go/paramtools/params.go

// Package params provides Params and ParamSet.
package paramtools

import (
	"strings"

	"go.skia.org/infra/go/util"
)

// Params is a set of key,value pairs.
type Params map[string]string

// ParamSet is a set of keys and the possible values that the keys could have. I.e.
// the []string should contain no duplicates.
type ParamSet map[string][]string

// NewParams returns the parsed structured key (see query) as Params.
//
// It presumes a valid key, i.e. something that passed query.ValidateKey.
func NewParams(key string) Params {
	ret := Params{}
	parts := strings.Split(key, ",")
	parts = parts[1 : len(parts)-1]
	for _, s := range parts {
		pair := strings.Split(s, "=")
		ret[pair[0]] = pair[1]
	}
	return ret
}

// Add adds each set of Params in order to this Params.
//
// Values in p will be overwritten.
func (p Params) Add(b ...Params) {
	for _, oneMap := range b {
		for k, v := range oneMap {
			p[k] = v
		}
	}
}

// Dup returns a copy of the Params.
func (p Params) Dup() Params {
	ret := make(Params, len(p))
	for k, v := range p {
		ret[k] = v
	}
	return ret
}

// Equal returns true if this Params equals a.
func (p Params) Equal(a Params) bool {
	if len(a) != len(p) {
		return false
	}
	// Since they are the same size we only need to check from one side, i.e.
	// compare a's values to p's values.
	for k, v := range a {
		if bv, ok := p[k]; !ok || bv != v {
			return false
		}
	}
	return true
}

// Keys returns the keys of the Params.
func (p Params) Keys() []string {
	ret := make([]string, 0, len(p))
	for v := range p {
		ret = append(ret, v)
	}

	return ret
}

// NewParamSet returns a new ParamSet initialized with the given maps of parameters.
func NewParamSet(ps ...Params) ParamSet {
	ret := ParamSet{}
	for _, onePS := range ps {
		ret.AddParams(onePS)
	}
	return ret
}

// Add the Params to this ParamSet.
func (p ParamSet) AddParams(ps Params) {
	for k, v := range ps {
		// You might be tempted to replace this with
		// sort.SearchStrings(), but that's actually slower for short
		// slices. The breakpoint seems to around 50, and since most
		// of our ParamSet lists are short that ends up being slower.
		params := p[k]
		if !util.In(v, params) {
			p[k] = append(params, v)
		}
	}
}

// AddParamsFromKey is the same as calling
//
//   paramset.AddParams(NewParams(key))
//
// but without creating the intermedite Params.
//
// It presumes a valid key, i.e. something that passed query.ValidateKey.
func (p ParamSet) AddParamsFromKey(key string) {
	parts := strings.Split(key, ",")
	parts = parts[1 : len(parts)-1]
	for _, s := range parts {
		pair := strings.Split(s, "=")
		params := p[pair[0]]
		if !util.In(pair[1], params) {
			p[pair[0]] = append(params, pair[1])
		}
	}
}

// Add the ParamSet to this ParamSet.
func (p ParamSet) AddParamSet(ps ParamSet) {
	for k, arr := range ps {
		if _, ok := p[k]; !ok {
			p[k] = append([]string{}, arr...)
		} else {
			for _, v := range arr {
				if !util.In(v, p[k]) {
					p[k] = append(p[k], v)
				}
			}
		}
	}
}

// Keys returns the keys of the ParamSet.
func (p ParamSet) Keys() []string {
	ret := make([]string, 0, len(p))
	for v := range p {
		ret = append(ret, v)
	}

	return ret
}

// Copy returns a copy of the ParamSet.
func (p ParamSet) Copy() ParamSet {
	ret := ParamSet{}
	for k, v := range p {
		newV := make([]string, len(v), len(v))
		copy(newV, v)
		ret[k] = newV
	}

	return ret
}