【移動(dòng)應(yīng)用開發(fā)技術(shù)】Android Web3j OOM解決詳解

【移動(dòng)應(yīng)用開發(fā)技術(shù)】AndroidWeb3jOOM解決詳解

在Android客戶端使用Web3j創(chuàng)建錢包、導(dǎo)入錢包時(shí)都可能會(huì)產(chǎn)生OOM，相關(guān)issue在Github上已經(jīng)有所提及：/web3j/web3j/issues/299。這個(gè)問題在Web3j3.0版本以前是沒有的，由于新版的Web3j使用spongycastle庫替換了lambdaworks庫，雖然在效率上提升了速度，但存在Android端的兼容性問題。本項(xiàng)目代碼地址：/uncleleonfan/WalletOOM.git創(chuàng)建錢包OOM解決

在創(chuàng)建錢包時(shí)，如果創(chuàng)建一個(gè)FullWallet，則會(huì)導(dǎo)致OOM：Log如下：

"Causedby:java.lang.OutOfMemoryError:Failedtoallocatea1036byteallocationwith16777216freebytesand48MBuntilOOM;failedduetofragmentation(requiredcontinguousfree16384bytesforanewbufferwherelargestcontiguousfree8192bytes)",

"\tatorg.spongycastle.util.Arrays.clone(Arrays.java:602)",

"\tatorg.spongycastle.crypto.generators.SCrypt.SMix(SCrypt.java:126)",

"\tatorg.spongycastle.crypto.generators.SCrypt.MFcrypt(SCrypt.java:87)",

"\tatorg.spongycastle.crypto.generators.SCrypt.generate(SCrypt.java:66)",

"\tatorg.web3j.crypto.Wallet.generateDerivedScryptKey(Wallet.java:136)",

"\tatorg.web3j.crypto.Wallet.create(Wallet.java:74)",

"\tatorg.web3j.crypto.Wallet.createStandard(Wallet.java:93)",

"\tatorg.web3j.crypto.WalletUtils.generateWalletFile(WalletUtils.java:61)"

"Causedby:java.lang.OutOfMemoryError:Failedtoallocatea1036byteallocationwith16777216freebytesand48MBuntilOOM;failedduetofragmentation(requiredcontinguousfree16384bytesforanewbufferwherelargestcontiguousfree8192bytes)",

"\tatorg.spongycastle.util.Arrays.clone(Arrays.java:602)",

"\tatorg.spongycastle.crypto.generators.SCrypt.SMix(SCrypt.java:126)",

"\tatorg.spongycastle.crypto.generators.SCrypt.MFcrypt(SCrypt.java:87)",

"\tatorg.spongycastle.crypto.generators.SCrypt.generate(SCrypt.java:66)",

"\tatorg.web3j.crypto.Wallet.generateDerivedScryptKey(Wallet.java:136)",

"\tatorg.web3j.crypto.Wallet.create(Wallet.java:74)",

"\tatorg.web3j.crypto.Wallet.createStandard(Wallet.java:93)",

"\tatorg.web3j.crypto.WalletUtils.generateWalletFile(WalletUtils.java:61)"

generateFullNewWalletFile里面會(huì)調(diào)用createStandard創(chuàng)建錢包，使用N_STANDARD，P_STANDARD來配置加密強(qiáng)度，直接影響需使用的內(nèi)存大小，最終導(dǎo)致OOM的發(fā)生。解決方法非常簡單，創(chuàng)建一個(gè)LightWallet即可：generateLightNewWalletFile會(huì)調(diào)用createLight來創(chuàng)建一個(gè)輕錢包，使用N_LIGHT，P_LIGHT，他們在數(shù)值上相對較小，所以不會(huì)OOM。我們可以對比一下N_STANDARD和P_STANDARD，N_LIGHT和P_LIGHT的大小：導(dǎo)入錢包OOM解決

當(dāng)我們導(dǎo)入一個(gè)輕錢包時(shí)，不會(huì)產(chǎn)生OOM，但導(dǎo)入不是一個(gè)輕錢包時(shí)，則有可能產(chǎn)生OOM。例如，我們使用Imtoken創(chuàng)建一個(gè)錢包并導(dǎo)出Keystore，Keystore如下：

{"address":"9a2e2419f3af050d4730f80e7a65b9f8deb5e16f","crypto":{"cipher":"aes-128-ctr","cipherparams":{"iv":"eaccea79c27a91e307f24988186ef21a"},"ciphertext":"a163e532edf2d76beaee5c26fd2c2fab071a9cb37627aa185ac89e223e41ab97","kdf":"scrypt","kdfparams":{"dklen":32,"n":65536,"p":1,"r":8,"salt":"6a847392a029553f4152dea7bb0b6fb0ac9eec29f55e572fe94603182f5ed7f1"},"mac":"3fad2a31e18c611b10df84db9ae368ce2e189b5c35e9f111e40ca4b4bfb02491"},"id":"032c47c2-c7b7-46f8-a3f7-f526580f6f09","version":3}

{"address":"9a2e2419f3af050d4730f80e7a65b9f8deb5e16f","crypto":{"cipher":"aes-128-ctr","cipherparams":{"iv":"eaccea79c27a91e307f24988186ef21a"},"ciphertext":"a163e532edf2d76beaee5c26fd2c2fab071a9cb37627aa185ac89e223e41ab97","kdf":"scrypt","kdfparams":{"dklen":32,"n":65536,"p":1,"r":8,"salt":"6a847392a029553f4152dea7bb0b6fb0ac9eec29f55e572fe94603182f5ed7f1"},"mac":"3fad2a31e18c611b10df84db9ae368ce2e189b5c35e9f111e40ca4b4bfb02491"},"id":"032c47c2-c7b7-46f8-a3f7-f526580f6f09","version":3}

可以看到，其中n為65536，p為1，而輕錢包的n為1<<12,即2的12次方，4096，所以這不是一個(gè)輕錢包。我們將該Keystore作為一個(gè)json文件push到SD卡中，然后使用Web3j進(jìn)行導(dǎo)入：發(fā)現(xiàn)同樣會(huì)OOM：

Causedby:java.lang.OutOfMemoryError:Failedtoallocatea1036byteallocationwith13588800freebytesand12MBuntilOOM;failedduetofragmentation(requiredcontinguousfree16384bytesforanewbufferwherelargestcontiguousfree12288bytes)

atorg.spongycastle.util.Arrays.clone(Arrays.java:602)

atorg.spongycastle.crypto.generators.SCrypt.SMix(SCrypt.java:126)

atorg.spongycastle.crypto.generators.SCrypt.MFcrypt(SCrypt.java:87)

atorg.spongycastle.crypto.generators.SCrypt.generate(SCrypt.java:66)

atorg.web3j.crypto.Wallet.generateDerivedScryptKey(Wallet.java:136)

atorg.web3j.crypto.Wallet.decrypt(Wallet.java:214)

atorg.web3j.crypto.WalletUtils.loadCredentials(WalletUtils.java:112)

Causedby:java.lang.OutOfMemoryError:Failedtoallocatea1036byteallocationwith13588800freebytesand12MBuntilOOM;failedduetofragmentation(requiredcontinguousfree16384bytesforanewbufferwherelargestcontiguousfree12288bytes)

atorg.spongycastle.util.Arrays.clone(Arrays.java:602)

atorg.spongycastle.crypto.generators.SCrypt.SMix(SCrypt.java:126)

atorg.spongycastle.crypto.generators.SCrypt.MFcrypt(SCrypt.java:87)

atorg.spongycastle.crypto.generators.SCrypt.generate(SCrypt.java:66)

atorg.web3j.crypto.Wallet.generateDerivedScryptKey(Wallet.java:136)

atorg.web3j.crypto.Wallet.decrypt(Wallet.java:214)

atorg.web3j.crypto.WalletUtils.loadCredentials(WalletUtils.java:112)

通過log可以看出來，這里和創(chuàng)建錢包的OOM是一樣的，都是最后調(diào)用generateDerivedScryptKey后導(dǎo)致:創(chuàng)建錢包可以創(chuàng)建一