rhai/src/func/script.rs
2022-02-08 09:02:15 +08:00

267 lines
8.9 KiB
Rust

//! Implement script function-calling mechanism for [`Engine`].
#![cfg(not(feature = "no_function"))]
use super::call::FnCallArgs;
use crate::ast::ScriptFnDef;
use crate::eval::{EvalState, GlobalRuntimeState};
use crate::{Dynamic, Engine, Module, Position, RhaiError, RhaiResult, Scope, ERR};
use std::mem;
#[cfg(feature = "no_std")]
use std::prelude::v1::*;
impl Engine {
/// # Main Entry-Point
///
/// Call a script-defined function.
///
/// If `rewind_scope` is `false`, arguments are removed from the scope but new variables are not.
///
/// # WARNING
///
/// Function call arguments may be _consumed_ when the function requires them to be passed by value.
/// All function arguments not in the first position are always passed by value and thus consumed.
///
/// **DO NOT** reuse the argument values unless for the first `&mut` argument - all others are silently replaced by `()`!
pub(crate) fn call_script_fn(
&self,
scope: &mut Scope,
global: &mut GlobalRuntimeState,
state: &mut EvalState,
lib: &[&Module],
this_ptr: &mut Option<&mut Dynamic>,
fn_def: &ScriptFnDef,
args: &mut FnCallArgs,
rewind_scope: bool,
pos: Position,
level: usize,
) -> RhaiResult {
#[inline(never)]
fn make_error(
name: String,
fn_def: &ScriptFnDef,
global: &GlobalRuntimeState,
err: RhaiError,
pos: Position,
) -> RhaiResult {
let _fn_def = fn_def;
#[cfg(not(feature = "no_module"))]
let source = _fn_def
.environ
.as_ref()
.and_then(|environ| environ.lib.id().map(str::to_string));
#[cfg(feature = "no_module")]
let source = None;
Err(ERR::ErrorInFunctionCall(
name,
source.unwrap_or_else(|| global.source.to_string()),
err,
pos,
)
.into())
}
assert!(fn_def.params.len() == args.len());
#[cfg(not(feature = "unchecked"))]
self.inc_operations(&mut global.num_operations, pos)?;
// Check for stack overflow
#[cfg(not(feature = "unchecked"))]
if level > self.max_call_levels() {
return Err(ERR::ErrorStackOverflow(pos).into());
}
#[cfg(feature = "debugging")]
if self.debugger.is_none() && fn_def.body.is_empty() {
return Ok(Dynamic::UNIT);
}
#[cfg(not(feature = "debugging"))]
if fn_def.body.is_empty() {
return Ok(Dynamic::UNIT);
}
let orig_scope_len = scope.len();
#[cfg(not(feature = "no_module"))]
let orig_imports_len = global.num_imports();
#[cfg(feature = "debugging")]
let orig_call_stack_len = global.debugger.call_stack().len();
// Put arguments into scope as variables
scope.extend(fn_def.params.iter().cloned().zip(args.into_iter().map(|v| {
// Actually consume the arguments instead of cloning them
mem::take(*v)
})));
// Push a new call stack frame
#[cfg(feature = "debugging")]
if self.debugger.is_some() {
global.debugger.push_call_stack_frame(
fn_def.name.clone(),
scope
.iter()
.skip(orig_scope_len)
.map(|(.., v)| v.clone())
.collect(),
global.source.clone(),
pos,
);
}
// Merge in encapsulated environment, if any
let orig_fn_resolution_caches_len = state.fn_resolution_caches_len();
#[cfg(not(feature = "no_module"))]
let mut lib_merged = crate::StaticVec::with_capacity(lib.len() + 1);
#[cfg(not(feature = "no_module"))]
let (lib, constants) = if let Some(crate::ast::EncapsulatedEnviron {
lib: ref fn_lib,
ref imports,
ref constants,
}) = fn_def.environ
{
for (n, m) in imports.iter().cloned() {
global.push_import(n, m)
}
(
if fn_lib.is_empty() {
lib
} else {
state.push_fn_resolution_cache();
lib_merged.push(fn_lib.as_ref());
lib_merged.extend(lib.iter().cloned());
&lib_merged
},
Some(mem::replace(&mut global.constants, constants.clone())),
)
} else {
(lib, None)
};
#[cfg(feature = "debugging")]
{
let node = crate::ast::Stmt::Noop(fn_def.body.position());
self.run_debugger(scope, global, state, lib, this_ptr, &node, level)?;
}
// Evaluate the function
let mut _result = self
.eval_stmt_block(
scope,
global,
state,
lib,
this_ptr,
&fn_def.body,
rewind_scope,
level,
)
.or_else(|err| match *err {
// Convert return statement to return value
ERR::Return(x, ..) => Ok(x),
// Error in sub function call
ERR::ErrorInFunctionCall(name, src, err, ..) => {
let fn_name = if src.is_empty() {
format!("{} < {}", name, fn_def.name)
} else {
format!("{} @ '{}' < {}", name, src, fn_def.name)
};
make_error(fn_name, fn_def, global, err, pos)
}
// System errors are passed straight-through
mut err if err.is_system_exception() => {
err.set_position(pos);
Err(err.into())
}
// Other errors are wrapped in `ErrorInFunctionCall`
_ => make_error(fn_def.name.to_string(), fn_def, global, err, pos),
});
#[cfg(feature = "debugging")]
{
let trigger = match global.debugger.status {
crate::eval::DebuggerStatus::FunctionExit(n) => n >= level,
crate::eval::DebuggerStatus::Next(.., true) => true,
_ => false,
};
if trigger {
let node = crate::ast::Stmt::Noop(fn_def.body.end_position().or_else(pos));
let node = (&node).into();
let event = match _result {
Ok(ref r) => crate::eval::DebuggerEvent::FunctionExitWithValue(r),
Err(ref err) => crate::eval::DebuggerEvent::FunctionExitWithError(err),
};
match self.run_debugger_raw(scope, global, state, lib, this_ptr, node, event, level)
{
Ok(_) => (),
Err(err) => _result = Err(err),
}
}
// Pop the call stack
global.debugger.rewind_call_stack(orig_call_stack_len);
}
// Remove all local variables and imported modules
if rewind_scope {
scope.rewind(orig_scope_len);
} else if !args.is_empty() {
// Remove arguments only, leaving new variables in the scope
scope.remove_range(orig_scope_len, args.len())
}
#[cfg(not(feature = "no_module"))]
global.truncate_imports(orig_imports_len);
// Restore constants
#[cfg(not(feature = "no_module"))]
if let Some(constants) = constants {
global.constants = constants;
}
// Restore state
state.rewind_fn_resolution_caches(orig_fn_resolution_caches_len);
_result
}
// Does a script-defined function exist?
#[must_use]
pub(crate) fn has_script_fn(
&self,
global: Option<&GlobalRuntimeState>,
state: &mut EvalState,
lib: &[&Module],
hash_script: u64,
) -> bool {
let _global = global;
let cache = state.fn_resolution_cache_mut();
if let Some(result) = cache.get(&hash_script).map(|v| v.is_some()) {
return result;
}
// First check script-defined functions
let result = lib.iter().any(|&m| m.contains_fn(hash_script))
// Then check the global namespace and packages
|| self.global_modules.iter().any(|m| m.contains_fn(hash_script));
#[cfg(not(feature = "no_module"))]
let result = result ||
// Then check imported modules
_global.map_or(false, |m| m.contains_qualified_fn(hash_script))
// Then check sub-modules
|| self.global_sub_modules.values().any(|m| m.contains_qualified_fn(hash_script));
if !result {
cache.insert(hash_script, None);
}
result
}
}