/*-
 * Copyright (c) 2008-2012 WiredTiger, Inc.
 *	All rights reserved.
 *
 * See the file LICENSE for redistribution information.
 */

#include "wt_internal.h"

/*
 * __handle_error_default --
 *	Default WT_EVENT_HANDLER->handle_error implementation: send to stderr.
 */
static int
__handle_error_default(WT_EVENT_HANDLER *handler, int error, const char *errmsg)
{
	WT_UNUSED(handler);
	WT_UNUSED(error);

	return (fprintf(stderr, "%s\n", errmsg) >= 0 ? 0 : EIO);
}

/*
 * __handle_message_default --
 *	Default WT_EVENT_HANDLER->handle_message implementation: send to stdout.
 */
static int
__handle_message_default(WT_EVENT_HANDLER *handler, const char *message)
{
	WT_UNUSED(handler);

	return (printf("%s\n", message) >= 0 ? 0 : EIO);
}

/*
 * __handle_progress_default --
 *	Default WT_EVENT_HANDLER->handle_progress implementation: ignore.
 */
static int
__handle_progress_default(
    WT_EVENT_HANDLER *handler, const char *operation, uint64_t progress)
{
	WT_UNUSED(handler);
	WT_UNUSED(operation);
	WT_UNUSED(progress);

	return (0);
}

static WT_EVENT_HANDLER __event_handler_default = {
	__handle_error_default,
	__handle_message_default,
	__handle_progress_default
};

/*
 * __handler_failure --
 *	Report the failure of an application-configured event handler.
 */
static void
__handler_failure(WT_SESSION_IMPL *session,
    int error, const char *which, int error_handler_failed)
{
	WT_EVENT_HANDLER *handler;

	/*
	 * !!!
	 * SECURITY:
	 * Buffer placed at the end of the stack in case snprintf overflows.
	 */
	char s[256];

	(void)snprintf(s, sizeof(s),
	    "application %s event handler failed: %s",
	    which, wiredtiger_strerror(error));

	/*
	 * Use the error handler to report the failure, unless it was the error
	 * handler that failed.  If it was the error handler that failed, or a
	 * call to the error handler fails, use the default error handler.
	 */
	handler = session->event_handler;
	if (!error_handler_failed &&
	    handler->handle_error != __handle_error_default &&
	    handler->handle_error(handler, error, s) == 0)
		return;

	(void)__handle_error_default(NULL, error, s);
}

/*
 * __wt_event_handler_set --
 *	Set an event handler, fill in any NULL methods with the defaults.
 */
void
__wt_event_handler_set(WT_SESSION_IMPL *session, WT_EVENT_HANDLER *handler)
{
	if (handler == NULL)
		handler = &__event_handler_default;
	else {
		if (handler->handle_error == NULL)
			handler->handle_error = __handle_error_default;
		if (handler->handle_message == NULL)
			handler->handle_message = __handle_message_default;
		if (handler->handle_progress == NULL)
			handler->handle_progress = __handle_progress_default;
	}

	session->event_handler = handler;
}

/*
 * __eventv --
 * 	Report a message to an event handler.
 */
static int
__eventv(WT_SESSION_IMPL *session, int msg_event, int error,
    const char *file_name, int line_number, const char *fmt, va_list ap)
{
	WT_EVENT_HANDLER *handler;
	WT_DECL_RET;
	size_t len, remain, wlen;
	const char *err, *prefix1, *prefix2;
	char *end, *p;

	/*
	 * We're using a stack buffer because we want error messages no matter
	 * what, and allocating a WT_ITEM, or the memory it needs, might fail.
	 *
	 * !!!
	 * SECURITY:
	 * Buffer placed at the end of the stack in case snprintf overflows.
	 */
	char s[2048];

	p = s;
	end = s + sizeof(s);

	prefix1 = (session->btree != NULL) ? session->btree->name : NULL;
	prefix2 = session->name;

	remain = WT_PTRDIFF(end, p);
	if (prefix1 != NULL && prefix2 != NULL)
		wlen =
		    (size_t)snprintf(p, remain, "%s [%s]: ", prefix1, prefix2);
	else if (prefix1 != NULL)
		wlen = (size_t)snprintf(p, remain, "%s: ", prefix1);
	else if (prefix2 != NULL)
		wlen = (size_t)snprintf(p, remain, "%s: ", prefix2);
	else
		wlen = 0;
	p = wlen >= remain ? end : p + wlen;

	if (file_name != NULL) {
		remain = WT_PTRDIFF(end, p);
		wlen = (size_t)
		    snprintf(p, remain, "%s, %d: ", file_name, line_number);
		p = wlen >= remain ? end : p + wlen;
	}

	remain = WT_PTRDIFF(end, p);
	wlen = (size_t)vsnprintf(p, remain, fmt, ap);
	p = wlen >= remain ? end : p + wlen;

	if (error != 0) {
		/*
		 * When the engine calls __wt_err on error, it often outputs an
		 * error message including the string associated with the error
		 * it's returning.  We could change the calls to call __wt_errx,
		 * but it's simpler to not append an error string if all we are
		 * doing is duplicating an existing error string.
		 *
		 * Use strcmp to compare: both strings are nul-terminated, and
		 * we don't want to run past the end of the buffer.
		 */
		err = wiredtiger_strerror(error);
		len = strlen(err);
		if (WT_PTRDIFF(p, s) < len || strcmp(p - len, err) != 0) {
			remain = WT_PTRDIFF(end, p);
			(void)snprintf(p, remain, ": %s", err);
		}
	}

	/*
	 * If a handler fails, return the error status: if we're in the process
	 * of handling an error, any return value we provide will be ignored by
	 * our caller, our caller presumably already has an error value it will
	 * be returning.
	 *
	 * If an application-specified or default informational message handler
	 * fails, complain using the application-specified or default error
	 * handler.
	 *
	 * If an application-specified error message handler fails, complain
	 * using the default error handler.  If the default error handler fails,
	 * there's nothing to do.
	 */
	handler = session->event_handler;
	if (msg_event) {
		ret = handler->handle_message(handler, s);
		if (ret != 0)
			__handler_failure(session, ret, "message", 0);
	} else {
		ret = handler->handle_error(handler, error, s);
		if (ret != 0 && handler->handle_error != __handle_error_default)
			__handler_failure(session, ret, "error", 1);
	}

	return (ret);
}

/*
 * __wt_err --
 * 	Report an error.
 */
void
__wt_err(WT_SESSION_IMPL *session, int error, const char *fmt, ...)
    WT_GCC_FUNC_ATTRIBUTE((format (printf, 3, 4)))
{
	va_list ap;

	/*
	 * Ignore error returns from underlying event handlers, we already have
	 * an error value to return.
	 */
	va_start(ap, fmt);
	(void)__eventv(session, 0, error, NULL, 0, fmt, ap);
	va_end(ap);
}

/*
 * __wt_errx --
 * 	Report an error with no error code.
 */
void
__wt_errx(WT_SESSION_IMPL *session, const char *fmt, ...)
    WT_GCC_FUNC_ATTRIBUTE((format (printf, 2, 3)))
{
	va_list ap;

	/*
	 * Ignore error returns from underlying event handlers, we already have
	 * an error value to return.
	 */
	va_start(ap, fmt);
	(void)__eventv(session, 0, 0, NULL, 0, fmt, ap);
	va_end(ap);
}

/*
 * __wt_verrx --
 *	Interface to support the extension API.
 */
int
__wt_verrx(WT_SESSION_IMPL *session, const char *fmt, va_list ap)
{
	return (__eventv(session, 0, 0, NULL, 0, fmt, ap));
}
/*
 * __wt_msg --
 * 	Informational message.
 */
int
__wt_msg(WT_SESSION_IMPL *session, const char *fmt, ...)
    WT_GCC_FUNC_ATTRIBUTE((format (printf, 2, 3)))
{
	WT_DECL_RET;
	va_list ap;

	va_start(ap, fmt);
	ret = __wt_vmsg(session, fmt, ap);
	va_end(ap);

	return (ret);
}

/*
 * __wt_vmsg --
 * 	Informational message.
 */
int
__wt_vmsg(WT_SESSION_IMPL *session, const char *fmt, va_list ap)
{
	WT_EVENT_HANDLER *handler;

	/*
	 * !!!
	 * SECURITY:
	 * Buffer placed at the end of the stack in case snprintf overflows.
	 */
	char s[2048];

	(void)vsnprintf(s, sizeof(s), fmt, ap);

	handler = session->event_handler;
	return (handler->handle_message(handler, s));
}

/*
 * __wt_progress --
 *	Progress message.
 */
int
__wt_progress(WT_SESSION_IMPL *session, const char *s, uint64_t v)
{
	WT_DECL_RET;
	WT_EVENT_HANDLER *handler;

	handler = session->event_handler;
	if (handler != NULL && handler->handle_progress != NULL)
		if ((ret = handler->handle_progress(
		    handler, s == NULL ? session->name : s, v)) != 0)
			__handler_failure(session, ret, "progress", 0);
	return (0);
}

/*
 * __wt_verbose --
 * 	Verbose message.
 */
int
__wt_verbose(WT_SESSION_IMPL *session, const char *fmt, ...)
    WT_GCC_FUNC_ATTRIBUTE((format (printf, 2, 3)))
{
	WT_DECL_RET;
	va_list ap;

	va_start(ap, fmt);
	ret = __eventv(session, 1, 0, NULL, 0, fmt, ap);
	va_end(ap);
	return (ret);
}

/*
 * __wt_assert --
 *	Assert and other unexpected failures, includes file/line information
 * for debugging.
 */
void
__wt_assert(WT_SESSION_IMPL *session,
    int error, const char *file_name, int line_number, const char *fmt, ...)
    WT_GCC_FUNC_ATTRIBUTE((format (printf, 5, 6)))
{
	va_list ap;

	va_start(ap, fmt);
	(void)__eventv(session, 0, error, file_name, line_number, fmt, ap);
	va_end(ap);

#ifdef HAVE_DIAGNOSTIC
	__wt_abort(session);
	/* NOTREACHED */
#endif
}

/*
 * __wt_illegal_value --
 *	Print a standard error message when we detect an illegal value.
 */
int
__wt_illegal_value(WT_SESSION_IMPL *session, const char *name)
{
	WT_RET_MSG(session, WT_ERROR,
	    "%s%s"
	    "encountered an illegal file format or internal value; restart "
	    "the system and verify the underlying files, if corruption is "
	    "detected use the WT_SESSION salvage method or the wt utility's "
	    "salvage command to repair the file",
	    name == NULL ? "" : name, name == NULL ? "" : " ");
}

/*
 * __wt_unknown_object_type --
 *	Print a standard error message when given an unknown object type.
 */
int
__wt_unknown_object_type(WT_SESSION_IMPL *session, const char *uri)
{
	WT_RET_MSG(session, EINVAL,
	    "unknown or unsupported object type: %s", uri);
}