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//! Provides a dynamic value type abstraction.
//!
//! This module gives access to a dynamically typed value which is used by
//! the template engine during execution.
//!
//! For the most part the existence of the value type can be ignored as
//! MiniJinja will perform the necessary conversions for you. For instance
//! if you write a filter that converts a string you can directly declare the
//! filter to take a [`String`](std::string::String). However for some more
//! advanced use cases it's useful to know that this type exists.
//!
//! # Converting Values
//!
//! Values are typically created via the [`From`] trait:
//!
//! ```
//! # use minijinja::value::Value;
//! let value = Value::from(42);
//! ```
//!
//! Or via the [`FromIterator`] trait:
//!
//! ```
//! # use minijinja::value::Value;
//! // collection into a sequence
//! let value: Value = (1..10).into_iter().collect();
//!
//! // collection into a map
//! let value: Value = [("key", "value")].into_iter().collect();
//! ```
//!
//! MiniJinja will however create values via an indirection via [`serde`] when
//! a template is rendered or an expression is evaluated. This can also be
//! triggered manually by using the [`Value::from_serializable`] method:
//!
//! ```
//! # use minijinja::value::Value;
//! let value = Value::from_serializable(&[1, 2, 3]);
//! ```
//!
//! To to into the inverse directly the various [`TryFrom`](std::convert::TryFrom)
//! implementations can be used:
//!
//! ```
//! # use minijinja::value::Value;
//! use std::convert::TryFrom;
//! let v = u64::try_from(Value::from(42)).unwrap();
//! ```
//!
//! # Value Function Arguments
//!
//! [Filters](crate::filters) and [tests](crate::tests) can take values as arguments
//! but optionally also rust types directly. This conversion for function arguments
//! is performed by the [`FunctionArgs`] and related traits ([`ArgType`], [`FunctionResult`]).
//!
//! # Memory Management
//!
//! Values are immutable objects which are internally reference counted which
//! means they can be copied relatively cheaply. Special care must be taken
//! so that cycles are not created to avoid causing memory leaks.
//!
//! # HTML Escaping
//!
//! MiniJinja inherits the general desire to be clever about escaping. For this
//! prupose a value will (when auto escaping is enabled) always be escaped. To
//! prevent this behavior the [`safe`](crate::filters::safe) filter can be used
//! in the template. Outside of templates the [`Value::from_safe_string`] method
//! can be used to achieve the same result.
//!
//! # Dynamic Objects
//!
//! Values can also hold "dynamic" objects. These are objects which implement the
//! [`Object`] trait and optionally [`SeqObject`] or [`StructObject`] These can
//! be used to implement dynamic functionality such as stateful values and more.
//! Dynamic objects are internally also used to implement the special `loop`
//! variable or macros.
//!
//! To create a dynamic `Value` object, use [`Value::from_object`],
//! [`Value::from_seq_object`], [`Value::from_struct_object`] or the `From<Arc<T:
//! Object>>` implementations for `Value`:
//!
//! ```rust
//! # use std::sync::Arc;
//! # use minijinja::value::{Value, Object};
//! #[derive(Debug)]
//! struct Foo;
//!
//! # impl std::fmt::Display for Foo {
//! # fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result { Ok(()) }
//! # }
//! #
//! impl Object for Foo {
//! /* implementation */
//! }
//!
//! let value = Value::from_object(Foo);
//! let value = Value::from(Arc::new(Foo));
//! let value = Value::from(Arc::new(Foo) as Arc<dyn Object>);
//! ```
// this module is based on the content module in insta which in turn is based
// on the content module in serde::private::ser.
use std::cell::{Cell, RefCell};
use std::cmp::Ordering;
use std::collections::BTreeMap;
use std::convert::TryFrom;
use std::fmt;
use std::marker::PhantomData;
use std::sync::Arc;
use serde::ser::{Serialize, Serializer};
use crate::error::{Error, ErrorKind};
use crate::functions;
use crate::key::{Key, StaticKey};
use crate::utils::OnDrop;
use crate::value::object::{SimpleSeqObject, SimpleStructObject};
use crate::value::serialize::transform;
use crate::vm::State;
pub use crate::value::argtypes::{from_args, ArgType, FunctionArgs, FunctionResult, Kwargs, Rest};
pub use crate::value::object::{Object, ObjectKind, SeqObject, SeqObjectIter, StructObject};
mod argtypes;
#[cfg(feature = "deserialization")]
mod deserialize;
mod object;
pub(crate) mod ops;
mod serialize;
#[cfg(test)]
use similar_asserts::assert_eq;
// We use in-band signalling to roundtrip some internal values. This is
// not ideal but unfortunately there is no better system in serde today.
const VALUE_HANDLE_MARKER: &str = "\x01__minijinja_ValueHandle";
#[cfg(feature = "preserve_order")]
pub(crate) type ValueMap = indexmap::IndexMap<StaticKey, Value>;
#[cfg(not(feature = "preserve_order"))]
pub(crate) type ValueMap = std::collections::BTreeMap<StaticKey, Value>;
#[inline(always)]
pub(crate) fn value_map_with_capacity(capacity: usize) -> ValueMap {
#[cfg(not(feature = "preserve_order"))]
{
let _ = capacity;
ValueMap::new()
}
#[cfg(feature = "preserve_order")]
{
ValueMap::with_capacity(capacity)
}
}
thread_local! {
static INTERNAL_SERIALIZATION: Cell<bool> = Cell::new(false);
// This should be an AtomicU64 but sadly 32bit targets do not necessarily have
// AtomicU64 available.
static LAST_VALUE_HANDLE: Cell<u32> = Cell::new(0);
static VALUE_HANDLES: RefCell<BTreeMap<u32, Value>> = RefCell::new(BTreeMap::new());
}
/// Function that returns true when serialization for [`Value`] is taking place.
///
/// MiniJinja internally creates [`Value`] objects from all values passed to the
/// engine. It does this by going through the regular serde serialization trait.
/// In some cases users might want to customize the serialization specifically for
/// MiniJinja because they want to tune the object for the template engine
/// independently of what is normally serialized to disk.
///
/// This function returns `true` when MiniJinja is serializing to [`Value`] and
/// `false` otherwise. You can call this within your own [`Serialize`]
/// implementation to change the output format.
///
/// This is particularly useful as serialization for MiniJinja does not need to
/// support deserialization. So it becomes possible to completely change what
/// gets sent there, even at the cost of serializing something that cannot be
/// deserialized.
pub fn serializing_for_value() -> bool {
INTERNAL_SERIALIZATION.with(|flag| flag.get())
}
/// When key interning is enabled while the returned token is held keys are
/// interned in a map, freed at the end of the section.
#[cfg(feature = "key_interning")]
pub(crate) use crate::key::key_interning::use_string_cache as value_optimization;
/// Without key interning this is a dummy drop.
#[cfg(not(feature = "key_interning"))]
#[inline(always)]
pub(crate) fn value_optimization() -> impl Drop {
OnDrop::new(|| {})
}
fn mark_internal_serialization() -> impl Drop {
let old = INTERNAL_SERIALIZATION.with(|flag| {
let old = flag.get();
flag.set(true);
old
});
OnDrop::new(move || {
if !old {
INTERNAL_SERIALIZATION.with(|flag| flag.set(false));
}
})
}
/// Describes the kind of value.
#[derive(Copy, Clone, Debug, Eq, PartialEq, Ord, PartialOrd)]
pub enum ValueKind {
/// The value is undefined
Undefined,
/// The value is the none singleton ([`()`])
None,
/// The value is a [`bool`]
Bool,
/// The value is a number of a supported type.
Number,
/// The value is a character.
Char,
/// The value is a string.
String,
/// The value is a byte array.
Bytes,
/// The value is an array of other values.
Seq,
/// The value is a key/value mapping.
Map,
}
impl fmt::Display for ValueKind {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
let ty = match *self {
ValueKind::Undefined => "undefined",
ValueKind::None => "none",
ValueKind::Bool => "bool",
ValueKind::Number => "number",
ValueKind::Char => "char",
ValueKind::String => "string",
ValueKind::Bytes => "bytes",
ValueKind::Seq => "sequence",
ValueKind::Map => "map",
};
write!(f, "{ty}")
}
}
/// The type of map
#[derive(Copy, Clone, Debug)]
pub(crate) enum MapType {
/// A regular map
Normal,
/// A map representing keyword arguments
Kwargs,
}
/// Type type of string
#[derive(Copy, Clone, Debug)]
pub(crate) enum StringType {
Normal,
Safe,
}
/// Wraps an internal copyable value but marks it as packed.
///
/// This is used for `i128`/`u128` in the value repr to avoid
/// the excessive 16 byte alignment.
#[derive(Copy)]
#[repr(packed)]
pub(crate) struct Packed<T: Copy>(pub T);
impl<T: Copy> Clone for Packed<T> {
fn clone(&self) -> Self {
Self(self.0)
}
}
#[derive(Clone)]
pub(crate) enum ValueRepr {
Undefined,
Bool(bool),
U64(u64),
I64(i64),
F64(f64),
Char(char),
None,
Invalid(Arc<String>),
U128(Packed<u128>),
I128(Packed<i128>),
String(Arc<String>, StringType),
Bytes(Arc<Vec<u8>>),
Seq(Arc<Vec<Value>>),
Map(Arc<ValueMap>, MapType),
Dynamic(Arc<dyn Object>),
}
impl fmt::Debug for ValueRepr {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
match self {
ValueRepr::Undefined => write!(f, "Undefined"),
ValueRepr::Bool(val) => fmt::Debug::fmt(val, f),
ValueRepr::U64(val) => fmt::Debug::fmt(val, f),
ValueRepr::I64(val) => fmt::Debug::fmt(val, f),
ValueRepr::F64(val) => fmt::Debug::fmt(val, f),
ValueRepr::Char(val) => fmt::Debug::fmt(val, f),
ValueRepr::None => write!(f, "None"),
ValueRepr::Invalid(ref val) => write!(f, "<invalid value: {}>", val),
ValueRepr::U128(val) => fmt::Debug::fmt(&{ val.0 }, f),
ValueRepr::I128(val) => fmt::Debug::fmt(&{ val.0 }, f),
ValueRepr::String(val, _) => fmt::Debug::fmt(val, f),
ValueRepr::Bytes(val) => fmt::Debug::fmt(val, f),
ValueRepr::Seq(val) => fmt::Debug::fmt(val, f),
ValueRepr::Map(val, _) => fmt::Debug::fmt(val, f),
ValueRepr::Dynamic(val) => fmt::Debug::fmt(val, f),
}
}
}
/// Represents a dynamically typed value in the template engine.
#[derive(Clone)]
pub struct Value(pub(crate) ValueRepr);
impl PartialEq for Value {
fn eq(&self, other: &Self) -> bool {
match (&self.0, &other.0) {
(ValueRepr::None, ValueRepr::None) => true,
(ValueRepr::Undefined, ValueRepr::Undefined) => true,
(ValueRepr::String(ref a, _), ValueRepr::String(ref b, _)) => a == b,
(ValueRepr::Bytes(a), ValueRepr::Bytes(b)) => a == b,
_ => match ops::coerce(self, other) {
Some(ops::CoerceResult::F64(a, b)) => a == b,
Some(ops::CoerceResult::I128(a, b)) => a == b,
Some(ops::CoerceResult::Str(a, b)) => a == b,
None => {
if let (Some(a), Some(b)) = (self.as_seq(), other.as_seq()) {
a.iter().eq(b.iter())
} else {
false
}
}
},
}
}
}
impl Eq for Value {}
impl PartialOrd for Value {
fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
match (&self.0, &other.0) {
(ValueRepr::None, ValueRepr::None) => Some(Ordering::Equal),
(ValueRepr::Undefined, ValueRepr::Undefined) => Some(Ordering::Equal),
(ValueRepr::Bytes(a), ValueRepr::Bytes(b)) => a.partial_cmp(b),
_ => match ops::coerce(self, other) {
Some(ops::CoerceResult::F64(a, b)) => a.partial_cmp(&b),
Some(ops::CoerceResult::I128(a, b)) => a.partial_cmp(&b),
Some(ops::CoerceResult::Str(a, b)) => a.partial_cmp(b),
None => None,
},
}
}
}
impl fmt::Debug for Value {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> Result<(), std::fmt::Error> {
fmt::Debug::fmt(&self.0, f)
}
}
impl fmt::Display for Value {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
match &self.0 {
ValueRepr::Undefined => Ok(()),
ValueRepr::Bool(val) => write!(f, "{val}"),
ValueRepr::U64(val) => write!(f, "{val}"),
ValueRepr::I64(val) => write!(f, "{val}"),
ValueRepr::F64(val) => {
if val.is_nan() {
write!(f, "NaN")
} else if val.is_infinite() {
write!(f, "{}inf", if val.is_sign_negative() { "-" } else { "" })
} else {
let mut num = val.to_string();
if !num.contains('.') {
num.push_str(".0");
}
write!(f, "{num}")
}
}
ValueRepr::Char(val) => write!(f, "{val}"),
ValueRepr::None => write!(f, "none"),
ValueRepr::Invalid(ref val) => write!(f, "<invalid value: {}>", val),
ValueRepr::I128(val) => write!(f, "{}", { val.0 }),
ValueRepr::String(val, _) => write!(f, "{val}"),
ValueRepr::Bytes(val) => write!(f, "{}", String::from_utf8_lossy(val)),
ValueRepr::Seq(values) => {
ok!(write!(f, "["));
for (idx, val) in values.iter().enumerate() {
if idx > 0 {
ok!(write!(f, ", "));
}
ok!(write!(f, "{val:?}"));
}
write!(f, "]")
}
ValueRepr::Map(m, _) => {
ok!(write!(f, "{{"));
for (idx, (key, val)) in m.iter().enumerate() {
if idx > 0 {
ok!(write!(f, ", "));
}
ok!(write!(f, "{key:?}: {val:?}"));
}
write!(f, "}}")
}
ValueRepr::U128(val) => write!(f, "{}", { val.0 }),
ValueRepr::Dynamic(x) => write!(f, "{x}"),
}
}
}
impl Default for Value {
fn default() -> Value {
ValueRepr::Undefined.into()
}
}
/// Intern a string.
///
/// When the `key_interning` feature is in used, then MiniJinja will attempt to
/// reuse strings in certain cases. This function can be used to utilize the
/// same functionality. There is no guarantee that a string will be interned
/// as there are heuristics involved for it. Additionally the string interning
/// will only work during the template engine execution (eg: within filters etc.).
///
/// ```
/// use minijinja::value::{intern, Value};
/// let val = Value::from(intern("my_key"));
/// ```
pub fn intern(s: &str) -> Arc<String> {
if let Key::String(ref s) = Key::make_string_key(s) {
s.clone()
} else {
unreachable!()
}
}
#[allow(clippy::len_without_is_empty)]
impl Value {
/// The undefined value
pub const UNDEFINED: Value = Value(ValueRepr::Undefined);
/// Creates a value from something that can be serialized.
///
/// This is the method that MiniJinja will generally use whenever a serializable
/// object is passed to one of the APIs that internally want to create a value.
/// For instance this is what [`context!`](crate::context) and
/// [`render`](crate::Template::render) will use.
///
/// During serialization of the value, [`serializing_for_value`] will return
/// `true` which makes it possible to customize serialization for MiniJinja.
/// For more information see [`serializing_for_value`].
///
/// ```
/// # use minijinja::value::Value;
/// let val = Value::from_serializable(&vec![1, 2, 3]);
/// ```
///
/// This method does not fail but it might return a value that is not valid. Such
/// values will when operated on fail in the template engine in most situations.
/// This for instance can happen if the underlying implementation of [`Serialize`]
/// fails. There are also cases where invalid objects are silently hidden in the
/// engine today. This is for instance the case for when keys are used in hash maps
/// that the engine cannot deal with. Invalid values are considered an implementation
/// detail. There is currently no API to validate a value.
pub fn from_serializable<T: Serialize>(value: &T) -> Value {
let _serialization_guard = mark_internal_serialization();
let _optimization_guard = value_optimization();
transform(value)
}
/// Creates a value from a safe string.
///
/// A safe string is one that will bypass auto escaping. For instance if you
/// want to have the template engine render some HTML without the user having to
/// supply the `|safe` filter, you can use a value of this type instead.
///
/// ```
/// # use minijinja::value::Value;
/// let val = Value::from_safe_string("<em>note</em>".into());
/// ```
pub fn from_safe_string(value: String) -> Value {
ValueRepr::String(Arc::new(value), StringType::Safe).into()
}
/// Creates a value from a dynamic object.
///
/// For more information see [`Object`].
///
/// ```rust
/// # use minijinja::value::{Value, Object};
/// use std::fmt;
///
/// #[derive(Debug)]
/// struct Thing {
/// id: usize,
/// }
///
/// impl fmt::Display for Thing {
/// fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
/// fmt::Debug::fmt(self, f)
/// }
/// }
///
/// impl Object for Thing {}
///
/// let val = Value::from_object(Thing { id: 42 });
/// ```
///
/// Objects are internally reference counted. If you want to hold on to the
/// `Arc` you can directly create the value from an arc'ed object:
///
/// ```rust
/// # use minijinja::value::{Value, Object};
/// # #[derive(Debug)]
/// # struct Thing { id: usize };
/// # impl std::fmt::Display for Thing {
/// # fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
/// # todo!();
/// # }
/// # }
/// # impl Object for Thing {}
/// use std::sync::Arc;
/// let val = Value::from(Arc::new(Thing { id: 42 }));
/// ```
pub fn from_object<T: Object>(value: T) -> Value {
Value::from(Arc::new(value) as Arc<dyn Object>)
}
/// Creates a value from an owned [`SeqObject`].
///
/// This is a simplified API for creating dynamic sequences
/// without having to implement the entire [`Object`] protocol.
///
/// **Note:** objects created this way cannot be downcasted via
/// [`downcast_object_ref`](Self::downcast_object_ref).
pub fn from_seq_object<T: SeqObject + 'static>(value: T) -> Value {
Value::from_object(SimpleSeqObject(value))
}
/// Creates a value from an owned [`StructObject`].
///
/// This is a simplified API for creating dynamic structs
/// without having to implement the entire [`Object`] protocol.
///
/// **Note:** objects created this way cannot be downcasted via
/// [`downcast_object_ref`](Self::downcast_object_ref).
pub fn from_struct_object<T: StructObject + 'static>(value: T) -> Value {
Value::from_object(SimpleStructObject(value))
}
/// Creates a callable value from a function.
///
/// ```
/// # use minijinja::value::Value;
/// let pow = Value::from_function(|a: u32| a * a);
/// ```
pub fn from_function<F, Rv, Args>(f: F) -> Value
where
// the crazy bounds here exist to enable borrowing in closures
F: functions::Function<Rv, Args>
+ for<'a> functions::Function<Rv, <Args as FunctionArgs<'a>>::Output>,
Rv: FunctionResult,
Args: for<'a> FunctionArgs<'a>,
{
functions::BoxedFunction::new(f).to_value()
}
/// Returns the kind of the value.
///
/// This can be used to determine what's in the value before trying to
/// perform operations on it.
pub fn kind(&self) -> ValueKind {
match self.0 {
ValueRepr::Undefined => ValueKind::Undefined,
ValueRepr::Bool(_) => ValueKind::Bool,
ValueRepr::U64(_) | ValueRepr::I64(_) | ValueRepr::F64(_) => ValueKind::Number,
ValueRepr::Char(_) => ValueKind::Char,
ValueRepr::None => ValueKind::None,
ValueRepr::I128(_) => ValueKind::Number,
ValueRepr::String(..) => ValueKind::String,
ValueRepr::Bytes(_) => ValueKind::Bytes,
ValueRepr::U128(_) => ValueKind::Number,
ValueRepr::Seq(_) => ValueKind::Seq,
ValueRepr::Map(..) => ValueKind::Map,
// XXX: invalid values report themselves as maps which is a lie
ValueRepr::Invalid(_) => ValueKind::Map,
ValueRepr::Dynamic(ref dy) => match dy.kind() {
// XXX: basic objects should probably not report as map
ObjectKind::Plain => ValueKind::Map,
ObjectKind::Seq(_) => ValueKind::Seq,
ObjectKind::Struct(_) => ValueKind::Map,
},
}
}
/// Returns `true` if the value is a number.
///
/// To convert a value into a primitive number, use [`TryFrom`] or [`TryInto`].
pub fn is_number(&self) -> bool {
matches!(
self.0,
ValueRepr::U64(_)
| ValueRepr::I64(_)
| ValueRepr::F64(_)
| ValueRepr::I128(_)
| ValueRepr::U128(_)
)
}
/// Returns `true` if the map represents keyword arguments.
pub fn is_kwargs(&self) -> bool {
matches!(self.0, ValueRepr::Map(_, MapType::Kwargs))
}
/// Is this value true?
pub fn is_true(&self) -> bool {
match self.0 {
ValueRepr::Bool(val) => val,
ValueRepr::U64(x) => x != 0,
ValueRepr::U128(x) => x.0 != 0,
ValueRepr::I64(x) => x != 0,
ValueRepr::I128(x) => x.0 != 0,
ValueRepr::F64(x) => x != 0.0,
ValueRepr::Char(x) => x != '\x00',
ValueRepr::String(ref x, _) => !x.is_empty(),
ValueRepr::Bytes(ref x) => !x.is_empty(),
ValueRepr::None | ValueRepr::Undefined | ValueRepr::Invalid(_) => false,
ValueRepr::Seq(ref x) => !x.is_empty(),
ValueRepr::Map(ref x, _) => !x.is_empty(),
ValueRepr::Dynamic(ref x) => match x.kind() {
ObjectKind::Plain => true,
ObjectKind::Seq(s) => s.item_count() != 0,
ObjectKind::Struct(s) => s.field_count() != 0,
},
}
}
/// Returns `true` if this value is safe.
pub fn is_safe(&self) -> bool {
matches!(&self.0, ValueRepr::String(_, StringType::Safe))
}
/// Returns `true` if this value is undefined.
pub fn is_undefined(&self) -> bool {
matches!(&self.0, ValueRepr::Undefined)
}
/// Returns `true` if this value is none.
pub fn is_none(&self) -> bool {
matches!(&self.0, ValueRepr::None)
}
/// If the value is a string, return it.
pub fn as_str(&self) -> Option<&str> {
match &self.0 {
ValueRepr::String(ref s, _) => Some(s.as_str()),
_ => None,
}
}
/// Returns the bytes of this value if they exist.
pub fn as_bytes(&self) -> Option<&[u8]> {
match &self.0 {
ValueRepr::String(ref s, _) => Some(s.as_bytes()),
ValueRepr::Bytes(ref b) => Some(&b[..]),
_ => None,
}
}
/// If the value is an object, it's returned as [`Object`].
pub fn as_object(&self) -> Option<&dyn Object> {
match self.0 {
ValueRepr::Dynamic(ref dy) => Some(&**dy as &dyn Object),
_ => None,
}
}
/// If the value is a sequence it's returned as [`SeqObject`].
pub fn as_seq(&self) -> Option<&dyn SeqObject> {
match self.0 {
ValueRepr::Seq(ref v) => return Some(&**v as &dyn SeqObject),
ValueRepr::Dynamic(ref dy) => {
if let ObjectKind::Seq(seq) = dy.kind() {
return Some(seq);
}
}
_ => {}
}
None
}
/// If the value is a struct, return it as [`StructObject`].
pub fn as_struct(&self) -> Option<&dyn StructObject> {
if let ValueRepr::Dynamic(ref dy) = self.0 {
if let ObjectKind::Struct(s) = dy.kind() {
return Some(s);
}
}
None
}
/// Returns the length of the contained value.
///
/// Values without a length will return `None`.
///
/// ```
/// # use minijinja::value::Value;
/// let seq = Value::from(vec![1, 2, 3, 4]);
/// assert_eq!(seq.len(), Some(4));
/// ```
pub fn len(&self) -> Option<usize> {
match self.0 {
ValueRepr::String(ref s, _) => Some(s.chars().count()),
ValueRepr::Map(ref items, _) => Some(items.len()),
ValueRepr::Seq(ref items) => Some(items.len()),
ValueRepr::Dynamic(ref dy) => match dy.kind() {
ObjectKind::Plain => None,
ObjectKind::Seq(s) => Some(s.item_count()),
ObjectKind::Struct(s) => Some(s.field_count()),
},
_ => None,
}
}
/// Looks up an attribute by attribute name.
///
/// This this returns [`UNDEFINED`](Self::UNDEFINED) when an invalid key is
/// resolved. An error is returned when if the value does not contain an object
/// that has attributes.
///
/// ```
/// # use minijinja::value::Value;
/// # fn test() -> Result<(), minijinja::Error> {
/// let ctx = minijinja::context! {
/// foo => "Foo"
/// };
/// let value = ctx.get_attr("foo")?;
/// assert_eq!(value.to_string(), "Foo");
/// # Ok(()) }
/// ```
pub fn get_attr(&self, key: &str) -> Result<Value, Error> {
Ok(match self.0 {
ValueRepr::Undefined => return Err(Error::from(ErrorKind::UndefinedError)),
ValueRepr::Map(ref items, _) => items.get(&Key::Str(key)).cloned(),
ValueRepr::Dynamic(ref dy) => match dy.kind() {
ObjectKind::Struct(s) => s.get_field(key),
ObjectKind::Plain | ObjectKind::Seq(_) => None,
},
_ => None,
}
.unwrap_or(Value::UNDEFINED))
}
/// Alternative lookup strategy without error handling exclusively for context
/// resolution.
///
/// The main difference is that the return value will be `None` if the value is
/// unable to look up the key rather than returning `Undefined` and errors will
/// also not be created.
pub(crate) fn get_attr_fast(&self, key: &str) -> Option<Value> {
match self.0 {
ValueRepr::Map(ref items, _) => items.get(&Key::Str(key)).cloned(),
ValueRepr::Dynamic(ref dy) => match dy.kind() {
ObjectKind::Struct(s) => s.get_field(key),
ObjectKind::Plain | ObjectKind::Seq(_) => None,
},
_ => None,
}
}
/// Looks up an index of the value.
///
/// This is a shortcut for [`get_item`](Self::get_item).
///
/// ```
/// # use minijinja::value::Value;
/// let seq = Value::from(vec![0u32, 1, 2]);
/// let value = seq.get_item_by_index(1).unwrap();
/// assert_eq!(value.try_into().ok(), Some(1));
/// ```
pub fn get_item_by_index(&self, idx: usize) -> Result<Value, Error> {
self.get_item(&Value(ValueRepr::U64(idx as _)))
}
/// Looks up an item (or attribute) by key.
///
/// This is similar to [`get_attr`](Self::get_attr) but instead of using
/// a string key this can be any key. For instance this can be used to
/// index into sequences. Like [`get_attr`](Self::get_attr) this returns
/// [`UNDEFINED`](Self::UNDEFINED) when an invalid key is looked up.
///
/// ```
/// # use minijinja::value::Value;
/// let ctx = minijinja::context! {
/// foo => "Foo",
/// };
/// let value = ctx.get_item(&Value::from("foo")).unwrap();
/// assert_eq!(value.to_string(), "Foo");
/// ```
pub fn get_item(&self, key: &Value) -> Result<Value, Error> {
if let ValueRepr::Undefined = self.0 {
Err(Error::from(ErrorKind::UndefinedError))
} else {
Ok(self.get_item_opt(key).unwrap_or(Value::UNDEFINED))
}
}
/// Iterates over the value.
///
/// Depending on the [`kind`](Self::kind) of the value the iterator
/// has a different behavior.
///
/// * [`ValueKind::Map`]: the iterator yields the keys of the map.
/// * [`ValueKind::Seq`]: the iterator yields the items in the sequence.
/// * [`ValueKind::None`] / [`ValueKind::Undefined`]: the iterator is empty.
///
/// ```
/// # use minijinja::value::Value;
/// # fn test() -> Result<(), minijinja::Error> {
/// let value = Value::from({
/// let mut m = std::collections::BTreeMap::new();
/// m.insert("foo", 42);
/// m.insert("bar", 23);
/// m
/// });
/// for key in value.try_iter()? {
/// let value = value.get_item(&key)?;
/// println!("{} = {}", key, value);
/// }
/// # Ok(()) }
/// ```
pub fn try_iter(&self) -> Result<ValueIter<'_>, Error> {
self.try_iter_owned().map(|inner| ValueIter {
_marker: PhantomData,
inner,
})
}
/// Returns some reference to the boxed object if it is of type `T`, or None if it isn’t.
///
/// This is basically the "reverse" of [`from_object`](Self::from_object). It's also
/// a shortcut for [`downcast_ref`](trait.Object.html#method.downcast_ref)
/// on the return value of [`as_object`](Self::as_object).
///
/// # Example
///
/// ```rust
/// # use minijinja::value::{Value, Object};
/// use std::fmt;
///
/// #[derive(Debug)]
/// struct Thing {
/// id: usize,
/// }
///
/// impl fmt::Display for Thing {
/// fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
/// fmt::Debug::fmt(self, f)
/// }
/// }
///
/// impl Object for Thing {}
///
/// let x_value = Value::from_object(Thing { id: 42 });
/// let thing = x_value.downcast_object_ref::<Thing>().unwrap();
/// assert_eq!(thing.id, 42);
/// ```
pub fn downcast_object_ref<T: Object>(&self) -> Option<&T> {
self.as_object().and_then(|x| x.downcast_ref())
}
pub(crate) fn get_item_opt(&self, key: &Value) -> Option<Value> {
let key = some!(Key::from_borrowed_value(key).ok());
let seq = match self.0 {
ValueRepr::Map(ref items, _) => return items.get(&key).cloned(),
ValueRepr::Seq(ref items) => &**items as &dyn SeqObject,
ValueRepr::Dynamic(ref dy) => match dy.kind() {
ObjectKind::Plain => return None,
ObjectKind::Seq(s) => s,
ObjectKind::Struct(s) => match key {
Key::String(ref key) => return s.get_field(key),
Key::Str(key) => return s.get_field(key),
_ => return None,
},
},
_ => return None,
};
if let Key::I64(idx) = key {
let idx = some!(isize::try_from(idx).ok());
let idx = if idx < 0 {
some!(seq.item_count().checked_sub(-idx as usize))
} else {
idx as usize
};
seq.get_item(idx)
} else {
None
}
}
/// Calls the value directly.
pub(crate) fn call(&self, state: &State, args: &[Value]) -> Result<Value, Error> {
if let ValueRepr::Dynamic(ref dy) = self.0 {
dy.call(state, args)
} else {
Err(Error::new(
ErrorKind::InvalidOperation,
format!("value of type {} is not callable", self.kind()),
))
}
}
/// Calls a method on the value.
pub(crate) fn call_method(
&self,
state: &State,
name: &str,
args: &[Value],
) -> Result<Value, Error> {
match self.0 {
ValueRepr::Dynamic(ref dy) => return dy.call_method(state, name, args),
ValueRepr::Map(ref map, _) => {
if let Some(value) = map.get(&Key::Str(name)) {
return value.call(state, args);
}
}
_ => {}
}
Err(Error::new(
ErrorKind::InvalidOperation,
format!("object has no method named {name}"),
))
}
pub(crate) fn try_into_key(self) -> Result<StaticKey, Error> {
match self.0 {
ValueRepr::Bool(val) => Ok(Key::Bool(val)),
ValueRepr::U64(v) => TryFrom::try_from(v)
.map(Key::I64)
.map_err(|_| ErrorKind::NonKey.into()),
ValueRepr::U128(v) => TryFrom::try_from(v.0)
.map(Key::I64)
.map_err(|_| ErrorKind::NonKey.into()),
ValueRepr::I64(v) => Ok(Key::I64(v)),
ValueRepr::I128(v) => TryFrom::try_from(v.0)
.map(Key::I64)
.map_err(|_| ErrorKind::NonKey.into()),
ValueRepr::Char(c) => Ok(Key::Char(c)),
ValueRepr::String(ref s, _) => Ok(Key::String(s.clone())),
_ => Err(ErrorKind::NonKey.into()),
}
}
/// Iterates over the value without holding a reference.
pub(crate) fn try_iter_owned(&self) -> Result<OwnedValueIterator, Error> {
let (iter_state, len) = match self.0 {
ValueRepr::None | ValueRepr::Undefined => (ValueIteratorState::Empty, 0),
ValueRepr::String(ref s, _) => (
ValueIteratorState::Chars(0, Arc::clone(s)),
s.chars().count(),
),
ValueRepr::Seq(ref seq) => (ValueIteratorState::Seq(0, Arc::clone(seq)), seq.len()),
#[cfg(feature = "preserve_order")]
ValueRepr::Map(ref items, _) => {
(ValueIteratorState::Map(0, Arc::clone(items)), items.len())
}
#[cfg(not(feature = "preserve_order"))]
ValueRepr::Map(ref items, _) => (
ValueIteratorState::Map(
items.iter().next().map(|x| x.0.clone()),
Arc::clone(items),
),
items.len(),
),
ValueRepr::Dynamic(ref obj) => {
match obj.kind() {
ObjectKind::Plain => (ValueIteratorState::Empty, 0),
ObjectKind::Seq(s) => (
ValueIteratorState::DynSeq(0, Arc::clone(obj)),
s.item_count(),
),
ObjectKind::Struct(s) => {
// the assumption is that structs don't have excessive field counts
// and that most iterations go over all fields, so creating a
// temporary vector here is acceptable.
if let Some(fields) = s.static_fields() {
(ValueIteratorState::StaticStr(0, fields), fields.len())
} else {
let attrs = s.fields();
let attr_count = attrs.len();
(ValueIteratorState::ArcStr(0, attrs), attr_count)
}
}
}
}
_ => {
return Err(Error::new(
ErrorKind::InvalidOperation,
format!("{} is not iterable", self.kind()),
))
}
};
Ok(OwnedValueIterator { iter_state, len })
}
#[cfg(feature = "builtins")]
pub(crate) fn get_path(&self, path: &str) -> Result<Value, Error> {
let mut rv = self.clone();
for part in path.split('.') {
if let Ok(num) = part.parse::<usize>() {
rv = ok!(rv.get_item_by_index(num));
} else {
rv = ok!(rv.get_attr(part));
}
}
Ok(rv)
}
}
impl Serialize for Value {
fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
where
S: Serializer,
{
// enable round tripping of values
if serializing_for_value() {
let handle = LAST_VALUE_HANDLE.with(|x| {
// we are okay with overflowing the handle here because these values only
// live for a very short period of time and it's not likely that you run out
// of an entire u32 worth of handles in a single serialization operation.
// This lets us stick the handle into a unit variant in the serde data model.
let rv = x.get().wrapping_add(1);
x.set(rv);
rv
});
VALUE_HANDLES.with(|handles| handles.borrow_mut().insert(handle, self.clone()));
return serializer.serialize_unit_variant(
VALUE_HANDLE_MARKER,
handle,
VALUE_HANDLE_MARKER,
);
}
match self.0 {
ValueRepr::Bool(b) => serializer.serialize_bool(b),
ValueRepr::U64(u) => serializer.serialize_u64(u),
ValueRepr::I64(i) => serializer.serialize_i64(i),
ValueRepr::F64(f) => serializer.serialize_f64(f),
ValueRepr::Char(c) => serializer.serialize_char(c),
ValueRepr::None | ValueRepr::Undefined | ValueRepr::Invalid(_) => {
serializer.serialize_unit()
}
ValueRepr::U128(u) => serializer.serialize_u128(u.0),
ValueRepr::I128(i) => serializer.serialize_i128(i.0),
ValueRepr::String(ref s, _) => serializer.serialize_str(s),
ValueRepr::Bytes(ref b) => serializer.serialize_bytes(b),
ValueRepr::Seq(ref elements) => elements.serialize(serializer),
ValueRepr::Map(ref entries, _) => {
use serde::ser::SerializeMap;
let mut map = ok!(serializer.serialize_map(Some(entries.len())));
for (ref k, ref v) in entries.iter() {
ok!(map.serialize_entry(k, v));
}
map.end()
}
ValueRepr::Dynamic(ref dy) => match dy.kind() {
ObjectKind::Plain => serializer.serialize_str(&dy.to_string()),
ObjectKind::Seq(s) => {
use serde::ser::SerializeSeq;
let mut seq = ok!(serializer.serialize_seq(Some(s.item_count())));
for item in s.iter() {
ok!(seq.serialize_element(&item));
}
seq.end()
}
ObjectKind::Struct(s) => {
use serde::ser::SerializeMap;
let mut map = ok!(serializer.serialize_map(None));
if let Some(fields) = s.static_fields() {
for k in fields {
let v = s.get_field(k).unwrap_or(Value::UNDEFINED);
ok!(map.serialize_entry(k, &v));
}
} else {
for k in s.fields() {
let v = s.get_field(&k).unwrap_or(Value::UNDEFINED);
ok!(map.serialize_entry(k.as_str(), &v));
}
}
map.end()
}
},
}
}
}
/// Iterates over a value.
pub struct ValueIter<'a> {
_marker: PhantomData<&'a Value>,
inner: OwnedValueIterator,
}
impl<'a> Iterator for ValueIter<'a> {
type Item = Value;
#[inline(always)]
fn next(&mut self) -> Option<Self::Item> {
self.inner.next()
}
}
pub(crate) struct OwnedValueIterator {
iter_state: ValueIteratorState,
len: usize,
}
impl Iterator for OwnedValueIterator {
type Item = Value;
fn next(&mut self) -> Option<Self::Item> {
self.iter_state.advance_state().map(|x| {
self.len -= 1;
x
})
}
fn size_hint(&self) -> (usize, Option<usize>) {
(self.len, Some(self.len))
}
}
impl ExactSizeIterator for OwnedValueIterator {}
impl fmt::Debug for OwnedValueIterator {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.debug_struct("ValueIterator").finish()
}
}
enum ValueIteratorState {
Empty,
Chars(usize, Arc<String>),
Seq(usize, Arc<Vec<Value>>),
StaticStr(usize, &'static [&'static str]),
ArcStr(usize, Vec<Arc<String>>),
DynSeq(usize, Arc<dyn Object>),
#[cfg(not(feature = "preserve_order"))]
Map(Option<StaticKey>, Arc<ValueMap>),
#[cfg(feature = "preserve_order")]
Map(usize, Arc<ValueMap>),
}
impl ValueIteratorState {
fn advance_state(&mut self) -> Option<Value> {
match self {
ValueIteratorState::Empty => None,
ValueIteratorState::Chars(offset, ref s) => {
s.as_str()[*offset..].chars().next().map(|c| {
*offset += c.len_utf8();
Value::from(c)
})
}
ValueIteratorState::Seq(idx, items) => items
.get(*idx)
.map(|x| {
*idx += 1;
x
})
.cloned(),
ValueIteratorState::StaticStr(idx, items) => items.get(*idx).map(|x| {
*idx += 1;
Value::from(intern(x))
}),
ValueIteratorState::ArcStr(idx, items) => items.get(*idx).map(|x| {
*idx += 1;
Value::from(x.clone())
}),
ValueIteratorState::DynSeq(idx, obj) => {
if let ObjectKind::Seq(seq) = obj.kind() {
seq.get_item(*idx).map(|x| {
*idx += 1;
x
})
} else {
unreachable!()
}
}
#[cfg(feature = "preserve_order")]
ValueIteratorState::Map(idx, map) => map.get_index(*idx).map(|x| {
*idx += 1;
Value::from(x.0.clone())
}),
#[cfg(not(feature = "preserve_order"))]
ValueIteratorState::Map(ptr, map) => {
if let Some(current) = ptr.take() {
let next = map.range(¤t..).nth(1).map(|x| x.0.clone());
let rv = Value::from(current);
*ptr = next;
Some(rv)
} else {
None
}
}
}
}
}
#[test]
fn test_dynamic_object_roundtrip() {
use std::sync::atomic::{self, AtomicUsize};
#[derive(Debug)]
struct X(AtomicUsize);
impl fmt::Display for X {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
write!(f, "{}", self.0.load(atomic::Ordering::Relaxed))
}
}
impl Object for X {
fn kind(&self) -> ObjectKind<'_> {
ObjectKind::Struct(self)
}
}
impl crate::value::object::StructObject for X {
fn get_field(&self, name: &str) -> Option<Value> {
match name {
"value" => Some(Value::from(self.0.load(atomic::Ordering::Relaxed))),
_ => None,
}
}
fn static_fields(&self) -> Option<&'static [&'static str]> {
Some(&["value"][..])
}
}
let x = Arc::new(X(Default::default()));
let x_value = Value::from(x.clone());
x.0.fetch_add(42, atomic::Ordering::Relaxed);
let x_clone = Value::from_serializable(&x_value);
x.0.fetch_add(23, atomic::Ordering::Relaxed);
assert_eq!(x_value.to_string(), "65");
assert_eq!(x_clone.to_string(), "65");
}
#[test]
#[cfg(target_pointer_width = "64")]
fn test_sizes() {
assert_eq!(std::mem::size_of::<Value>(), 24);
}