cmd/size_check/sizes/sizes.go

// Copyright 2022 The Fuchsia Authors.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

package sizes

import (
	"fmt"
	"strings"
)

// BinarySizes maps component names to ComponentMetadata.
type BinarySizes map[string]*ComponentMetadata

// ComponentMetadata contains size and size budget metadata for a single
// component.
type ComponentMetadata struct {
	// Size of the component in bytes.
	Size int64

	// Budget of the component in bytes.
	Budget int64

	// Creep budget of the component in bytes.
	CreepBudget int64
}

// Parse parses a raw binary_sizes map from JSON to a structured BinarySizes
// object. Byte values are casted from float64 to int64, and ".owner" keys are
// removed as they are not meaningful to our tools.
//
// The binary_sizes schema is defined in
// https://chromium.googlesource.com/infra/gerrit-plugins/binary-size/+/HEAD/README.md.
func Parse(raw map[string]any) (BinarySizes, error) {
	casted := make(map[string]int64)
	for k, v := range raw {
		if strings.HasSuffix(k, ".owner") {
			continue
		}
		val, ok := v.(float64)
		if !ok {
			return nil, fmt.Errorf("got value of type %T but expected float64", v)
		}
		casted[k] = int64(val)
	}

	parsed := make(BinarySizes)
outerLoop:
	for k, v := range casted {
		// The binary_sizes component metadata is denoted by well-known
		// suffixes. We want to group by components only, not metadata, so
		// filter out any entries with the well-known suffixes.
		for _, suffix := range []string{".budget", ".creepBudget"} {
			if strings.HasSuffix(k, suffix) {
				continue outerLoop
			}
		}
		component := k
		size := v

		// Resolve budget and creep budget metadata.
		budget, ok := casted[component+".budget"]
		if !ok {
			return nil, fmt.Errorf("%s: missing budget metadata", component)
		}
		creepBudget, ok := casted[component+".creepBudget"]
		if !ok {
			return nil, fmt.Errorf("%s: missing creep budget metadata", component)
		}
		parsed[component] = &ComponentMetadata{
			Size:        size,
			Budget:      budget,
			CreepBudget: creepBudget,
		}
	}

	return parsed, nil
}