v2ray-core/common/strmatcher/strmatcher.go

package strmatcher

// Type is the type of the matcher.
type Type byte

const (
	// Full is the type of matcher that the input string must exactly equal to the pattern.
	Full Type = 0
	// Domain is the type of matcher that the input string must be a sub-domain or itself of the pattern.
	Domain Type = 1
	// Substr is the type of matcher that the input string must contain the pattern as a sub-string.
	Substr Type = 2
	// Regex is the type of matcher that the input string must matches the regular-expression pattern.
	Regex Type = 3
)

// Matcher is the interface to determine a string matches a pattern.
//   - This is a basic matcher to represent a certain kind of match semantic(full, substr, domain or regex).
type Matcher interface {
	// Type returns the matcher's type.
	Type() Type

	// Pattern returns the matcher's raw string representation.
	Pattern() string

	// String returns a string representation of the matcher containing its type and pattern.
	String() string

	// Match returns true if the given string matches a predefined pattern.
	//   * This method is seldom used for performance reason
	//     and is generally taken over by their corresponding MatcherGroup.
	Match(input string) bool
}

// MatcherGroup is an advanced type of matcher to accept a bunch of basic Matchers (of certain type, not all matcher types).
// For example:
//   - FullMatcherGroup accepts FullMatcher and uses a hash table to facilitate lookup.
//   - DomainMatcherGroup accepts DomainMatcher and uses a trie to optimize both memory consumption and lookup speed.
type MatcherGroup interface {
	// Match returns all matched matchers with their corresponding values.
	Match(input string) []uint32

	// MatchAny returns true as soon as one matching matcher is found.
	MatchAny(input string) bool
}

// IndexMatcher is a general type of matcher thats accepts all kinds of basic matchers.
// It should:
//   - Accept all Matcher types with no exception.
//   - Optimize string matching with a combination of MatcherGroups.
//   - Obey certain priority order specification when returning matched Matchers.
type IndexMatcher interface {
	// Size returns number of matchers added to IndexMatcher.
	Size() uint32

	// Add adds a new Matcher to IndexMatcher, and returns its index. The index will never be 0.
	Add(matcher Matcher) uint32

	// Build builds the IndexMatcher to be ready for matching.
	Build() error

	// Match returns the indices of all matchers that matches the input.
	//   * Empty array is returned if no such matcher exists.
	//   * The order of returned matchers should follow priority specification.
	// Priority specification:
	//   1. Priority between matcher types: full > domain > substr > regex.
	//   2. Priority of same-priority matchers matching at same position: the early added takes precedence.
	//   3. Priority of domain matchers matching at different levels: the further matched domain takes precedence.
	//   4. Priority of substr matchers matching at different positions: the further matched substr takes precedence.
	Match(input string) []uint32

	// MatchAny returns true as soon as one matching matcher is found.
	MatchAny(input string) bool
}