285 lines
7.1 KiB
Go
285 lines
7.1 KiB
Go
package router
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// download from https://raw.githubusercontent.com/grpc-ecosystem/grpc-gateway/master/runtime/pattern.go
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import (
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"context"
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"errors"
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"fmt"
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"strings"
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"github.com/unistack-org/micro/v3/logger"
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)
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var (
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// ErrNotMatch indicates that the given HTTP request path does not match to the pattern.
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ErrNotMatch = errors.New("not match to the path pattern")
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// ErrInvalidPattern indicates that the given definition of Pattern is not valid.
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ErrInvalidPattern = errors.New("invalid pattern")
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)
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type rop struct {
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code OpCode
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operand int
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}
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// Pattern is a template pattern of http request paths defined in github.com/googleapis/googleapis/google/api/http.proto.
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type Pattern struct {
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verb string
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// ops is a list of operations
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ops []rop
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// pool is a constant pool indexed by the operands or vars
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pool []string
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// vars is a list of variables names to be bound by this pattern
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vars []string
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// stacksize is the max depth of the stack
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stacksize int
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// tailLen is the length of the fixed-size segments after a deep wildcard
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tailLen int
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// assumeColonVerb indicates whether a path suffix after a final
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// colon may only be interpreted as a verb.
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assumeColonVerb bool
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}
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type patternOptions struct {
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assumeColonVerb bool
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}
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// PatternOpt is an option for creating Patterns.
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type PatternOpt func(*patternOptions)
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// NewPattern returns a new Pattern from the given definition values.
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// "ops" is a sequence of op codes. "pool" is a constant pool.
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// "verb" is the verb part of the pattern. It is empty if the pattern does not have the part.
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// "version" must be 1 for now.
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// It returns an error if the given definition is invalid.
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//nolint:gocyclo
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func NewPattern(version int, ops []int, pool []string, verb string, opts ...PatternOpt) (Pattern, error) {
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options := patternOptions{
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assumeColonVerb: true,
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}
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for _, o := range opts {
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o(&options)
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}
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if version != 1 {
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if logger.V(logger.DebugLevel) {
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logger.Debug(context.TODO(), "unsupported version: %d", version)
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}
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return Pattern{}, ErrInvalidPattern
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}
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l := len(ops)
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if l%2 != 0 {
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if logger.V(logger.DebugLevel) {
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logger.Debug(context.TODO(), "odd number of ops codes: %d", l)
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}
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return Pattern{}, ErrInvalidPattern
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}
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var (
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typedOps []rop
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stack, maxstack int
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tailLen int
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pushMSeen bool
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vars []string
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)
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for i := 0; i < l; i += 2 {
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op := rop{code: OpCode(ops[i]), operand: ops[i+1]}
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switch op.code {
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case OpNop:
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continue
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case OpPush:
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if pushMSeen {
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tailLen++
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}
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stack++
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case OpPushM:
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if pushMSeen {
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if logger.V(logger.TraceLevel) {
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logger.Trace(context.TODO(), "pushM appears twice")
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}
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return Pattern{}, ErrInvalidPattern
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}
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pushMSeen = true
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stack++
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case OpLitPush:
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if op.operand < 0 || len(pool) <= op.operand {
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if logger.V(logger.TraceLevel) {
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logger.Trace(context.TODO(), "negative literal index: %d", op.operand)
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}
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return Pattern{}, ErrInvalidPattern
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}
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if pushMSeen {
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tailLen++
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}
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stack++
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case OpConcatN:
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if op.operand <= 0 {
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if logger.V(logger.TraceLevel) {
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logger.Trace(context.TODO(), "negative concat size: %d", op.operand)
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}
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return Pattern{}, ErrInvalidPattern
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}
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stack -= op.operand
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if stack < 0 {
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if logger.V(logger.TraceLevel) {
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logger.Trace(context.TODO(), "stack underflow")
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}
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return Pattern{}, ErrInvalidPattern
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}
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stack++
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case OpCapture:
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if op.operand < 0 || len(pool) <= op.operand {
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if logger.V(logger.TraceLevel) {
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logger.Trace(context.TODO(), "variable name index out of bound: %d", op.operand)
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}
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return Pattern{}, ErrInvalidPattern
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}
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v := pool[op.operand]
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op.operand = len(vars)
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vars = append(vars, v)
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stack--
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if stack < 0 {
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if logger.V(logger.DebugLevel) {
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logger.Trace(context.TODO(), "stack underflow")
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}
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return Pattern{}, ErrInvalidPattern
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}
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default:
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if logger.V(logger.DebugLevel) {
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logger.Trace(context.TODO(), "invalid opcode: %d", op.code)
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}
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return Pattern{}, ErrInvalidPattern
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}
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if maxstack < stack {
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maxstack = stack
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}
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typedOps = append(typedOps, op)
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}
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return Pattern{
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ops: typedOps,
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pool: pool,
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vars: vars,
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stacksize: maxstack,
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tailLen: tailLen,
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verb: verb,
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assumeColonVerb: options.assumeColonVerb,
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}, nil
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}
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// MustPattern is a helper function which makes it easier to call NewPattern in variable initialization.
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func MustPattern(p Pattern, err error) Pattern {
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if err != nil {
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if logger.V(logger.FatalLevel) {
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logger.Fatal(context.TODO(), "Pattern initialization failed: %v", err)
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}
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}
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return p
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}
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// Match examines components if it matches to the Pattern.
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// If it matches, the function returns a mapping from field paths to their captured values.
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// If otherwise, the function returns an error.
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//nolint:gocyclo
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func (p Pattern) Match(components []string, verb string) (map[string]string, error) {
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if p.verb != verb {
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if p.assumeColonVerb || p.verb != "" {
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return nil, ErrNotMatch
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}
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if len(components) == 0 {
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components = []string{":" + verb}
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} else {
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components = append([]string{}, components...)
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components[len(components)-1] += ":" + verb
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}
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}
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var pos int
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stack := make([]string, 0, p.stacksize)
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captured := make([]string, len(p.vars))
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l := len(components)
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for _, op := range p.ops {
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switch op.code {
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case OpNop:
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continue
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case OpPush, OpLitPush:
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if pos >= l {
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return nil, ErrNotMatch
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}
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c := components[pos]
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if op.code == OpLitPush {
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if lit := p.pool[op.operand]; c != lit {
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return nil, ErrNotMatch
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}
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}
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stack = append(stack, c)
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pos++
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case OpPushM:
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end := len(components)
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if end < pos+p.tailLen {
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return nil, ErrNotMatch
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}
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end -= p.tailLen
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stack = append(stack, strings.Join(components[pos:end], "/"))
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pos = end
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case OpConcatN:
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n := op.operand
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l := len(stack) - n
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stack = append(stack[:l], strings.Join(stack[l:], "/"))
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case OpCapture:
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n := len(stack) - 1
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captured[op.operand] = stack[n]
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stack = stack[:n]
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}
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}
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if pos < l {
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return nil, ErrNotMatch
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}
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bindings := make(map[string]string, len(captured))
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for i, val := range captured {
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bindings[p.vars[i]] = val
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}
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return bindings, nil
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}
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// Verb returns the verb part of the Pattern.
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func (p Pattern) Verb() string { return p.verb }
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func (p Pattern) String() string {
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var stack []string
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for _, op := range p.ops {
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switch op.code {
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case OpNop:
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continue
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case OpPush:
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stack = append(stack, "*")
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case OpLitPush:
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stack = append(stack, p.pool[op.operand])
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case OpPushM:
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stack = append(stack, "**")
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case OpConcatN:
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n := op.operand
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l := len(stack) - n
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stack = append(stack[:l], strings.Join(stack[l:], "/"))
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case OpCapture:
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n := len(stack) - 1
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stack[n] = fmt.Sprintf("{%s=%s}", p.vars[op.operand], stack[n])
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}
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}
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segs := strings.Join(stack, "/")
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if p.verb != "" {
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return fmt.Sprintf("/%s:%s", segs, p.verb)
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}
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return "/" + segs
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}
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// AssumeColonVerbOpt indicates whether a path suffix after a final
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// colon may only be interpreted as a verb.
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func AssumeColonVerbOpt(val bool) PatternOpt {
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return PatternOpt(func(o *patternOptions) {
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o.assumeColonVerb = val
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})
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}
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