It is questionable whether a library should be able to terminate an application. Any API function can signal an error (ex.: cannot allocate memory), so the engine use the termination approach with this port function.
/**
* Signal the port that jerry experienced a fatal failure from which it cannot
* recover.
*
* @param code gives the cause of the error.
*
* Note:
* Jerry expects the function not to return.
*
* Example: a libc-based port may implement this with exit() or abort(), or both.
*/
void jerry_port_fatal (jerry_fatal_code_t code);Error codes
typedef enum
{
ERR_OUT_OF_MEMORY = 10,
ERR_REF_COUNT_LIMIT = 12,
ERR_DISABLED_BYTE_CODE = 13,
ERR_FAILED_INTERNAL_ASSERTION = 120
} jerry_fatal_code_t;These are the only I/O functions jerry calls.
/**
* Jerry log levels. The levels are in severity order
* where the most serious levels come first.
*/
typedef enum
{
JERRY_LOG_LEVEL_ERROR, /**< the engine will terminate after the message is printed */
JERRY_LOG_LEVEL_WARNING, /**< a request is aborted, but the engine continues its operation */
JERRY_LOG_LEVEL_DEBUG, /**< debug messages from the engine, low volume */
JERRY_LOG_LEVEL_TRACE /**< detailed info about engine internals, potentially high volume */
} jerry_log_level_t;
/**
* Display or log a debug/error message, and sends it to the debugger client as well.
* The function should implement a printf-like interface, where the first argument
* specifies the log level and the second argument specifies a format string on how
* to stringify the rest of the parameter list.
*
* This function is only called with messages coming from the jerry engine as
* the result of some abnormal operation or describing its internal operations
* (e.g., data structure dumps or tracing info).
*
* It should be the port that decides whether error and debug messages are logged to
* the console, or saved to a database or to a file.
*
* Example: a libc-based port may implement this with vfprintf(stderr) or
* vfprintf(logfile), or both, depending on log level.
*
* Note:
* This port function is called by jerry-core when JERRY_LOGGING is
* enabled. It is also common practice though to use this function in
* application code.
*/
void jerry_port_log (jerry_log_level_t level, const char *fmt, ...);The jerry_port_print_char is currently not used by the jerry-core directly.
However, it provides a port specific way for jerry-ext components to print
information.
/**
* Print a character to stdout.
*/
void jerry_port_print_char (char c);The port API provides optional functions that can be used by the
user application to resolve modules. If no callback is provided
to jerry_module_link, the jerry_port_module_resolve function
is used for resolving modules.
/**
* Opens file with the given path and reads its source.
* @return the source of the file
*/
uint8_t *
jerry_port_read_source (const char *file_name_p, /**< file name */
size_t *out_size_p) /**< [out] read bytes */
{
// open file from given path
// return its source
} /* jerry_port_read_source */
/**
* Release the previously opened file's content.
*/
void
jerry_port_release_source (uint8_t *buffer_p) /**< buffer to free */
{
free (buffer_p);
} /* jerry_port_release_source */
/**
* Default module resolver.
*
* @return a module object if resolving is successful, an error otherwise
*/
jerry_value_t
jerry_port_module_resolve (const jerry_value_t specifier, /**< module specifier string */
const jerry_value_t referrer, /**< parent module */
void *user_p) /**< user data */
{
// Resolves a module using the specifier string. If a referrer is a module,
// and specifier is a relative path, the base path should be the directory
// part extracted from the path of the referrer module.
// The callback function of jerry_module_link may call this function
// if it cannot resolve a module. Furthermore if the callback is NULL,
// this function is used for resolving modules.
// The default implementation only resolves ECMAScript modules, and does
// not (currently) use the user data.
} /* jerry_port_module_resolve */
/**
* Release known modules.
*/
void
jerry_port_module_release (const jerry_value_t realm) /**< if this argument is object, release only those modules,
* which realm value is equal to this argument. */
{
// This function releases the known modules, forcing their reload
// when resolved again later. The released modules can be filtered
// by realms. This function is only called by user applications.
} /* jerry_port_module_release *//**
* Get local time zone adjustment, in milliseconds, for the given timestamp.
* The timestamp can be specified in either UTC or local time, depending on
* the value of is_utc. Adding the value returned from this function to
* a timestamp in UTC time should result in local time for the current time
* zone, and subtracting it from a timestamp in local time should result in
* UTC time.
*
* Ideally, this function should satisfy the stipulations applied to LocalTZA
* in section 20.3.1.7 of the ECMAScript version 9.0 spec.
*
* See Also:
* ECMA-262 v9, 20.3.1.7
*
* Note:
* This port function is called by jerry-core when
* JERRY_BUILTIN_DATE is set to 1. Otherwise this function is
* not used.
*
* @param unix_ms The unix timestamp we want an offset for, given in
* millisecond precision (could be now, in the future,
* or in the past). As with all unix timestamps, 0 refers to
* 1970-01-01, a day is exactly 86 400 000 milliseconds, and
* leap seconds cause the same second to occur twice.
* @param is_utc Is the given timestamp in UTC time? If false, it is in local
* time.
*
* @return milliseconds between local time and UTC for the given timestamp,
* if available
*. 0 if not available / we are in UTC.
*/
double jerry_port_get_local_time_zone_adjustment (double unix_ms, bool is_utc);
/**
* Get system time
*
* Note:
* This port function is called by jerry-core when
* JERRY_BUILTIN_DATE is set to 1. It is also common practice
* in application code to use this function for the initialization of the
* random number generator.
*
* @return milliseconds since Unix epoch
*/
double jerry_port_get_current_time (void);Allow user to provide external buffer for isolated engine contexts, so that user can configure the heap size at runtime and run multiple JS applications simultaneously.
/**
* Get the current context of the engine. Each port should provide its own
* implementation of this interface.
*
* Note:
* This port function is called by jerry-core when
* JERRY_EXTERNAL_CONTEXT is enabled. Otherwise this function is not
* used.
*
* @return the pointer to the engine context.
*/
struct jerry_context_t *jerry_port_get_current_context (void);/**
* Makes the process sleep for a given time.
*
* Note:
* This port function is called by jerry-core when JERRY_DEBUGGER is set to 1.
* Otherwise this function is not used.
*
* @param sleep_time milliseconds to sleep.
*/
void jerry_port_sleep (uint32_t sleep_time);This section describes a basic port implementation which was created for Unix based systems.
#include <stdlib.h>
#include "jerryscript-port.h"
/**
* Default implementation of jerry_port_fatal.
*/
void jerry_port_fatal (jerry_fatal_code_t code)
{
exit (code);
} /* jerry_port_fatal */#include <stdarg.h>
#include "jerryscript-port.h"
/**
* Provide log message implementation for the engine.
*
* Note:
* This example ignores the log level.
*/
void
jerry_port_log (jerry_log_level_t level, /**< log level */
const char *format, /**< format string */
...) /**< parameters */
{
va_list args;
va_start (args, format);
vfprintf (stderr, format, args);
va_end (args);
} /* jerry_port_log *//**
* Print a character to stdout with putchar.
*/
void
jerry_port_print_char (char c)
{
putchar (c);
} /* jerry_port_print_char */#include <time.h>
#include <sys/time.h>
#include "jerryscript-port.h"
/**
* Default implementation of jerry_port_get_local_time_zone_adjustment.
*/
double jerry_port_get_local_time_zone_adjustment (double unix_ms, /**< ms since unix epoch */
bool is_utc) /**< is the time above in UTC? */
{
struct tm tm;
time_t now = (time_t) (unix_ms / 1000);
localtime_r (&now, &tm);
if (!is_utc)
{
now -= tm.tm_gmtoff;
localtime_r (&now, &tm);
}
return ((double) tm.tm_gmtoff) * 1000;
} /* jerry_port_get_local_time_zone_adjustment */
/**
* Default implementation of jerry_port_get_current_time.
*/
double jerry_port_get_current_time (void)
{
struct timeval tv;
if (gettimeofday (&tv, NULL) != 0)
{
return 0;
}
return ((double) tv.tv_sec) * 1000.0 + ((double) tv.tv_usec) / 1000.0;
} /* jerry_port_get_current_time */#include "jerryscript-port.h"
#include "jerryscript-port-default.h"
/**
* Pointer to the current context.
* Note that it is a global variable, and is not a thread safe implementation.
*/
static jerry_context_t *current_context_p = NULL;
/**
* Set the current_context_p as the passed pointer.
*/
void
jerry_port_default_set_current_context (jerry_context_t *context_p) /**< points to the created context */
{
current_context_p = context_p;
} /* jerry_port_default_set_current_context */
/**
* Get the current context.
*
* @return the pointer to the current context
*/
jerry_context_t *
jerry_port_get_current_context (void)
{
return current_context_p;
} /* jerry_port_get_current_context */#include "jerryscript-port.h"
#include "jerryscript-port-default.h"
#ifdef HAVE_TIME_H
#include <time.h>
#elif defined (HAVE_UNISTD_H)
#include <unistd.h>
#endif /* HAVE_TIME_H */
#if defined (JERRY_DEBUGGER) && (JERRY_DEBUGGER == 1)
void jerry_port_sleep (uint32_t sleep_time)
{
#ifdef HAVE_TIME_H
nanosleep (&(const struct timespec)
{
(time_t) sleep_time / 1000, ((long int) sleep_time % 1000) * 1000000L /* Seconds, nanoseconds */
}
, NULL);
#elif defined (HAVE_UNISTD_H)
usleep ((useconds_t) sleep_time * 1000);
#endif /* HAVE_TIME_H */
(void) sleep_time;
} /* jerry_port_sleep */
#endif /* defined (JERRY_DEBUGGER) && (JERRY_DEBUGGER == 1) */