Struct serde_json_borrow::Map

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pub struct Map<'ctx>(/* private fields */);

Expand description

Represents a JSON key/value type.

For performance reasons we use a Vec instead of a Hashmap. This comes with a tradeoff of slower key accesses as we need to iterate and compare.

The ObjectAsVec struct is a wrapper around a Vec of (&str, Value) pairs. It provides methods to make it easy to migrate from serde_json::Value::Object or serde_json::Map.

Implementations§

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impl<'ctx> ObjectAsVec<'ctx>

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pub fn as_vec(&self) -> &Vec<(KeyStrType<'_>, Value<'_>)>

Access to the underlying Vec.

§Note

Since KeyStrType can be changed via a feature flag avoid using as_vec and use other methods instead. This could be a problem with feature unification, when one crate uses it as &str and another uses it as Cow, both will get Cow<str?

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pub fn into_vec(self) -> Vec<(Cow<'ctx, str>, Value<'ctx>)>

Access to the underlying Vec. Keys are normalized to Cow.

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pub fn get(&self, key: &str) -> Option<&Value<'_>>

Returns a reference to the value corresponding to the key.

§Performance

As this is backed by a Vec, this searches linearly through the Vec as may be much more expensive than a Hashmap for larger Objects.

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pub fn get_mut(&mut self, key: &str) -> Option<&mut Value<'ctx>>

Returns a mutable reference to the value corresponding to the key, if it exists.

§Performance

As this is backed by a Vec, this searches linearly through the Vec as may be much more expensive than a Hashmap for larger Objects.

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pub fn get_key_value(&self, key: &str) -> Option<(&str, &Value<'_>)>

Returns the key-value pair corresponding to the supplied key.

§Performance

As this is backed by a Vec, this searches linearly through the Vec as may be much more expensive than a Hashmap for larger Objects.

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pub fn iter(&self) -> impl Iterator<Item = (&str, &Value<'_>)>

An iterator visiting all key-value pairs

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pub fn len(&self) -> usize

Returns the number of elements in the object

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pub fn is_empty(&self) -> bool

Returns true if the object contains no elements

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pub fn keys(&self) -> impl Iterator<Item = &str>

An iterator visiting all keys

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pub fn values(&self) -> impl Iterator<Item = &Value<'_>>

An iterator visiting all values

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pub fn contains_key(&self, key: &str) -> bool

Returns true if the object contains a value for the specified key.

§Performance

As this is backed by a Vec, this searches linearly through the Vec as may be much more expensive than a Hashmap for larger Objects.

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pub fn insert( &mut self, key: &'ctx str, value: Value<'ctx> ) -> Option<Value<'ctx>>

Inserts a key-value pair into the object. If the object did not have this key present, None is returned. If the object did have this key present, the value is updated, and the old value is returned.

§Performance

This operation is linear in the size of the Vec because it potentially requires iterating through all elements to find a matching key.

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pub fn insert_or_get_mut( &mut self, key: &'ctx str, value: Value<'ctx> ) -> &mut Value<'ctx>

Inserts a key-value pair into the object if the key does not yet exist, otherwise returns a mutable reference to the existing value.

§Performance

This operation might be linear in the size of the Vec because it requires iterating through all elements to find a matching key, and might add to the end if not found.

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