[tools] Add wallet inspection and modification tool

This commit adds wallet-tool, a tool for creating and interacting with
wallet files. Original implementation was by Jonas Schnelli
<dev@jonasschnelli.ch> with modifications by John Newbery
<john@johnnewbery.com>

MSVC files were provided by Chun Kuan Lee <ken2812221@gmail.com>:

build: Add MSVC project files for bitcoin-wallet-tool

src/wallet/wallettool.cpp

@@ -0,0 +1,139 @@
+// Copyright (c) 2016-2018 The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#include <base58.h>
+#include <fs.h>
+#include <interfaces/chain.h>
+#include <util/system.h>
+#include <wallet/wallet.h>
+#include <wallet/walletutil.h>
+
+namespace WalletTool {
+
+// The standard wallet deleter function blocks on the validation interface
+// queue, which doesn't exist for the bitcoin-wallet. Define our own
+// deleter here.
+static void WalletToolReleaseWallet(CWallet* wallet)
+{
+    wallet->WalletLogPrintf("Releasing wallet\n");
+    wallet->Flush();
+    delete wallet;
+}
+
+static std::shared_ptr<CWallet> CreateWallet(const std::string& name, const fs::path& path)
+{
+    if (fs::exists(path)) {
+        fprintf(stderr, "Error: File exists already\n");
+        return nullptr;
+    }
+    // dummy chain interface
+    auto chain = interfaces::MakeChain();
+    std::shared_ptr<CWallet> wallet_instance(new CWallet(*chain, WalletLocation(name), WalletDatabase::Create(path)), WalletToolReleaseWallet);
+    bool first_run = true;
+    DBErrors load_wallet_ret = wallet_instance->LoadWallet(first_run);
+    if (load_wallet_ret != DBErrors::LOAD_OK) {
+        fprintf(stderr, "Error creating %s", name.c_str());
+        return nullptr;
+    }
+
+    wallet_instance->SetMinVersion(FEATURE_HD_SPLIT);
+
+    // generate a new HD seed
+    CPubKey seed = wallet_instance->GenerateNewSeed();
+    wallet_instance->SetHDSeed(seed);
+
+    fprintf(stdout, "Topping up keypool...\n");
+    wallet_instance->TopUpKeyPool();
+    return wallet_instance;
+}
+
+static std::shared_ptr<CWallet> LoadWallet(const std::string& name, const fs::path& path)
+{
+    if (!fs::exists(path)) {
+        fprintf(stderr, "Error: Wallet files does not exist\n");
+        return nullptr;
+    }
+
+    // dummy chain interface
+    auto chain = interfaces::MakeChain();
+    std::shared_ptr<CWallet> wallet_instance(new CWallet(*chain, WalletLocation(name), WalletDatabase::Create(path)), WalletToolReleaseWallet);
+    DBErrors load_wallet_ret;
+    try {
+        bool first_run;
+        load_wallet_ret = wallet_instance->LoadWallet(first_run);
+    } catch (const std::runtime_error) {
+        fprintf(stderr, "Error loading %s. Is wallet being used by another process?\n", name.c_str());
+        return nullptr;
+    }
+
+    if (load_wallet_ret != DBErrors::LOAD_OK) {
+        wallet_instance = nullptr;
+        if (load_wallet_ret == DBErrors::CORRUPT) {
+            fprintf(stderr, "Error loading %s: Wallet corrupted", name.c_str());
+            return nullptr;
+        } else if (load_wallet_ret == DBErrors::NONCRITICAL_ERROR) {
+            fprintf(stderr, "Error reading %s! All keys read correctly, but transaction data"
+                            " or address book entries might be missing or incorrect.",
+                name.c_str());
+        } else if (load_wallet_ret == DBErrors::TOO_NEW) {
+            fprintf(stderr, "Error loading %s: Wallet requires newer version of %s",
+                name.c_str(), PACKAGE_NAME);
+            return nullptr;
+        } else if (load_wallet_ret == DBErrors::NEED_REWRITE) {
+            fprintf(stderr, "Wallet needed to be rewritten: restart %s to complete", PACKAGE_NAME);
+            return nullptr;
+        } else {
+            fprintf(stderr, "Error loading %s", name.c_str());
+            return nullptr;
+        }
+    }
+
+    return wallet_instance;
+}
+
+static void WalletShowInfo(CWallet* wallet_instance)
+{
+    // lock required because of some AssertLockHeld()
+    LOCK(wallet_instance->cs_wallet);
+
+    fprintf(stdout, "Wallet info\n===========\n");
+    fprintf(stdout, "Encrypted: %s\n", wallet_instance->IsCrypted() ? "yes" : "no");
+    fprintf(stdout, "HD (hd seed available): %s\n", wallet_instance->GetHDChain().seed_id.IsNull() ? "no" : "yes");
+    fprintf(stdout, "Keypool Size: %u\n", wallet_instance->GetKeyPoolSize());
+    fprintf(stdout, "Transactions: %zu\n", wallet_instance->mapWallet.size());
+    fprintf(stdout, "Address Book: %zu\n", wallet_instance->mapAddressBook.size());
+}
+
+bool ExecuteWalletToolFunc(const std::string& command, const std::string& name)
+{
+    fs::path path = fs::absolute(name, GetWalletDir());
+
+    if (command == "create") {
+        std::shared_ptr<CWallet> wallet_instance = CreateWallet(name, path);
+        if (wallet_instance) {
+            WalletShowInfo(wallet_instance.get());
+            wallet_instance->Flush();
+        }
+    } else if (command == "info") {
+        if (!fs::exists(path)) {
+            fprintf(stderr, "Error: no wallet file at %s\n", name.c_str());
+            return false;
+        }
+        std::string error;
+        if (!WalletBatch::VerifyEnvironment(path, error)) {
+            fprintf(stderr, "Error loading %s. Is wallet being used by other process?\n", name.c_str());
+            return false;
+        }
+        std::shared_ptr<CWallet> wallet_instance = LoadWallet(name, path);
+        if (!wallet_instance) return false;
+        WalletShowInfo(wallet_instance.get());
+        wallet_instance->Flush();
+    } else {
+        fprintf(stderr, "Invalid command: %s\n", command.c_str());
+        return false;
+    }
+
+    return true;
+}
+} // namespace WalletTool