tremor_value/utils.rs
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// Copyright 2020-2021, The Tremor Team
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
use std::io::Write;
use value_trait::base::Writable;
use crate::Value;
/// Serialize a Value in a sorted fashion to allow equality comparing the result
///
/// # Errors
/// on IO errors
pub fn sorted_serialize(j: &Value) -> Result<Vec<u8>, std::io::Error> {
// ballpark size of a 'sensible' message
let mut w = Vec::with_capacity(512);
sorted_serialize_(j, &mut w)?;
Ok(w)
}
fn sorted_serialize_<'v, W: Write>(j: &Value<'v>, w: &mut W) -> Result<(), std::io::Error> {
match j {
Value::Static(_) | Value::String(_) | Value::Bytes(_) => {
write!(w, "{}", j.encode())?;
}
Value::Array(a) => {
let mut iter = a.iter();
write!(w, "[")?;
if let Some(e) = iter.next() {
sorted_serialize_(e, w)?;
}
for e in iter {
write!(w, ",")?;
sorted_serialize_(e, w)?;
}
write!(w, "]")?;
}
Value::Object(o) => {
let mut v: Vec<(String, Value<'v>)> =
o.iter().map(|(k, v)| (k.to_string(), v.clone())).collect();
v.sort_by_key(|(k, _)| k.to_string());
let mut iter = v.into_iter();
write!(w, "{{")?;
if let Some((k, v)) = iter.next() {
sorted_serialize_(&Value::from(k), w)?;
write!(w, ":")?;
sorted_serialize_(&v, w)?;
}
for (k, v) in iter {
write!(w, ",")?;
sorted_serialize_(&Value::from(k), w)?;
write!(w, ":")?;
sorted_serialize_(&v, w)?;
}
write!(w, "}}")?;
}
}
Ok(())
}