SegWit wallet support

This introduces two command line flags (-addresstype and -changetype) which control
the type of addresses/outputs created by the GUI and RPCs. Certain RPCs allow
overriding these (`getnewaddress` and `getrawchangeaddress`). Supported types
are "legacy" (P2PKH and P2SH-multisig), "p2sh-segwit" (P2SH-P2WPKH and P2SH-P2WSH-multisig),
and "bech32" (P2WPKH and P2WSH-multisig).

A few utility functions are added to the wallet to construct different address type
and to add the necessary entries to the wallet file to be compatible with earlier
versions (see `CWallet::LearnRelatedScripts`, `GetDestinationForKey`,
`GetAllDestinationsForKey`, `CWallet::AddAndGetDestinationForScript`).

1 files changed, 45 insertions, 0 deletions

diff --git a/src/wallet/wallet.h b/src/wallet/wallet.h
index e64ea2534a..4088ed1985 100644
--- a/src/wallet/wallet.h
+++ b/src/wallet/wallet.h
@@ -99,6 +99,19 @@ enum WalletFeature
     FEATURE_LATEST = FEATURE_COMPRPUBKEY // HD is optional, use FEATURE_COMPRPUBKEY as latest version
 };
 
+enum OutputType
+{
+    OUTPUT_TYPE_NONE,
+    OUTPUT_TYPE_LEGACY,
+    OUTPUT_TYPE_P2SH_SEGWIT,
+    OUTPUT_TYPE_BECH32,
+
+    OUTPUT_TYPE_DEFAULT = OUTPUT_TYPE_P2SH_SEGWIT
+};
+
+extern OutputType g_address_type;
+extern OutputType g_change_type;
+
 
 /** A key pool entry */
 class CKeyPool
@@ -1129,6 +1142,26 @@ public:
      * deadlock
      */
     void BlockUntilSyncedToCurrentChain();
+
+    /**
+     * Explicitly make the wallet learn the related scripts for outputs to the
+     * given key. This is purely to make the wallet file compatible with older
+     * software, as CBasicKeyStore automatically does this implicitly for all
+     * keys now.
+     */
+    void LearnRelatedScripts(const CPubKey& key, OutputType);
+
+    /**
+     * Same as LearnRelatedScripts, but when the OutputType is not known (and could
+     * be anything).
+     */
+    void LearnAllRelatedScripts(const CPubKey& key);
+
+    /**
+     * Get a destination of the requested type (if possible) to the specified script.
+     * This function will automatically add the necessary scripts to the wallet.
+     */
+    CTxDestination AddAndGetDestinationForScript(const CScript& script, OutputType);
 };
 
 /** A key allocated from the key pool. */
@@ -1218,4 +1251,16 @@ bool CWallet::DummySignTx(CMutableTransaction &txNew, const ContainerType &coins
     return true;
 }
 
+OutputType ParseOutputType(const std::string& str, OutputType default_type = OUTPUT_TYPE_DEFAULT);
+const std::string& FormatOutputType(OutputType type);
+
+/**
+ * Get a destination of the requested type (if possible) to the specified key.
+ * The caller must make sure LearnRelatedScripts has been called beforehand.
+ */
+CTxDestination GetDestinationForKey(const CPubKey& key, OutputType);
+
+/** Get all destinations (potentially) supported by the wallet for the given key. */
+std::vector<CTxDestination> GetAllDestinationsForKey(const CPubKey& key);
+
 #endif // BITCOIN_WALLET_WALLET_H