"""Action types"""
import sys
from abc import ABC
from enum import Enum, unique
from typing import (
TYPE_CHECKING,
cast,
)
from .._utils import logger_warning
from ..errors import ParseError
from ..generic import (
ArrayObject,
DictionaryObject,
NameObject,
NullObject,
TextStringObject,
is_null_or_none,
)
if sys.version_info >= (3, 11):
from enum import StrEnum
else:
class StrEnum(str, Enum):
def __str__(self) -> str:
return str(self.value)
if TYPE_CHECKING:
from .._page import PageObject
[docs]
@unique
class PageTrigger(StrEnum):
"""Trigger event entries in a page object's additional-actions dictionary."""
OPEN = "open"
"""Trigger an action when the page is opened."""
CLOSE = "close"
"""Trigger an action when the page is closed."""
@property
def _name_object(self) -> NameObject:
"""Returns the corresponding NameObject for the trigger."""
mapping = {
PageTrigger.OPEN: NameObject("/O"),
PageTrigger.CLOSE: NameObject("/C"),
}
return mapping[self]
[docs]
class Action(DictionaryObject, ABC):
"""An action dictionary defines the characteristics and behaviour of an action."""
def __init__(self) -> None:
super().__init__()
self[NameObject("/Type")] = NameObject("/Action")
# The next action or sequence of actions that shall be performed after the action
# represented by this dictionary. The value is either a single action dictionary
# or an array of action dictionaries that shall be performed in order.
self[NameObject("/Next")] = NullObject() # Optional
@classmethod
def _create_new(cls, page: "PageObject", trigger: PageTrigger, action: "Action") -> None:
"""
Create a new action and add it to the page.
Args:
page: The page to add the action to.
trigger: An open or close trigger.
action: The action to be done.
"""
trigger_name = trigger._name_object
if "/AA" not in page:
# Additional actions key not present
page[NameObject("/AA")] = DictionaryObject(
{trigger_name: action}
)
return
if isinstance(page["/AA"], NullObject):
page[NameObject("/AA")] = DictionaryObject()
if not isinstance(page["/AA"].get_object(), DictionaryObject):
current_type = type(page["/AA"]).__name__
if page.pdf is not None and getattr(page.pdf, "strict", False):
raise ParseError(
f"The type in a page object's additional-actions key must be a DictionaryObject: "
f"received type {current_type}."
)
logger_warning(
"The type in a page object's additional-actions key must be a DictionaryObject: "
"received type %(type)s.",
source=__name__,
type=current_type
)
return
additional_actions = cast(DictionaryObject, page["/AA"])
if is_null_or_none(additional_actions.get(trigger_name)):
additional_actions.update({trigger_name: action})
return
# The action dictionary's Next entry allows sequences of actions to be
# chained together. For example, the effect of clicking a link
# annotation with the mouse can be to play a sound, jump to a new
# page, and start up a movie. Note that the Next entry is not
# restricted to a single action but can contain an array of actions,
# each of which in turn can have a Next entry of its own.
# §12.6.2 Action dictionaries ISO 32000-2:2020
head = current = additional_actions.get(trigger_name)
if not isinstance(head, DictionaryObject):
raise ParseError(
f"The type in a page object's additional-actions key must be a DictionaryObject: "
f"received type {type(head).__name__}."
)
current = cast(DictionaryObject, current)
visited = set()
while True:
next_node = current.get("/Next", None)
if is_null_or_none(next_node):
break
if not isinstance(next_node, (ArrayObject, DictionaryObject)):
raise TypeError(
f"An action dictionary’s Next entry must be an Action dictionary "
f"or an array of Action dictionaries: received type {type(next_node).__name__}."
)
id_next = id(next_node)
if id_next in visited:
logger_warning("Detected cycle in the action tree for %(current)s", source=__name__, current=current)
break
visited.add(id_next)
if isinstance(next_node, ArrayObject):
current = next_node[-1]
else:
current = next_node
if not is_null_or_none(next_node := current.get("/Next")) and id(next_node) in visited:
logger_warning("Detected cycle in the action tree for %(current)s", source=__name__, current=current)
current[NameObject("/Next")] = action
additional_actions.update({trigger_name: head})
@classmethod
def _delete(cls, page: "PageObject", trigger: PageTrigger) -> None:
"""
Delete an action from the page.
Args:
page: The page to delete the action.
trigger: An open or close trigger.
"""
if "/AA" not in page:
return
trigger_name = trigger._name_object
additional_actions = cast(DictionaryObject, page["/AA"])
if trigger_name not in additional_actions:
return
del additional_actions[trigger_name]
if not additional_actions:
del page["/AA"]
[docs]
class JavaScript(Action):
"""
Upon invocation of an ECMAScript action, a PDF processor shall execute a
script that is written in the ECMAScript programming language. ECMAScript
extensions described in ISO/DIS 21757-1 shall also be allowed.
Args:
java_script: A text string containing the ECMAScript script to be executed.
"""
def __init__(self, java_script: str) -> None:
"""Initialize JavaScript with a string."""
super().__init__()
self[NameObject("/S")] = NameObject("/JavaScript")
self[NameObject("/JS")] = TextStringObject(java_script)