inc.cs

berkeley db 4.6.21的源码。berkeley db是一个简单的数据库管理系统

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#include <sys/types.h>
#include <sys/stat.h>

#include <errno.h>
#include <stdarg.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include <db.h>

#define	MAXIMUM_RETRY	5

int add_color(DB_ENV *, DB *, char *, int);

int add_fruit(DB_ENV *a, DB *b, char *c, char *d) {
	a = NULL; b = NULL; c = NULL; d = 0;
	return (0);
}
void  db_open(DB_ENV *a, DB **b, char *c, int d) {
	a = NULL; b = NULL; c = NULL; d = 0;
}
void usage(){}
void env_open(DB_ENV **a) { a = NULL; }
void env_dir_create() {}
])
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int
main(int argc, char *argv[])
{
	extern int optind;
	DB *db_cats, *db_color, *db_fruit;
	DB_ENV *dbenv;
	int ch;
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	while ((ch = getopt(argc, argv, "")) != EOF)
		switch (ch) {
		case '?':
		default:
			usage();
		}
	argc -= optind;
	argv += optind;
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	env_dir_create();
	env_open(&dbenv);
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	/* Open database: Key is fruit class; Data is specific type. */
	db_open(dbenv, &db_fruit, "fruit", 0);
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	/* Open database: Key is a color; Data is an integer. */
	db_open(dbenv, &db_color, "color", 0);
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	/*
	 * Open database:
	 *	Key is a name; Data is: company name, cat breeds.
	 */
	db_open(dbenv, &db_cats, "cats", 1);
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	add_fruit(dbenv, db_fruit, "apple", "yellow delicious");
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	add_color(dbenv, db_color, "blue", 0);
	add_color(dbenv, db_color, "blue", 3);])
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	return (0);
}
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int
add_color(DB_ENV *dbenv, DB *dbp, char *color, int increment)
{
	DBT key, data;
	DB_TXN *tid;
	int fail, original, ret, t_ret;
	char buf[64];
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	/* Initialization. */
	memset(&key, 0, sizeof(key));
	key.data = color;
	key.size = strlen(color);
	memset(&data, 0, sizeof(data));
	data.flags = DB_DBT_MALLOC;
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	for (fail = 0;;) {
		/* Begin the transaction. */
		if ((ret = dbenv-__GT__txn_begin(dbenv, NULL, &tid, 0)) != 0) {
			dbenv-__GT__err(dbenv, ret, "DB_ENV-__GT__txn_begin");
			exit (1);
		}
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		/*
		 * Get the key.  If it exists, we increment the value.  If it
		 * doesn't exist, we create it.
		 */
		switch (ret = dbp-__GT__get(dbp, tid, &key, &data, DB_RMW)) {
		case 0:
			original = atoi(data.data);
			break;
		case DB_LOCK_DEADLOCK:
		default:
			/* Retry the operation. */
			if ((t_ret = tid-__GT__abort(tid)) != 0) {
				dbenv-__GT__err(dbenv, t_ret, "DB_TXN-__GT__abort");
				exit (1);
			}
			if (fail++ == MAXIMUM_RETRY)
				return (ret);
			continue;
		case DB_NOTFOUND:
			original = 0;
			break;
		}
		if (data.data != NULL)
			free(data.data);
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		/* Create the new data item. */
		(void)snprintf(buf, sizeof(buf), "%d", original + increment);
		data.data = buf;
		data.size = strlen(buf) + 1;
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		/* Store the new value. */
		switch (ret = dbp-__GT__put(dbp, tid, &key, &data, 0)) {
		case 0:
			/* Success: commit the change. */
			if ((ret = tid-__GT__commit(tid, 0)) != 0) {
				dbenv-__GT__err(dbenv, ret, "DB_TXN-__GT__commit");
				exit (1);
			}
			return (0);
		case DB_LOCK_DEADLOCK:
		default:
			/* Retry the operation. */
			if ((t_ret = tid-__GT__abort(tid)) != 0) {
				dbenv-__GT__err(dbenv, t_ret, "DB_TXN-__GT__abort");
				exit (1);
			}
			if (fail++ == MAXIMUM_RETRY)
				return (ret);
			break;
		}
	}
}])])