NewPattern returns a new Pattern from the given definition values. "ops" is a sequence of op codes. "pool" is a constant pool. "verb" is the verb part of the pattern. It is empty if the pattern does not have the part. "version" must be 1 for now. It returns an error if the given definition is invali
(version int, ops []int, pool []string, verb string)
| 51 | // "version" must be 1 for now. |
| 52 | // It returns an error if the given definition is invalid. |
| 53 | func NewPattern(version int, ops []int, pool []string, verb string) (Pattern, error) { |
| 54 | if version != 1 { |
| 55 | grpclog.Errorf("unsupported version: %d", version) |
| 56 | return Pattern{}, ErrInvalidPattern |
| 57 | } |
| 58 | |
| 59 | l := len(ops) |
| 60 | if l%2 != 0 { |
| 61 | grpclog.Errorf("odd number of ops codes: %d", l) |
| 62 | return Pattern{}, ErrInvalidPattern |
| 63 | } |
| 64 | |
| 65 | var ( |
| 66 | typedOps []op |
| 67 | stack, maxstack int |
| 68 | tailLen int |
| 69 | pushMSeen bool |
| 70 | vars []string |
| 71 | ) |
| 72 | for i := 0; i < l; i += 2 { |
| 73 | op := op{code: utilities.OpCode(ops[i]), operand: ops[i+1]} |
| 74 | switch op.code { |
| 75 | case utilities.OpNop: |
| 76 | continue |
| 77 | case utilities.OpPush: |
| 78 | if pushMSeen { |
| 79 | tailLen++ |
| 80 | } |
| 81 | stack++ |
| 82 | case utilities.OpPushM: |
| 83 | if pushMSeen { |
| 84 | grpclog.Error("pushM appears twice") |
| 85 | return Pattern{}, ErrInvalidPattern |
| 86 | } |
| 87 | pushMSeen = true |
| 88 | stack++ |
| 89 | case utilities.OpLitPush: |
| 90 | if op.operand < 0 || len(pool) <= op.operand { |
| 91 | grpclog.Errorf("negative literal index: %d", op.operand) |
| 92 | return Pattern{}, ErrInvalidPattern |
| 93 | } |
| 94 | if pushMSeen { |
| 95 | tailLen++ |
| 96 | } |
| 97 | stack++ |
| 98 | case utilities.OpConcatN: |
| 99 | if op.operand <= 0 { |
| 100 | grpclog.Errorf("negative concat size: %d", op.operand) |
| 101 | return Pattern{}, ErrInvalidPattern |
| 102 | } |
| 103 | stack -= op.operand |
| 104 | if stack < 0 { |
| 105 | grpclog.Error("stack underflow") |
| 106 | return Pattern{}, ErrInvalidPattern |
| 107 | } |
| 108 | stack++ |
| 109 | case utilities.OpCapture: |
| 110 | if op.operand < 0 || len(pool) <= op.operand { |