Cannot get dynamic runtime memory usage of a compiled schema Rust struct

[yahelnachum]

After compiling a schema I would like to know how much dynamic memory is in use by the Rust SchemaNode (and any children such as Vec) struct. This would be useful for cache eviction scenarios where the cache wants to use total memory size to decide when to start evicting jsonschema-rs compiled schemas.

I don't believe static analysis functions (such as std::mem::size_of) are useful here since lower down a string pattern validator would need to know the length of the pattern and complexity to calculate the dynamic memory of the compiled pattern.

I have tried to use dynamic analysis crates/functions such as get_size and memuse but jsonschema-rs does not seem to support the correct traits to enable my programs to compile.

[yahelnachum]

Static analysis using size_of

Rust code for static analysis using size_of

assert_eq!(40, size_of::<jsonschema::Validator>());

---

Dynamic analysis using get_size

Shows that get_heap_size is not implemented on the Validator struct.

$ cargo run
   Compiling get-size v0.1.4
   Compiling hello_world v0.1.0 (/home/yahel/github/tmp/hello_world)
error[E0599]: no method named `get_heap_size` found for struct `Validator` in the current scope

src/main.rs

use serde_json::json;
use get_size::GetSize;

fn main() {
    let schema = json!({"type": "string"});
    if let Ok(validator) = jsonschema::validator_for(&schema){
        assert_eq!(40, validator.get_heap_size());
    }   
}

---

Dynamic analysis using memuse

Shows that dynamic_usage is not implemented on the Validator struct.

$ cargo run
   Compiling hello_world v0.1.0 (/home/yahel/github/tmp/hello_world)
error[E0599]: no method named `dynamic_usage` found for struct `Validator` in the current scope

src/main.rs

use serde_json::json;
use memuse::DynamicUsage;

fn main() {
    let schema = json!({"type": "string"});
    if let Ok(validator) = jsonschema::validator_for(&schema){
        assert_eq!(40, validator.dynamic_usage());
    }
}

[Stranger6667]

I am reluctant to add support for traits from these crates - they are abandoned and still won't provide correct memory usage info.

Implementing correct memory usage is not currently possible because compiled regexes are opaque. I'd suggest a custom allocator for this