github.com/nspcc-dev/neo-go@v0.105.2-0.20240517133400-6be757af3eba/pkg/vm/exception.go (about)

     1  package vm
     2  
     3  import (
     4  	"errors"
     5  	"math/big"
     6  
     7  	"github.com/nspcc-dev/neo-go/pkg/vm/stackitem"
     8  )
     9  
    10  // exceptionHandlingState represents state of the exception handling process.
    11  type exceptionHandlingState byte
    12  
    13  const (
    14  	eTry exceptionHandlingState = iota
    15  	eCatch
    16  	eFinally
    17  )
    18  
    19  // exceptionHandlingContext represents context of the exception handling process.
    20  type exceptionHandlingContext struct {
    21  	CatchOffset   int
    22  	FinallyOffset int
    23  	EndOffset     int
    24  	State         exceptionHandlingState
    25  }
    26  
    27  func newExceptionHandlingContext(cOffset, fOffset int) *exceptionHandlingContext {
    28  	return &exceptionHandlingContext{
    29  		CatchOffset:   cOffset,
    30  		FinallyOffset: fOffset,
    31  		EndOffset:     -1,
    32  		State:         eTry,
    33  	}
    34  }
    35  
    36  // HasCatch returns true iff the context has a `catch` block.
    37  func (c *exceptionHandlingContext) HasCatch() bool { return c.CatchOffset >= 0 }
    38  
    39  // HasFinally returns true iff the context has a `finally` block.
    40  func (c *exceptionHandlingContext) HasFinally() bool { return c.FinallyOffset >= 0 }
    41  
    42  // String implements the stackitem.Item interface.
    43  func (c *exceptionHandlingContext) String() string {
    44  	return "exception handling context"
    45  }
    46  
    47  // Value implements the stackitem.Item interface.
    48  func (c *exceptionHandlingContext) Value() any {
    49  	return c
    50  }
    51  
    52  // Dup implements the stackitem.Item interface.
    53  func (c *exceptionHandlingContext) Dup() stackitem.Item {
    54  	return c
    55  }
    56  
    57  // TryBool implements the stackitem.Item interface.
    58  func (c *exceptionHandlingContext) TryBool() (bool, error) {
    59  	panic("can't convert exceptionHandlingContext to Bool")
    60  }
    61  
    62  // TryBytes implements the stackitem.Item interface.
    63  func (c *exceptionHandlingContext) TryBytes() ([]byte, error) {
    64  	return nil, errors.New("can't convert exceptionHandlingContext to ByteArray")
    65  }
    66  
    67  // TryInteger implements the stackitem.Item interface.
    68  func (c *exceptionHandlingContext) TryInteger() (*big.Int, error) {
    69  	return nil, errors.New("can't convert exceptionHandlingContext to Integer")
    70  }
    71  
    72  // Type implements the stackitem.Item interface.
    73  func (c *exceptionHandlingContext) Type() stackitem.Type {
    74  	panic("exceptionHandlingContext cannot appear on evaluation stack")
    75  }
    76  
    77  // Convert implements the stackitem.Item interface.
    78  func (c *exceptionHandlingContext) Convert(_ stackitem.Type) (stackitem.Item, error) {
    79  	panic("exceptionHandlingContext cannot be converted to anything")
    80  }
    81  
    82  // Equals implements the stackitem.Item interface.
    83  func (c *exceptionHandlingContext) Equals(s stackitem.Item) bool {
    84  	return c == s
    85  }