Support lazy loading object values from toString() (#401)

com.microsoft.java.debug.core/src/main/java/com/microsoft/java/debug/core/adapter/handler/VariablesRequestHandler.java

@@ -47,6 +47,7 @@
 import com.microsoft.java.debug.core.protocol.Requests.Arguments;
 import com.microsoft.java.debug.core.protocol.Requests.Command;
 import com.microsoft.java.debug.core.protocol.Requests.VariablesArguments;
+import com.microsoft.java.debug.core.protocol.Types.VariablePresentationHint;
 import com.microsoft.java.debug.core.protocol.Responses;
 import com.microsoft.java.debug.core.protocol.Types;
 import com.sun.jdi.AbsentInformationException;
@@ -94,6 +95,15 @@ public CompletableFuture<Response> handle(Command command, Arguments arguments,
  }
 
  VariableProxy containerNode = (VariableProxy) container;
+
+ if (containerNode.isLazyVariable() && DebugSettings.getCurrent().showToString) {
+ Types.Variable typedVariable = this.resolveLazyVariable(context, containerNode, variableFormatter, options, evaluationEngine);
+ if (typedVariable != null) {
+ list.add(typedVariable);
+ response.body = new Responses.VariablesResponseBody(list);
+ return CompletableFuture.completedFuture(response);
+ }
+ }
  List<Variable> childrenList = new ArrayList<>();
  IStackFrameManager stackFrameManager = context.getStackFrameManager();
  String containerEvaluateName = containerNode.getEvaluateName();
@@ -266,10 +276,9 @@ public CompletableFuture<Response> handle(Command command, Arguments arguments,
  }
  }
 
- int referenceId = 0;
+ VariableProxy varProxy = null;
  if (indexedVariables > 0 || (indexedVariables < 0 && value instanceof ObjectReference)) {
- VariableProxy varProxy = new VariableProxy(containerNode.getThread(), containerNode.getScope(), value, containerNode, evaluateName);
- referenceId = context.getRecyclableIdPool().addObject(containerNode.getThreadId(), varProxy);
+ varProxy = new VariableProxy(containerNode.getThread(), containerNode.getScope(), value, containerNode, evaluateName);
  varProxy.setIndexedVariable(indexedVariables >= 0);
  varProxy.setUnboundedType(javaVariable.isUnboundedType());
  }
@@ -296,26 +305,38 @@ public CompletableFuture<Response> handle(Command command, Arguments arguments,
  typeString = "";
  }
 
- Types.Variable typedVariables = new Types.Variable(name, valueString, typeString, referenceId, evaluateName);
- typedVariables.indexedVariables = Math.max(indexedVariables, 0);
-
  String detailsValue = null;
  if (hasErrors) {
  // If failed to resolve the variable value, skip the details info as well.
  } else if (sizeValue != null) {
  detailsValue = "size=" + variableFormatter.valueToString(sizeValue, options);
  } else if (DebugSettings.getCurrent().showToString) {
- try {
- detailsValue = VariableDetailUtils.formatDetailsValue(value, containerNode.getThread(), variableFormatter, options, evaluationEngine);
- } catch (OutOfMemoryError e) {
- logger.log(Level.SEVERE, "Failed to compute the toString() value of a large object", e);
- detailsValue = "<Unable to display the details of a large object>";
- } catch (Exception e) {
- logger.log(Level.SEVERE, "Failed to compute the toString() value", e);
- detailsValue = "<Failed to resolve the variable details due to \"" + e.getMessage() + "\">";
+ if (VariableDetailUtils.isLazyLoadingSupported(value) && varProxy != null) {
+ varProxy.setLazyVariable(true);
+ } else {
+ try {
+ detailsValue = VariableDetailUtils.formatDetailsValue(value, containerNode.getThread(), variableFormatter, options, evaluationEngine);
+ } catch (OutOfMemoryError e) {
+ logger.log(Level.SEVERE, "Failed to compute the toString() value of a large object", e);
+ detailsValue = "<Unable to display the details of a large object>";
+ } catch (Exception e) {
+ logger.log(Level.SEVERE, "Failed to compute the toString() value", e);
+ detailsValue = "<Failed to resolve the variable details due to \"" + e.getMessage() + "\">";
+ }
  }
  }
 
+ int referenceId = 0;
+ if (varProxy != null) {
+ referenceId = context.getRecyclableIdPool().addObject(containerNode.getThreadId(), varProxy);
+ }
+
+ Types.Variable typedVariables = new Types.Variable(name, valueString, typeString, referenceId, evaluateName);
+ typedVariables.indexedVariables = Math.max(indexedVariables, 0);
+ if (varProxy != null && varProxy.isLazyVariable()) {
+ typedVariables.presentationHint = new VariablePresentationHint(true);
+ }
+
  if (detailsValue != null) {
  typedVariables.value = typedVariables.value + " " + detailsValue;
  }
@@ -331,6 +352,25 @@ public CompletableFuture<Response> handle(Command command, Arguments arguments,
  return CompletableFuture.completedFuture(response);
  }
 
+ private Types.Variable resolveLazyVariable(IDebugAdapterContext context, VariableProxy containerNode, IVariableFormatter variableFormatter,
+ Map<String, Object> options, IEvaluationProvider evaluationEngine) {
+ VariableProxy valueReferenceProxy = new VariableProxy(containerNode.getThread(), containerNode.getScope(),
+ containerNode.getProxiedVariable(), null /** container */, containerNode.getEvaluateName());
+ valueReferenceProxy.setIndexedVariable(containerNode.isIndexedVariable());
+ valueReferenceProxy.setUnboundedType(containerNode.isUnboundedType());
+ int referenceId = context.getRecyclableIdPool().addObject(containerNode.getThreadId(), valueReferenceProxy);
+ // this proxiedVariable is intermediate object, see https:/microsoft/vscode/issues/135147#issuecomment-1076240074
+ Object proxiedVariable = containerNode.getProxiedVariable();
+ if (proxiedVariable instanceof ObjectReference) {
+ ObjectReference variable = (ObjectReference) proxiedVariable;
+ String valueString = variableFormatter.valueToString(variable, options);
+ String detailString = VariableDetailUtils.formatDetailsValue(variable, containerNode.getThread(), variableFormatter, options,
+ evaluationEngine);
+ return new Types.Variable("", valueString + " " + detailString, "", referenceId, containerNode.getEvaluateName());
+ }
+ return null;
+ }
+
  private Set<String> getDuplicateNames(Collection<String> list) {
  Set<String> result = new HashSet<>();
  Set<String> set = new HashSet<>();

com.microsoft.java.debug.core/src/main/java/com/microsoft/java/debug/core/adapter/variables/VariableDetailUtils.java

@@ -154,4 +154,18 @@ private static boolean isClassType(Value value, String typeName) {
 
  return Objects.equals(((ObjectReference) value).type().name(), typeName);
  }
+
+ public static boolean isLazyLoadingSupported(Value value) {
+ if (isClassType(value, STRING_TYPE)) {
+ return false;
+ }
+ if (!(value instanceof ObjectReference)) {
+ return false;
+ }
+ String inheritedType = findInheritedType(value, COLLECTION_TYPES);
+ if (inheritedType == null && !containsToStringMethod((ObjectReference) value)) {
+ return false;
+ }
+ return true;
+ }
 }

com.microsoft.java.debug.core/src/main/java/com/microsoft/java/debug/core/adapter/variables/VariableProxy.java

@@ -24,6 +24,7 @@ public class VariableProxy {
  private final String evaluateName;
  private boolean isIndexedVariable;
  private boolean isUnboundedType = false;
+ private boolean isLazyVariable = false;
 
  /**
  * Create a variable reference.
@@ -75,7 +76,8 @@ public boolean equals(Object obj) {
  }
  VariableProxy other = (VariableProxy) obj;
  return Objects.equals(scopeName, other.scopeName) && Objects.equals(getThreadId(), other.getThreadId())
- && Objects.equals(variable, other.variable) && Objects.equals(evaluateName, other.evaluateName);
+ && Objects.equals(variable, other.variable) && Objects.equals(evaluateName, other.evaluateName)
+ && Objects.equals(isLazyVariable, other.isLazyVariable);
  }
 
  public long getThreadId() {
@@ -109,4 +111,13 @@ public boolean isUnboundedType() {
  public void setUnboundedType(boolean isUnboundedType) {
  this.isUnboundedType = isUnboundedType;
  }
+
+ public boolean isLazyVariable() {
+ return isLazyVariable;
+ }
+
+ public void setLazyVariable(boolean isLazyVariable) {
+ this.isLazyVariable = isLazyVariable;
+ }
+
 }

com.microsoft.java.debug.core/src/main/java/com/microsoft/java/debug/core/protocol/Types.java

@@ -90,6 +90,7 @@ public static class Variable {
  public int namedVariables;
  public int indexedVariables;
  public String evaluateName;
+ public VariablePresentationHint presentationHint;
 
  /**
  * Constructor.
@@ -343,6 +344,14 @@ public static class ExceptionDetails {
  public ExceptionDetails[] innerException;
  }
 
+ public static class VariablePresentationHint {
+ public boolean lazy;
+
+ public VariablePresentationHint(boolean lazy) {
+ this.lazy = lazy;
+ }
+ }
+
  public static class Capabilities {
  public boolean supportsConfigurationDoneRequest;
  public boolean supportsHitConditionalBreakpoints;