Class Handler

A handler is a piece of code that can be executed out of sequence, for example when an instruction generates an exception or leaves a finally block.

Each handler has a scope representing the block of instructions guarded by this handler (corresponding to a C# try { ... } block), and a block of instructions to execute when the handler is triggered (corresponding to a catch or finally block).

Handlers are entry points (EntryPoint) so that they can provide values on the stack, for example the value of the current exception. This is why some handlers have a push count of 1.

Either a finally handler (FinallyHandler), filter handler (FilterHandler), catch handler (CatchHandler), or a fault handler (FaultHandler).

Import path

import semmle.code.cil.Handler

Direct supertypes

Indirect supertypes

Known direct subtypes

Predicates

getASuccessorType	Gets a successor to this node, of type `type`, if any.
getCaughtType	Gets the type of the caught exception, if any.
getHandlerStart	Gets the first instruction in the `catch`/`finally` block.
getImplementation	Gets the method containing this control flow node.
getIndex	Gets the 0-based index of this handler. Handlers are evaluated in this sequence.
getLocation
getTryEnd	Gets the last instruction in the `try` block of this handler.
getTryStart	Gets the first instruction in the `try` block of this handler.
isInScope	Holds if the instruction `i` is in the scope of this handler.
toString

Inherited predicates

fromLibrary	Holds if this element is from an assembly.	from Element
fromSource	Holds if this element is from source code.	from Element
getALocation	Gets a location of this element, which can include locations in both DLLs and source files.	from Element
getAPredecessor	Gets a predecessor of this node, if any.	from ControlFlowNode
getAPrimaryQlClass	Gets the name of a primary CodeQL class to which this element belongs.	from Element
getASuccessor	Gets a successor of this node, if any.	from ControlFlowNode
getAnOperand	Gets an operand of this instruction, if any.	from ControlFlowNode
getFalseSuccessor	Gets a false successor of this node, if any.	from ControlFlowNode
getFile	Gets the file containing this element.	from Element
getLanguage	Gets the “language” of this program element, as defined by the extension of the filename. For example, C# has language “cs”, and Visual Basic has language “vb”.	from Element
getOperand	Gets an instruction that supplies the `i`th operand to this instruction. Note that this can be multi-valued.	from ControlFlowNode
getOperandType	Gets the type of the `i`th operand. Unlike `getOperand(i).getType()`, this predicate takes into account when there are multiple possible operands with different types.	from ControlFlowNode
getParentExpr	Gets an expression that consumes the output of this instruction on the stack.	from ControlFlowNode
getPopCount	Gets the number of items this node pops from the stack.	from ControlFlowNode
getPrimaryQlClasses	Gets a comma-separated list of the names of the primary CodeQL classes to which this element belongs.	from Element
getPushCount	Gets the number of items this node pushes onto the stack. This value is either 0 or 1, except for the instruction `dup` which pushes 2 values onto the stack.	from ControlFlowNode
getStackSizeAfter	Gets the stack size after this instruction.	from ControlFlowNode
getStackSizeBefore	Gets the stack size before this instruction.	from EntryPoint
getTrueSuccessor	Gets a true successor of this node, if any.	from ControlFlowNode
getType	Gets the type of the item pushed onto the stack, if any.	from ControlFlowNode
isBranch	Holds if this control flow node has more than one successor.	from ControlFlowNode
isJoin	Holds if this control flow node has more than one predecessor.	from ControlFlowNode
toStringWithTypes	Gets the full textual representation of this element, including type information.	from Element