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PrintAst.qll
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747 lines (655 loc) · 21.8 KB
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/**
* Provides queries to pretty-print a Python AST as a graph.
*
* By default, this will print the AST for all elements in the database. To change this behavior,
* extend `PrintAstConfiguration` and override `shouldPrint` to hold for only the elements
* you wish to view the AST for.
*/
import python
import semmle.python.regexp.RegexTreeView
import semmle.python.Yaml
private newtype TPrintAstConfiguration = MkPrintAstConfiguration()
/**
* The query can extend this class to control which elements are printed.
*/
class PrintAstConfiguration extends TPrintAstConfiguration {
/**
* Gets a textual representation of this `PrintAstConfiguration`.
*/
string toString() { result = "PrintAstConfiguration" }
/**
* Controls whether the `AstNode` should be considered for AST printing.
* By default it checks whether the `AstNode` `e` belongs to `Location` `l`.
*/
predicate shouldPrint(AstNode e, Location l) { l = e.getLocation() }
/**
* Controls whether the `YamlNode` should be considered for AST printing.
* By default it checks whether the `YamlNode` `y` belongs to `Location` `l`.
*/
predicate shouldPrintYaml(YamlNode y, Location l) { l = y.getLocation() }
}
private predicate shouldPrint(AstNode e, Location l) {
exists(PrintAstConfiguration config | config.shouldPrint(e, l))
}
private predicate shouldPrintYaml(YamlNode y, Location l) {
exists(PrintAstConfiguration config | config.shouldPrintYaml(y, l))
}
/** Holds if the given element does not need to be rendered in the AST. */
private predicate isNotNeeded(AstNode el) {
el.isArtificial()
or
el instanceof Module
or
exists(AstNode parent | isNotNeeded(parent) and not parent instanceof Module |
el = parent.getAChildNode()
)
}
/**
* Printed nodes.
*/
private newtype TPrintAstNode =
TElementNode(AstNode el) { shouldPrint(el, _) and not isNotNeeded(el) } or
TFunctionParamsNode(Function f) { shouldPrint(f, _) and not isNotNeeded(f) } or
TCallArgumentsNode(Call c) { shouldPrint(c, _) and not isNotNeeded(c) } or
TStmtListNode(StmtList list) {
shouldPrint(list.getAnItem(), _) and
not list = any(Module mod).getBody() and
not forall(AstNode child | child = list.getAnItem() | isNotNeeded(child))
} or
TYamlNode(YamlNode node) { shouldPrintYaml(node, _) } or
TYamlMappingNode(YamlMapping mapping, int i) {
shouldPrintYaml(mapping, _) and
exists(mapping.getKeyNode(i))
}
/**
* A node in the output tree.
*/
class PrintAstNode extends TPrintAstNode {
/**
* Gets a textual representation of this node in the PrintAst output tree.
*/
string toString() { none() }
/**
* Gets the child node at index `childIndex`. Child indices must be unique,
* but need not be contiguous.
*/
PrintAstNode getChild(int childIndex) { none() }
/**
* Gets a child of this node.
*/
final PrintAstNode getAChild() { result = this.getChild(_) }
/**
* Gets the parent of this node, if any.
*/
final PrintAstNode getParent() { result.getAChild() = this }
/**
* Gets the location of this node in the source code.
*/
Location getLocation() { none() }
/**
* Gets the value of the property of this node, where the name of the property
* is `key`.
*/
string getProperty(string key) {
key = "semmle.label" and
result = this.toString()
}
/**
* Gets the label for the edge from this node to the specified child. By
* default, this is just the index of the child, but subclasses can override
* this.
*/
string getChildEdgeLabel(int childIndex) {
exists(this.getChild(childIndex)) and
result = childIndex.toString()
}
}
/** A top-level AST node. */
class TopLevelPrintAstNode extends PrintAstNode {
TopLevelPrintAstNode() { not exists(this.getParent()) }
private int getOrder() {
this =
rank[result](TopLevelPrintAstNode n, Location l |
l = n.getLocation()
|
n
order by
l.getFile().getRelativePath(), l.getStartLine(), l.getStartColumn(), l.getEndLine(),
l.getEndColumn()
)
}
override string getProperty(string key) {
result = super.getProperty(key)
or
key = "semmle.order" and
result = this.getOrder().toString()
}
}
/**
* An `AstNode` printed in the print-viewer.
*
* This class can be overridden to define more specific behavior for some `AstNode`s.
* The `getChildNode` and `getStmtList` methods can be overridden to easily set up a child-parent relation between different `AstElementNode`s.
* Be very careful about overriding `getChild`, as `getChildNode` and `getStmtList` depend on the default behavior of `getChild`.
*/
class AstElementNode extends PrintAstNode, TElementNode {
AstNode element;
AstElementNode() { this = TElementNode(element) }
override string toString() {
result = "[" + PrettyPrinting::getQlClass(element) + "] " + PrettyPrinting::prettyPrint(element)
}
override Location getLocation() { result = element.getLocation() }
/**
* Gets the `AstNode` that is printed by this print node.
*/
final AstNode getAstNode() { result = element }
override PrintAstNode getChild(int childIndex) {
exists(AstNode el | result.(AstElementNode).getAstNode() = el |
el = this.getChildNode(childIndex) and not el = this.getStmtList(_, _).getAnItem()
)
or
// displaying all `StmtList` after the other children.
exists(int offset | offset = 1 + max([0, any(int index | exists(this.getChildNode(index)))]) |
exists(int index | childIndex = index + offset |
result.(StmtListNode).getList() = this.getStmtList(index, _)
)
)
}
/**
* Gets a child node for the AstNode that this print node represents.
*
* The default behavior in `getChild` uses `getChildNode` to easily define a parent-child relation between different `AstElementNode`s.
*/
AstNode getChildNode(int childIndex) { result = getChild(element, childIndex) }
/**
* Gets the `index`th `StmtList` that is a child of the `AstNode` that this print node represents.
* `label` is used for pretty-printing a label in the parent-child relation in the ast-viewer.
*
* The `StmtListNode` class and the `getChild` predicate uses `getStmtList` to define a parent-child relation with labels.
*
* `index` must be 0 or positive.
*/
StmtList getStmtList(int index, string label) { none() }
}
/**
* A print node for `Try` statements.
*/
class TryNode extends AstElementNode {
override Try element;
override StmtList getStmtList(int index, string label) {
index = 0 and result = element.getBody() and label = "body"
or
index = 1 and result = element.getOrelse() and label = "orelse"
or
index = 2 and result = element.getHandlers() and label = "handlers"
or
index = 3 and result = element.getFinalbody() and label = "final body"
}
}
/**
* A print node for `If` statements.
*/
class IfNode extends AstElementNode {
override If element;
override AstNode getChildNode(int childIndex) { childIndex = 0 and result = element.getTest() }
override StmtList getStmtList(int index, string label) {
index = 1 and result = element.getBody() and label = "body"
or
index = 2 and result = element.getOrelse() and label = "orelse"
}
}
/**
* A print node for classes.
*/
class ClassNode extends AstElementNode {
override Class element;
override StmtList getStmtList(int index, string label) {
index = 1 and result = element.getBody() and label = "body"
}
}
/**
* A print node for `ExceptStmt`.
*/
class ExceptNode extends AstElementNode {
override ExceptStmt element;
override StmtList getStmtList(int index, string label) {
index = 1 and result = element.getBody() and label = "body"
}
}
/**
* A print node for `With` statements.
*/
class WithNode extends AstElementNode {
override With element;
override StmtList getStmtList(int index, string label) {
index = 1 and result = element.getBody() and label = "body"
}
}
/**
* A print node for `For` statements.
*/
class ForPrintNode extends AstElementNode {
override For element;
override StmtList getStmtList(int index, string label) {
index = 1 and result = element.getBody() and label = "body"
or
index = 2 and result = element.getOrelse() and label = "orelse"
}
}
/**
* A print node for `While` statements.
*/
class WhilePrintNode extends AstElementNode {
override While element;
override StmtList getStmtList(int index, string label) {
index = 1 and result = element.getBody() and label = "body"
or
index = 2 and result = element.getOrelse() and label = "orelse"
}
}
/**
* A print node for `StmtList`.
* A `StmtListNode` is always a child of an `AstElementNode`,
* and the child-parent relation is defined by the `getStmtList` predicate in `AstElementNode`.
*
* The label for a `StmtList` is decided based on the result from the `getStmtList` predicate in `AstElementNode`.
*/
class StmtListNode extends PrintAstNode, TStmtListNode {
StmtList list;
StmtListNode() {
this = TStmtListNode(list) and
list = any(AstElementNode node).getStmtList(_, _)
}
/**
* Gets the `StmtList` that this print node represents.
*/
StmtList getList() { result = list }
private string getLabel() { this.getList() = any(AstElementNode node).getStmtList(_, result) }
override string toString() { result = "(StmtList) " + this.getLabel() }
override PrintAstNode getChild(int childIndex) {
exists(AstNode el | result.(AstElementNode).getAstNode() = el | el = list.getItem(childIndex))
}
}
/**
* A print node for a `Call`.
*
* The arguments to this call are aggregated into a `CallArgumentsNode`.
*/
class CallPrintNode extends AstElementNode {
override Call element;
override PrintAstNode getChild(int childIndex) {
childIndex = 0 and result.(AstElementNode).getAstNode() = element.getFunc()
or
childIndex = 1 and result.(CallArgumentsNode).getCall() = element
}
}
/**
* A synthetic print node for the arguments to `call`.
*/
class CallArgumentsNode extends PrintAstNode, TCallArgumentsNode {
Call call;
CallArgumentsNode() { this = TCallArgumentsNode(call) }
/**
* Gets the call for which this print node represents the arguments.
*/
Call getCall() { result = call }
override string toString() { result = "(arguments)" }
override PrintAstNode getChild(int childIndex) {
result.(AstElementNode).getAstNode() = getChild(call, childIndex) and
not result.(AstElementNode).getAstNode() = call.getFunc()
}
}
/**
* A print node for a `Function`.
*/
class FunctionNode extends AstElementNode {
override Function element;
override PrintAstNode getChild(int childIndex) {
exists(FunctionParamsNode paramsNode | paramsNode.getFunction() = element |
childIndex = 0 and result = paramsNode
or
result = AstElementNode.super.getChild(childIndex) and
// parameters is handled above
not result.(AstElementNode).getAstNode() =
paramsNode.getChild(_).(AstElementNode).getAstNode() and
// The default of a Parameter is handled by `ParameterNode`
not result.(AstElementNode).getAstNode() = any(Parameter param).getDefault() and
// The annotation is a parameter is handled by `ParameterNode`.
not result.(AstElementNode).getAstNode() = any(Parameter param).getAnnotation()
)
}
override StmtList getStmtList(int index, string label) {
index = 1 and result = element.getBody() and label = "body"
}
}
/**
* A print node for a `FunctionDef`.
*/
class FunctionDefNode extends AstElementNode {
override FunctionDef element;
override AstNode getChildNode(int childIndex) {
childIndex = 0 and result = element.getTarget(0)
or
childIndex = 1 and result = element.getValue()
}
}
/**
* A print node for the parameters in `func`.
*/
class FunctionParamsNode extends PrintAstNode, TFunctionParamsNode {
Function func;
FunctionParamsNode() { this = TFunctionParamsNode(func) }
/**
* Gets the `Function` that this print node represents.
*/
Function getFunction() { result = func }
override string toString() { result = "(parameters)" }
override PrintAstNode getChild(int childIndex) {
// everything that is not a stmt is a parameter.
exists(AstNode el | result.(AstElementNode).getAstNode() = el |
el = getChild(func, childIndex) and not el = func.getAStmt()
)
}
}
/**
* A print node for a `Parameter`.
*
* This print node has the annotation and default value of the `Parameter` as children.
* The type annotation and default value would by default exist as children of the parent `Function`.
*/
class ParameterNode extends AstElementNode {
Parameter param;
ParameterNode() { this.getAstNode() = param.asName() or this.getAstNode() = param.asTuple() }
override AstNode getChildNode(int childIndex) {
childIndex = 0 and result = param.getAnnotation()
or
childIndex = 1 and result = param.getDefault()
}
}
/**
* A print node for a `StringLiteral`.
*
* The string has a child, if the child is used as a regular expression,
* which is the root of the regular expression.
*/
class StringLiteralNode extends AstElementNode {
override StringLiteral element;
}
/**
* Gets the `i`th child from `node` ordered by location.
*/
private AstNode getChild(AstNode node, int i) {
shouldPrint(node, _) and
result =
rank[i](AstNode child |
child = node.getAChildNode()
|
child
order by
child.getLocation().getStartLine(), child.getLocation().getStartColumn(),
child.getLocation().getEndLine(), child.getLocation().getEndColumn()
)
}
/**
* A module for pretty-printing some `AstNode`s.
*/
private module PrettyPrinting {
/**
* Gets the QL class for the `AstNode` `a`.
* Most `AstNode`s print their QL class in the `toString()` method, however there are exceptions.
* These exceptions are handled in the `getQlCustomClass` predicate.
*/
string getQlClass(AstNode a) {
shouldPrint(a, _) and
(
not exists(getQlCustomClass(a)) and result = strictconcat(a.toString(), " | ")
or
result = strictconcat(getQlCustomClass(a), " | ")
)
}
/**
* Gets the QL class for `AstNode`s where the `toString` method does not print the QL class.
*/
string getQlCustomClass(AstNode a) {
shouldPrint(a, _) and
(
a instanceof Name and
result = "Name" and
not a instanceof Parameter and
not a instanceof NameConstant
or
a instanceof Parameter and result = "Parameter"
or
a instanceof PlaceHolder and result = "PlaceHolder"
or
a instanceof Function and result = "Function"
or
a instanceof Class and result = "Class"
or
a instanceof Call and result = "Call"
or
a instanceof NameConstant and result = "NameConstant"
)
}
/**
* Gets a human-readable representation of the `AstNode` `a`, or the empty string.
*
* Has exactly one result for every `AstNode`.
*/
string prettyPrint(AstNode a) {
shouldPrint(a, _) and
(
// this strictconcat should not be needed.
// However, the printAst feature breaks if this predicate has more than one result for an `AstNode`, so the strictconcat stays.
result = strictconcat(reprRec(a), " | ")
or
not exists(reprRec(a)) and
result = ""
)
}
/**
* Gets a human-readable representation of the given `AstNode`.
*
* Only has a result for some `AstNode`s.
*
* The monotonicity of this recursive predicate is kept by defining the non-recursive cases inside the `reprBase` predicate,
* and then using `reprBase` when there is a negative edge.
*/
private string reprRec(AstNode a) {
shouldPrint(a, _) and
not isNotNeeded(a) and
(
// For NameNodes, we just use the underlying variable name
result = reprBase(a)
or
exists(Expr obj |
obj = a.(Attribute).getObject() // Attribute .getname .getObject
|
// Attributes of the form `name.name2`
result = reprBase(obj) + "." + a.(Attribute).getName()
or
// Attributes where the object is a more complicated expression
not exists(reprBase(obj)) and
result = "(...)." + a.(Attribute).getName()
)
or
result = "import " + reprRec(a.(Import).getName(_).getAsname())
or
exists(Keyword keyword | keyword = a |
result = keyword.getArg() + "=" + reprRec(keyword.getValue())
)
or
result = reprRec(a.(Call).getFunc()) + "(" + printArgs(a) + ")"
or
not exists(printArgs(a)) and result = reprRec(a.(Call).getFunc()) + "(...)"
or
result = "try " + reprRec(a.(Try).getBody().getItem(0))
or
result = "if " + reprRec(a.(If).getTest()) + ":"
or
result = reprRec(a.(Compare).getLeft()) + " " + a.(Compare).getOp(0).getSymbol() + " ..."
or
result = a.(Subscript).getObject() + "[" + reprRec(a.(Subscript).getIndex()) + "]"
or
exists(Assign asn | asn = a |
strictcount(asn.getTargets()) = 1 and
result = reprRec(a.(Assign).getTarget(0)) + " = " + reprRec(asn.getValue())
)
or
result = "return " + reprRec(a.(Return).getValue())
or
result = reprRec(a.(ExprStmt).getValue())
or
exists(BoolExpr b, string op |
a = b and
(
b.getOp() instanceof And and op = "and"
or
b.getOp() instanceof Or and op = "or"
)
|
result = reprRec(b.getValue(0)) + " " + op + " " + reprRec(b.getValue(1))
)
)
}
/**
* Gets a comma separated pretty printed list of the arguments in `call`.
*/
string printArgs(Call call) {
not exists(call.getAnArg()) and result = ""
or
result = strictconcat(int i | | reprBase(call.getArg(i)), ", ")
}
/**
* Gets a human-readable representation of the given `AstNode`.
* Is only defined for `AstNode`s for which a human-readable representation can be created without using recursion.
*/
private string reprBase(AstNode a) {
shouldPrint(a, _) and
not isNotNeeded(a) and
(
result = a.(Name).getId()
or
result = a.(PlaceHolder).toString()
or
result = "class " + a.(ClassExpr).getName()
or
result = "class " + a.(Class).getName()
or
result = a.(StringLiteral).getText()
or
result = "yield " + a.(Yield).getValue()
or
result = "yield from " + a.(YieldFrom).getValue()
or
result = "*" + a.(Starred).getValue()
or
result = "`" + a.(Repr).getValue() + "`"
or
a instanceof Ellipsis and result = "..."
or
result = a.(Num).getText()
or
result = a.(NegativeIntegerLiteral).getValue().toString()
or
result = a.(NameConstant).toString()
or
result = "await " + a.(Await).getValue()
or
result = "function " + a.(FunctionExpr).getName() + "(...)"
or
result = "function " + a.(Function).getName() + "(...)"
or
a instanceof List and result = "[...]"
or
a instanceof Set and result = "{...}"
or
a instanceof Continue and result = "continue"
or
a instanceof Break and result = "break"
or
a instanceof Pass and result = "pass"
)
}
}
/**
* Classes for printing YAML AST.
*/
module PrintYaml {
/**
* A print node representing a YAML value in a .yml file.
*/
class YamlNodeNode extends PrintAstNode, TYamlNode {
YamlNode node;
YamlNodeNode() { this = TYamlNode(node) }
override string toString() {
result = "[" + concat(node.getAPrimaryQlClass(), ",") + "] " + node.toString()
}
override Location getLocation() { result = node.getLocation() }
/**
* Gets the `YAMLNode` represented by this node.
*/
final YamlNode getValue() { result = node }
override PrintAstNode getChild(int childIndex) {
exists(YamlNode child | result.(YamlNodeNode).getValue() = child |
child = node.getChildNode(childIndex)
)
}
}
/**
* A print node representing a `YAMLMapping`.
*
* Each child of this node aggregates the key and value of a mapping.
*/
class YamlMappingNode extends YamlNodeNode {
override YamlMapping node;
override PrintAstNode getChild(int childIndex) {
exists(YamlMappingMapNode map | map = result | map.maps(node, childIndex))
}
}
/**
* A print node representing the `i`th mapping in `mapping`.
*/
class YamlMappingMapNode extends PrintAstNode, TYamlMappingNode {
YamlMapping mapping;
int i;
YamlMappingMapNode() { this = TYamlMappingNode(mapping, i) }
override string toString() {
result = "(Mapping " + i + ")" and not exists(mapping.getKeyNode(i).(YamlScalar).getValue())
or
result = "(Mapping " + i + ") " + mapping.getKeyNode(i).(YamlScalar).getValue() + ":"
}
/**
* Holds if this print node represents the `index`th mapping of `m`.
*/
predicate maps(YamlMapping m, int index) {
m = mapping and
index = i
}
override PrintAstNode getChild(int childIndex) {
childIndex = 0 and result.(YamlNodeNode).getValue() = mapping.getKeyNode(i)
or
childIndex = 1 and result.(YamlNodeNode).getValue() = mapping.getValueNode(i)
}
}
}
/** Holds if `node` belongs to the output tree, and its property `key` has the given `value`. */
query predicate nodes(PrintAstNode node, string key, string value) { value = node.getProperty(key) }
/**
* Holds if `target` is a child of `source` in the AST, and property `key` of the edge has the
* given `value`.
*/
query predicate edges(PrintAstNode source, PrintAstNode target, string key, string value) {
exists(int childIndex |
target = source.getChild(childIndex) and
(
key = "semmle.label" and value = source.getChildEdgeLabel(childIndex)
or
key = "semmle.order" and value = childIndex.toString()
)
)
}
/** Holds if property `key` of the graph has the given `value`. */
query predicate graphProperties(string key, string value) {
key = "semmle.graphKind" and value = "tree"
}