feat(preserve_order): integrate IndexMap support across Value types and deserializers

Author: lmmx

Cargo.toml

@@ -14,7 +14,7 @@ rust-version = "1.88"
 [dependencies]
 simdutf8 = { version = "0.1.4", features = ["public_imp", "aarch64_neon"] }
 
-value-trait = { version = "0.12" }
+value-trait = { version = "0.12.1" }
 beef = { version = "0.5", optional = true }
 halfbrown = "0.4"
 # ahash known key
@@ -25,6 +25,9 @@ ahash = { version = "0.8", optional = true }
 serde = { version = "1", features = ["derive"], optional = true }
 serde_json = { version = "1", optional = true }
 
+# preserve insertion order
+indexmap = { version = "2.0", optional = true }
+
 # perf testing
 alloc_counter = { version = "0.0.4", optional = true }
 colored = { version = "3.0", optional = true }
@@ -62,6 +65,9 @@ default = ["swar-number-parsing", "serde_impl", "runtime-detection"]
 
 arraybackend = ["halfbrown/arraybackend"]
 
+# preserve insertion order
+preserve_order = ["dep:indexmap", "value-trait/indexmap"]
+
 # Forces the `owned::Value` and `borrowed::Value` to deduplicate duplicated keys by letting consecutive keys overwrite previous ones. This comes at a
 # performance cost. By default duplicate keys will not be overwritten and feeding json objects with duplicated
 # keys to either of the `Value`s will result in undefined behavior.

src/serde/value/borrowed.rs

@@ -1,5 +1,7 @@
 mod de;
 mod se;
+#[cfg(feature = "preserve_order")]
+pub mod ordered;
 
 use crate::{BorrowedValue, Result};
 use serde_ext::de::Deserialize;

src/serde/value/borrowed/de.rs

@@ -220,6 +220,7 @@ struct ObjectRefAccess<'de> {
     i: halfbrown::Iter<'de, Cow<'de, str>, Value<'de>>,
     v: Option<&'de Value<'de>>,
 }
+
 impl<'de> ObjectRefAccess<'de> {
     fn new(i: halfbrown::Iter<'de, Cow<'de, str>, Value<'de>>) -> Self {
         Self { i, v: None }

src/serde/value/borrowed/ordered.rs

@@ -0,0 +1,2 @@
+mod de;
+// mod se;