Re-implement Muuntaja as Protocol

[ikitommi]

• Fixes Re-implement Muuntaja as a Protocol #59
• Optimized negotiate-and-format-request (less hash-lookups)
• Optimized path for UTF-8 with Jsonista
• +20% better e2e throughput with middleware (Jsonista)

[miikka]

There's so much code moving around that this is pretty hard to review, but it mostly looks okay. The UTF-8 optimization makes sense to me, it should be the most common path!

[miikka]

Not sure what this is? Always return nil if for ((fast-memoize .. f) nil)?

[ikitommi]

good catch. we need to either guard against input to the memoize or handle the nil-case within it. Without this, the ((fast-memoize .. f) nil) always misses the cache ('(nil) is not found on the cache as it returns nil and the .get returns nil. Not sure why. But the execution cost goes from ~30ns to 3000ns. For cases like "no accept-header set" etc.

[miikka]

How about using .getOrDefault?

(let [cache ...
      sentinel (Object.)]
  (fn [& args]
    (let [cached (.getOrDefault cache args sentinel)]
      (if (identical? sentinel cached)
         (comment compute the value)
         cached))
      

[miikka]

All these small public functions would benefit from docstrings.

[ikitommi]

indeed.

[miikka]

Since this removes the Muuntaja record, should probably bump the version to 0.5.0 once this is merged.

[ikitommi]

thans for the review, fixed those.