Import BSDDB 4.7.25 (as of svn r89086)
This commit is contained in:
Zachary Ware
513
examples_cxx/excxx_repquote/RepQuoteExample.cpp
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513
examples_cxx/excxx_repquote/RepQuoteExample.cpp
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@@ -0,0 +1,513 @@
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/*-
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* See the file LICENSE for redistribution information.
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*
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* Copyright (c) 2001,2008 Oracle. All rights reserved.
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*
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* $Id: RepQuoteExample.cpp 63573 2008-05-23 21:43:21Z trent.nelson $
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*/
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/*
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* In this application, we specify all communication via the command line. In
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* a real application, we would expect that information about the other sites
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* in the system would be maintained in some sort of configuration file. The
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* critical part of this interface is that we assume at startup that we can
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* find out
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* 1) what host/port we wish to listen on for connections,
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* 2) a (possibly empty) list of other sites we should attempt to connect
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* to; and
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* 3) what our Berkeley DB home environment is.
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*
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* These pieces of information are expressed by the following flags.
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* -m host:port (required; m stands for me)
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* -o host:port (optional; o stands for other; any number of these may be
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* specified)
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* -h home directory
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* -n nsites (optional; number of sites in replication group; defaults to 0
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* in which case we try to dynamically compute the number of sites in
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* the replication group)
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* -p priority (optional: defaults to 100)
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*/
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#include <iostream>
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#include <string>
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#include <sstream>
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#include <db_cxx.h>
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#include "RepConfigInfo.h"
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#include "dbc_auto.h"
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using std::cout;
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using std::cin;
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using std::cerr;
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using std::endl;
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using std::flush;
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using std::istream;
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using std::istringstream;
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using std::string;
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using std::getline;
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#define CACHESIZE (10 * 1024 * 1024)
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#define DATABASE "quote.db"
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const char *progname = "excxx_repquote";
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#include <errno.h>
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#ifdef _WIN32
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#define WIN32_LEAN_AND_MEAN
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#include <windows.h>
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extern "C" {
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extern int getopt(int, char * const *, const char *);
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extern char *optarg;
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}
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#endif
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// Struct used to store information in Db app_private field.
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typedef struct {
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bool is_master;
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} APP_DATA;
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static void log(char *);
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class RepQuoteExample {
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public:
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RepQuoteExample();
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void init(RepConfigInfo* config);
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void doloop();
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int terminate();
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static void event_callback(DbEnv * dbenv, u_int32_t which, void *info);
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private:
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// disable copy constructor.
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RepQuoteExample(const RepQuoteExample &);
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void operator = (const RepQuoteExample &);
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// internal data members.
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APP_DATA app_data;
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RepConfigInfo *app_config;
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DbEnv cur_env;
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// private methods.
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void print_stocks(Db *dbp);
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void prompt();
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};
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class DbHolder {
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public:
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DbHolder(DbEnv *env) : env(env) {
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dbp = 0;
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}
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~DbHolder() {
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try {
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close();
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} catch (...) {
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// Ignore: this may mean another exception is pending
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}
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}
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bool ensure_open(bool creating) {
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if (dbp)
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return (true);
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dbp = new Db(env, 0);
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dbp->set_pagesize(512);
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u_int32_t flags = DB_AUTO_COMMIT;
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if (creating)
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flags |= DB_CREATE;
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try {
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dbp->open(NULL, DATABASE, NULL, DB_BTREE, flags, 0);
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return (true);
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} catch (DbDeadlockException e) {
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} catch (DbRepHandleDeadException e) {
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} catch (DbException e) {
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if (e.get_errno() == DB_REP_LOCKOUT) {
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// Just fall through.
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} else if (e.get_errno() == ENOENT && !creating) {
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// Provide a bit of extra explanation.
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//
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log("Stock DB does not yet exist");
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} else
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throw;
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}
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// (All retryable errors fall through to here.)
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//
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log("please retry the operation");
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close();
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return (false);
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}
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void close() {
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if (dbp) {
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try {
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dbp->close(0);
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delete dbp;
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dbp = 0;
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} catch (...) {
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delete dbp;
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dbp = 0;
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throw;
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}
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}
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}
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operator Db *() {
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return dbp;
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}
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Db *operator->() {
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return dbp;
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}
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private:
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Db *dbp;
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DbEnv *env;
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};
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class StringDbt : public Dbt {
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public:
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#define GET_STRING_OK 0
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#define GET_STRING_INVALID_PARAM 1
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#define GET_STRING_SMALL_BUFFER 2
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#define GET_STRING_EMPTY_DATA 3
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int get_string(char **buf, size_t buf_len)
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{
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size_t copy_len;
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int ret = GET_STRING_OK;
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if (buf == NULL) {
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cerr << "Invalid input buffer to get_string" << endl;
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return GET_STRING_INVALID_PARAM;
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}
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// make sure the string is null terminated.
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memset(*buf, 0, buf_len);
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// if there is no string, just return.
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if (get_data() == NULL || get_size() == 0)
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return GET_STRING_OK;
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if (get_size() >= buf_len) {
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ret = GET_STRING_SMALL_BUFFER;
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copy_len = buf_len - 1; // save room for a terminator.
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} else
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copy_len = get_size();
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memcpy(*buf, get_data(), copy_len);
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return ret;
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}
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size_t get_string_length()
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{
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if (get_size() == 0)
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return 0;
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return strlen((char *)get_data());
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}
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void set_string(char *string)
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{
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set_data(string);
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set_size((u_int32_t)strlen(string));
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}
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StringDbt(char *string) :
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Dbt(string, (u_int32_t)strlen(string)) {};
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StringDbt() : Dbt() {};
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~StringDbt() {};
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// Don't add extra data to this sub-class since we want it to remain
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// compatible with Dbt objects created internally by Berkeley DB.
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};
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RepQuoteExample::RepQuoteExample() : app_config(0), cur_env(0) {
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app_data.is_master = 0; // assume I start out as client
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}
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void RepQuoteExample::init(RepConfigInfo *config) {
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app_config = config;
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cur_env.set_app_private(&app_data);
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cur_env.set_errfile(stderr);
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cur_env.set_errpfx(progname);
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cur_env.set_event_notify(event_callback);
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cur_env.repmgr_set_ack_policy(DB_REPMGR_ACKS_ALL);
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cur_env.repmgr_set_local_site(app_config->this_host.host,
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app_config->this_host.port, 0);
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for ( REP_HOST_INFO *cur = app_config->other_hosts; cur != NULL;
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cur = cur->next) {
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cur_env.repmgr_add_remote_site(cur->host, cur->port,
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NULL, cur->peer ? DB_REPMGR_PEER : 0);
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}
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if (app_config->totalsites > 0)
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cur_env.rep_set_nsites(app_config->totalsites);
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cur_env.rep_set_priority(app_config->priority);
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/*
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* We can now open our environment, although we're not ready to
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* begin replicating. However, we want to have a dbenv around
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* so that we can send it into any of our message handlers.
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*/
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cur_env.set_cachesize(0, CACHESIZE, 0);
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cur_env.set_flags(DB_TXN_NOSYNC, 1);
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cur_env.open(app_config->home, DB_CREATE | DB_RECOVER |
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DB_THREAD | DB_INIT_REP | DB_INIT_LOCK | DB_INIT_LOG |
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DB_INIT_MPOOL | DB_INIT_TXN, 0);
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if (app_config->verbose)
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cur_env.set_verbose(DB_VERB_REPLICATION, 1);
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cur_env.repmgr_start(3, app_config->start_policy);
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}
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int RepQuoteExample::terminate() {
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try {
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/*
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* We have used the DB_TXN_NOSYNC environment flag for
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* improved performance without the usual sacrifice of
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* transactional durability, as discussed in the
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* "Transactional guarantees" page of the Reference
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* Guide: if one replication site crashes, we can
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* expect the data to exist at another site. However,
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* in case we shut down all sites gracefully, we push
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* out the end of the log here so that the most
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* recent transactions don't mysteriously disappear.
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*/
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cur_env.log_flush(NULL);
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cur_env.close(0);
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} catch (DbException dbe) {
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cout << "error closing environment: " << dbe.what() << endl;
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}
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return 0;
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}
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void RepQuoteExample::prompt() {
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cout << "QUOTESERVER";
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if (!app_data.is_master)
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cout << "(read-only)";
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cout << "> " << flush;
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}
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void log(char *msg) {
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cerr << msg << endl;
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}
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// Simple command-line user interface:
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// - enter "<stock symbol> <price>" to insert or update a record in the
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// database;
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// - just press Return (i.e., blank input line) to print out the contents of
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// the database;
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// - enter "quit" or "exit" to quit.
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//
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void RepQuoteExample::doloop() {
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DbHolder dbh(&cur_env);
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string input;
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while (prompt(), getline(cin, input)) {
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istringstream is(input);
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string token1, token2;
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// Read 0, 1 or 2 tokens from the input.
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//
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int count = 0;
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if (is >> token1) {
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count++;
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if (is >> token2)
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count++;
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}
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if (count == 1) {
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if (token1 == "exit" || token1 == "quit")
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break;
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else {
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log("Format: <stock> <price>");
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continue;
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}
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}
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// Here we know count is either 0 or 2, so we're about to try a
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// DB operation.
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//
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if (!dbh.ensure_open(app_data.is_master))
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continue;
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try {
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if (count == 0)
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print_stocks(dbh);
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else if (!app_data.is_master)
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log("Can't update at client");
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else {
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const char *symbol = token1.c_str();
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StringDbt key(const_cast<char*>(symbol));
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const char *price = token2.c_str();
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StringDbt data(const_cast<char*>(price));
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dbh->put(NULL, &key, &data, 0);
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}
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} catch (DbDeadlockException e) {
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log("please retry the operation");
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dbh.close();
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} catch (DbRepHandleDeadException e) {
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log("please retry the operation");
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dbh.close();
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} catch (DbException e) {
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if (e.get_errno() == DB_REP_LOCKOUT) {
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log("please retry the operation");
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dbh.close();
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} else
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throw;
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}
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}
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dbh.close();
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}
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void RepQuoteExample::event_callback(DbEnv* dbenv, u_int32_t which, void *info)
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{
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APP_DATA *app = (APP_DATA*)dbenv->get_app_private();
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info = NULL; /* Currently unused. */
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switch (which) {
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case DB_EVENT_REP_MASTER:
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app->is_master = 1;
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break;
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case DB_EVENT_REP_CLIENT:
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app->is_master = 0;
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break;
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case DB_EVENT_REP_STARTUPDONE: /* FALLTHROUGH */
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case DB_EVENT_REP_NEWMASTER:
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case DB_EVENT_REP_PERM_FAILED:
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// I don't care about this one, for now.
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break;
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default:
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dbenv->errx("ignoring event %d", which);
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}
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}
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void RepQuoteExample::print_stocks(Db *dbp) {
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StringDbt key, data;
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#define MAXKEYSIZE 10
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#define MAXDATASIZE 20
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char keybuf[MAXKEYSIZE + 1], databuf[MAXDATASIZE + 1];
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char *kbuf, *dbuf;
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memset(&key, 0, sizeof(key));
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memset(&data, 0, sizeof(data));
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kbuf = keybuf;
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dbuf = databuf;
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DbcAuto dbc(dbp, 0, 0);
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cout << "\tSymbol\tPrice" << endl
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<< "\t======\t=====" << endl;
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for (int ret = dbc->get(&key, &data, DB_FIRST);
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ret == 0;
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ret = dbc->get(&key, &data, DB_NEXT)) {
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key.get_string(&kbuf, MAXKEYSIZE);
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data.get_string(&dbuf, MAXDATASIZE);
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cout << "\t" << keybuf << "\t" << databuf << endl;
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}
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cout << endl << flush;
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dbc.close();
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}
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static void usage() {
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cerr << "usage: " << progname << endl
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<< "[-h home][-o host:port][-m host:port][-f host:port]"
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<< "[-n nsites][-p priority]" << endl;
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cerr << "\t -m host:port (required; m stands for me)" << endl
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<< "\t -o host:port (optional; o stands for other; any "
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<< "number of these may be specified)" << endl
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<< "\t -h home directory" << endl
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<< "\t -n nsites (optional; number of sites in replication "
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<< "group; defaults to 0" << endl
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<< "\t in which case we try to dynamically compute the "
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<< "number of sites in" << endl
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<< "\t the replication group)" << endl
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<< "\t -p priority (optional: defaults to 100)" << endl;
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exit(EXIT_FAILURE);
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}
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int main(int argc, char **argv) {
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RepConfigInfo config;
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char ch, *portstr, *tmphost;
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int tmpport;
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bool tmppeer;
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// Extract the command line parameters
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while ((ch = getopt(argc, argv, "Cf:h:Mm:n:o:p:v")) != EOF) {
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tmppeer = false;
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switch (ch) {
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case 'C':
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config.start_policy = DB_REP_CLIENT;
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break;
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case 'h':
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config.home = optarg;
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break;
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case 'M':
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config.start_policy = DB_REP_MASTER;
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break;
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case 'm':
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config.this_host.host = strtok(optarg, ":");
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if ((portstr = strtok(NULL, ":")) == NULL) {
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cerr << "Bad host specification." << endl;
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usage();
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}
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config.this_host.port = (unsigned short)atoi(portstr);
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config.got_listen_address = true;
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break;
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case 'n':
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config.totalsites = atoi(optarg);
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break;
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case 'f':
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tmppeer = true; // FALLTHROUGH
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case 'o':
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tmphost = strtok(optarg, ":");
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if ((portstr = strtok(NULL, ":")) == NULL) {
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cerr << "Bad host specification." << endl;
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usage();
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}
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tmpport = (unsigned short)atoi(portstr);
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config.addOtherHost(tmphost, tmpport, tmppeer);
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break;
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case 'p':
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config.priority = atoi(optarg);
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break;
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case 'v':
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config.verbose = true;
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break;
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case '?':
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default:
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usage();
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}
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}
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||||
// Error check command line.
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if ((!config.got_listen_address) || config.home == NULL)
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usage();
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RepQuoteExample runner;
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try {
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runner.init(&config);
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runner.doloop();
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||||
} catch (DbException dbe) {
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cerr << "Caught an exception during initialization or"
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||||
<< " processing: " << dbe.what() << endl;
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||||
}
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runner.terminate();
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||||
return 0;
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||||
}
|
||||
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Block a user