存储条目

Parameters

• address Buffer Address to clear the storage of  清理的存储所在的地址
• cb Function Callback function 回调函数

checkpoint检查点

Checkpoints the current state of the StateManager instance. State changes that follow can then be committed by calling commit or reverted by calling rollback.

检查点是StateManager实例的当前状态。随后的状态更改可以通过调用commit提交，也可以通过调用rollback返回

Parameters

• cb Function Callback function 回调函数

commit提交

Commits the current change-set to the instance since the last call to checkpoint.

提交目前的状态-设置为从上次调用检查点以来的实例

Parameters

• cb Function Callback function回调

revert

Reverts the current change-set to the instance since the last call to checkpoint.

恢复当前的变化-设置为从上次调用检查点以来的实例

Parameters

• cb Function Callback function

getStateRoot

Gets the state-root of the Merkle-Patricia trie representation of the state of this StateManager. Will error if there are uncommitted checkpoints on the instance.

得到StateManager状态的Merkle-Patricia前缀树表示的状态根。如果在实例中有未提交的检查点将出错

Parameters

• cb getStateRoot~callback

getStateRoot~callback

Callback for getStateRoot method

getStateRoot方法的回调

Type: Function

Parameters

• error Error an error that may have happened or null. Will be an error if the un-committed checkpoints on the instance.  出现的错误或null。如果在示例中有没提交的检查点将会变成一个错误
• stateRoot Buffer The state-root of the StateManager StateManager的状态根


setStateRoot

Sets the state of the instance to that represented by the provided stateRoot. Will error if there are uncommitted checkpoints on the instance or if the state root does not exist in the state trie.

设置通过提供的stateRoot表示的实例的状态。如果在实例中有未提交的检查点或在状态前缀树中状态根不存在将出错

Parameters

• stateRoot Buffer The state-root to reset the instance to  重置的实例的状态根
• cb Function Callback function 回调函数

generateCanonicalGenesis

Generates a canonical genesis state on the instance based on the configured chain parameters. Will error if there are uncommitted checkpoints on the instance.

基于在配置链参数在实例上生成规范生成状态。如果在实例上有未提交的检查点则出错

Parameters

• cb Function Callback function 回调函数

accountIsEmpty

Checks if the account corresponding to address is empty as defined in EIP-161 (https://github.com/ethereum/EIPs/blob/master/EIPS/eip-161.md)

查看与地址相关联的账户是否为空，就像 EIP-161中定义的一样。可看本博客（ethereum/EIPs-161 State trie clearing）

Parameters

• address Buffer Address to check 查看的地址
• cb accountIsEmpty~callback

accountIsEmpty~callback

Callback for accountIsEmpty method

accountIsEmpty方法的回调

Type: Function

Parameters

• error Error an error that may have happened or null  出现的错误或者null

• empty Boolean True if the account is empty false otherwise  如果账户为空则返回true，否则为false

cleanupTouchedAccounts

Removes accounts form the state trie that have been touched, as defined in EIP-161 (https://github.com/ethereum/EIPs/blob/master/EIPS/eip-161.md).

从状态前缀树中删除已修改的帐户，就像 EIP-161中定义的一样。可看本博客（ethereum/EIPs-161 State trie clearing）

Parameters

• cb Function Callback function

DefaultStateManager默认的StateManager

Default implementation of the StateManager interface

StateManager接口的默认实现

Parameters

• opts Object (optional, default {})
  • opts.common Common? Common parameters of the chain 链的Common参数
  • opts.trie Trie? a merkle-patricia-tree instance  merkle-patricia-tree实例

copy

Copies the current instance of the DefaultStateManager at the last fully committed point, i.e. as if all current checkpoints were reverted

在最后的完全提交点复制当前的DefaultStateManager实例，比如好像所有当前检查点都恢复了

dumpStorage

Dumps the the storage values for an account specified by address

为了被地址指定的账户倾倒存储值

Parameters

• address Buffer The address of the account to return storage for  为了改账户地址返回存储值
• cb dumpStorage~callback

dumpStorage~callback

Callback for dumpStorage method

dumpStorage方法的回调

Type: Function

Parameters

• error Error an error that may have happened or null  出现的错误或null

• accountState Object The state of the account as an Object map. Keys are are the storage keys, values are the storage values as strings. Both are represented as hex strings without the 0x prefix.作为对象映射的账户状态。Keys是存储键，values是字符串的存储值。都是没有0x前缀的十六进制表示的

hasGenesisState

Checks whether the current instance has the canonical genesis state for the configured chain parameters.

为了配置链参数查看是否当前的实例有规范生成状态

Parameters

• cb hasGenesisState~callback

hasGenesisState~callback

Callback for hasGenesisState method

hasGenesisState方法的回调

Type: Function

Parameters

• error Error an error that may have happened or null出现的错误或null
• hasGenesisState Boolean Whether the storage trie contains the canonical genesis state for the configured chain parameters.  存储前缀树是否为了配置链参数包含了规范生成状态

generateGenesis

Initializes the provided genesis state into the state trie

将提供的生成状态初始化到状态前缀树中

Parameters

• initState Object
• cb Function Callback function