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Closes #9. Using thread local to store method/function argument scrat…
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…ch buffers. Scratch buffers are cleared after method/function call node evaluation to avoid memory leaks.
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@badlogic
badlogic committed Jun 19, 2018
1 parent 831e4b5 commit 20c5012
Showing 1 changed file with 145 additions and 97 deletions.
242 changes: 145 additions & 97 deletions src/main/java/io/marioslab/basis/template/parsing/Ast.java
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Expand Up @@ -796,11 +796,13 @@ public static class FunctionCall extends Expression {
private final Expression function;
private final List<Expression> arguments;
private Object cachedFunction;
private final ThreadLocal<Object[]> cachedArguments;

public FunctionCall (Span span, Expression function, List<Expression> arguments) {
super(span);
this.function = function;
this.arguments = arguments;
this.cachedArguments = new ThreadLocal<Object[]>();
}

/** Return the expression that must evaluate to a {@link FunctionalInterface} or a {@link Macro}. **/
Expand All @@ -826,62 +828,84 @@ public void setCachedFunction (Object cachedFunction) {
this.cachedFunction = cachedFunction;
}

@Override
public Object evaluate (Template template, TemplateContext context, OutputStream out) throws IOException {
Object[] argumentValues = new Object[getArguments().size()];
List<Expression> arguments = getArguments();
for (int i = 0, n = argumentValues.length; i < n; i++) {
Expression expr = arguments.get(i);
argumentValues[i] = expr.evaluate(template, context, out);
/** Returns a scratch buffer to store arguments in when calling the function in {@link AstInterpreter}. Avoids generating
* garbage. **/
public Object[] getCachedArguments () {
Object[] args = cachedArguments.get();
if (args == null) {
args = new Object[arguments.size()];
cachedArguments.set(args);
}
return args;
}

// This is a special case to handle template level macros. If a call to a macro is
// made, evaluating the function expression will result in an exception, as the
// function name can't be found in the context. Instead we need to manually check
// if the function expression is a VariableAccess and if so, if it can be found
// in the context.
Object function = null;
if (getFunction() instanceof VariableAccess) {
VariableAccess varAccess = (VariableAccess)getFunction();
function = context.get(varAccess.getVariableName().getText());
} else {
function = getFunction().evaluate(template, context, out);
}
/** Must be invoked when this node is done evaluating so we don't leak memory **/
public void clearCachedArguments () {
Object[] args = getCachedArguments();
for (int i = 0; i < args.length; i++)
args[i] = null;
}

if (function != null) {
Object method = getCachedFunction();
if (method != null) {
try {
return Reflection.getInstance().callMethod(function, method, argumentValues);
} catch (Throwable t) {
// fall through
}
@Override
public Object evaluate (Template template, TemplateContext context, OutputStream out) throws IOException {
try {
Object[] argumentValues = getCachedArguments();
List<Expression> arguments = getArguments();
for (int i = 0, n = argumentValues.length; i < n; i++) {
Expression expr = arguments.get(i);
argumentValues[i] = expr.evaluate(template, context, out);
}
method = Reflection.getInstance().getMethod(function, null, argumentValues);
if (method == null) Error.error("Couldn't find function.", getSpan());
setCachedFunction(method);
return Reflection.getInstance().callMethod(function, method, argumentValues);
} else {
// Check if this is a call to a macro defined in this template

// This is a special case to handle template level macros. If a call to a macro is
// made, evaluating the function expression will result in an exception, as the
// function name can't be found in the context. Instead we need to manually check
// if the function expression is a VariableAccess and if so, if it can be found
// in the context.
Object function = null;
if (getFunction() instanceof VariableAccess) {
String functionName = ((VariableAccess)getFunction()).getVariableName().getText();
Macros macros = template.getMacros();
Macro macro = macros.get(functionName);
if (macro != null) {
if (macro.getArgumentNames().size() != arguments.size())
Error.error("Expected " + macro.getArgumentNames().size() + " arguments, got " + arguments.size(), getSpan());
TemplateContext macroContext = macro.getMacroContext();
for (int i = 0; i < arguments.size(); i++) {
Object arg = argumentValues[i];
String name = macro.getArgumentNames().get(i).getText();
macroContext.set(name, arg);
VariableAccess varAccess = (VariableAccess)getFunction();
function = context.get(varAccess.getVariableName().getText());
} else {
function = getFunction().evaluate(template, context, out);
}

if (function != null) {
Object method = getCachedFunction();
if (method != null) {
try {
return Reflection.getInstance().callMethod(function, method, argumentValues);
} catch (Throwable t) {
// fall through
}
}
method = Reflection.getInstance().getMethod(function, null, argumentValues);
if (method == null) Error.error("Couldn't find function.", getSpan());
setCachedFunction(method);
return Reflection.getInstance().callMethod(function, method, argumentValues);
} else {
// Check if this is a call to a macro defined in this template
if (getFunction() instanceof VariableAccess) {
String functionName = ((VariableAccess)getFunction()).getVariableName().getText();
Macros macros = template.getMacros();
Macro macro = macros.get(functionName);
if (macro != null) {
if (macro.getArgumentNames().size() != arguments.size())
Error.error("Expected " + macro.getArgumentNames().size() + " arguments, got " + arguments.size(), getSpan());
TemplateContext macroContext = macro.getMacroContext();
for (int i = 0; i < arguments.size(); i++) {
Object arg = argumentValues[i];
String name = macro.getArgumentNames().get(i).getText();
macroContext.set(name, arg);
}
AstInterpreter.interpretNodeList(macro.getBody(), macro.getTemplate(), macroContext, out);
return null;
}
AstInterpreter.interpretNodeList(macro.getBody(), macro.getTemplate(), macroContext, out);
return null;
}
Error.error("Couldn't find function.", getSpan());
return null; // never reached
}
Error.error("Couldn't find function.", getSpan());
return null; // never reached
} finally {
clearCachedArguments();
}
}
}
Expand All @@ -891,11 +915,13 @@ public static class MethodCall extends Expression {
private final MemberAccess method;
private final List<Expression> arguments;
private Object cachedMethod;
private final ThreadLocal<Object[]> cachedArguments;

public MethodCall (Span span, MemberAccess method, List<Expression> arguments) {
super(span);
this.method = method;
this.arguments = arguments;
this.cachedArguments = new ThreadLocal<Object[]>();
}

/** Returns the object on which to call the method. **/
Expand Down Expand Up @@ -926,64 +952,86 @@ public void setCachedMethod (Object cachedMethod) {
this.cachedMethod = cachedMethod;
}

/** Returns a scratch buffer to store arguments in when calling the function in {@link AstInterpreter}. Avoids generating
* garbage. **/
public Object[] getCachedArguments () {
Object[] args = cachedArguments.get();
if (args == null) {
args = new Object[arguments.size()];
cachedArguments.set(args);
}
return args;
}

/** Must be invoked when this node is done evaluating so we don't leak memory **/
public void clearCachedArguments () {
Object[] args = getCachedArguments();
for (int i = 0; i < args.length; i++)
args[i] = null;
}

@Override
public Object evaluate (Template template, TemplateContext context, OutputStream out) throws IOException {
Object object = getObject().evaluate(template, context, out);
if (object == null) Error.error("Couldn't find object in context.", getSpan());

Object[] argumentValues = new Object[getArguments().size()];
List<Expression> arguments = getArguments();
for (int i = 0, n = argumentValues.length; i < n; i++) {
Expression expr = arguments.get(i);
argumentValues[i] = expr.evaluate(template, context, out);
}
try {
Object object = getObject().evaluate(template, context, out);
if (object == null) Error.error("Couldn't find object in context.", getSpan());

Object[] argumentValues = getCachedArguments();
List<Expression> arguments = getArguments();
for (int i = 0, n = argumentValues.length; i < n; i++) {
Expression expr = arguments.get(i);
argumentValues[i] = expr.evaluate(template, context, out);
}

// if the object we call the method on is a Macros instance, lookup the macro by name
// and execute its node list
if (object instanceof Macros) {
Macros macros = (Macros)object;
Macro macro = macros.get(getMethod().getName().getText());
if (macro != null) {
if (macro.getArgumentNames().size() != arguments.size())
Error.error("Expected " + macro.getArgumentNames().size() + " arguments, got " + arguments.size(), getSpan());
TemplateContext macroContext = macro.getMacroContext();
for (int i = 0; i < arguments.size(); i++) {
Object arg = argumentValues[i];
String name = macro.getArgumentNames().get(i).getText();
macroContext.set(name, arg);
// if the object we call the method on is a Macros instance, lookup the macro by name
// and execute its node list
if (object instanceof Macros) {
Macros macros = (Macros)object;
Macro macro = macros.get(getMethod().getName().getText());
if (macro != null) {
if (macro.getArgumentNames().size() != arguments.size())
Error.error("Expected " + macro.getArgumentNames().size() + " arguments, got " + arguments.size(), getSpan());
TemplateContext macroContext = macro.getMacroContext();
for (int i = 0; i < arguments.size(); i++) {
Object arg = argumentValues[i];
String name = macro.getArgumentNames().get(i).getText();
macroContext.set(name, arg);
}
AstInterpreter.interpretNodeList(macro.getBody(), macro.getTemplate(), macroContext, out);
return null;
}
AstInterpreter.interpretNodeList(macro.getBody(), macro.getTemplate(), macroContext, out);
return null;
}
}

// Otherwise try to find a corresponding method or field pointing to a lambda.
Object method = getCachedMethod();
if (method != null) {
try {
return Reflection.getInstance().callMethod(object, method, argumentValues);
} catch (Throwable t) {
// fall through
// Otherwise try to find a corresponding method or field pointing to a lambda.
Object method = getCachedMethod();
if (method != null) {
try {
return Reflection.getInstance().callMethod(object, method, argumentValues);
} catch (Throwable t) {
// fall through
}
}
}

method = Reflection.getInstance().getMethod(object, getMethod().getName().getText(), argumentValues);
if (method != null) {
// found the method on the object, call it
setCachedMethod(method);
return Reflection.getInstance().callMethod(object, method, argumentValues);
} else {
// didn't find the method on the object, try to find a field pointing to a lambda
Object field = Reflection.getInstance().getField(object, getMethod().getName().getText());
if (field == null)
Error.error("Couldn't find method '" + getMethod().getName().getText() + "' for object of type '" + object.getClass().getSimpleName() + "'.",
method = Reflection.getInstance().getMethod(object, getMethod().getName().getText(), argumentValues);
if (method != null) {
// found the method on the object, call it
setCachedMethod(method);
return Reflection.getInstance().callMethod(object, method, argumentValues);
} else {
// didn't find the method on the object, try to find a field pointing to a lambda
Object field = Reflection.getInstance().getField(object, getMethod().getName().getText());
if (field == null)
Error.error("Couldn't find method '" + getMethod().getName().getText() + "' for object of type '" + object.getClass().getSimpleName() + "'.",
getSpan());
Object function = Reflection.getInstance().getFieldValue(object, field);
method = Reflection.getInstance().getMethod(function, null, argumentValues);
if (method == null) Error.error(
"Couldn't find function in field '" + getMethod().getName().getText() + "' for object of type '" + object.getClass().getSimpleName() + "'.",
getSpan());
Object function = Reflection.getInstance().getFieldValue(object, field);
method = Reflection.getInstance().getMethod(function, null, argumentValues);
if (method == null) Error.error(
"Couldn't find function in field '" + getMethod().getName().getText() + "' for object of type '" + object.getClass().getSimpleName() + "'.",
getSpan());
return Reflection.getInstance().callMethod(function, method, argumentValues);
return Reflection.getInstance().callMethod(function, method, argumentValues);
}
} finally {
clearCachedArguments();
}
}
}
Expand Down

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