/*
* Copyright 2014 Attila Szegedi, Daniel Dekany, Jonathan Revusky
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package freemarker.core;
import java.util.Date;
import freemarker.ext.beans.BeanModel;
import freemarker.ext.beans._BeansAPI;
import freemarker.template.TemplateBooleanModel;
import freemarker.template.TemplateCollectionModel;
import freemarker.template.TemplateDateModel;
import freemarker.template.TemplateException;
import freemarker.template.TemplateModel;
import freemarker.template.TemplateModelException;
import freemarker.template.TemplateNumberModel;
import freemarker.template.TemplateScalarModel;
import freemarker.template.TemplateSequenceModel;
/**
* Internally used static utilities for evaluation expressions.
*/
class EvalUtil
{
static final int CMP_OP_EQUALS = 1;
static final int CMP_OP_NOT_EQUALS = 2;
static final int CMP_OP_LESS_THAN = 3;
static final int CMP_OP_GREATER_THAN = 4;
static final int CMP_OP_LESS_THAN_EQUALS = 5;
static final int CMP_OP_GREATER_THAN_EQUALS = 6;
// If you add a new operator here, update the "compare" and "cmpOpToString" methods!
// Prevents instantination.
private EvalUtil() { }
/**
* @param expr {@code null} is allowed, but may results in less helpful error messages
* @param env {@code null} is allowed, but may results in lower performance in classic-compatible mode
*/
static String modelToString(TemplateScalarModel model, Expression expr, Environment env)
throws TemplateModelException {
String value = model.getAsString();
if(value == null) {
if (env == null) env = Environment.getCurrentEnvironment();
if (env != null && env.isClassicCompatible()) {
return "";
} else {
throw newModelHasStoredNullException(String.class, model, expr);
}
}
return value;
}
/**
* @param expr {@code null} is allowed, but may results in less helpful error messages
*/
static Number modelToNumber(TemplateNumberModel model, Expression expr)
throws TemplateModelException
{
Number value = model.getAsNumber();
if(value == null) throw newModelHasStoredNullException(Number.class, model, expr);
return value;
}
/**
* @param expr {@code null} is allowed, but may results in less helpful error messages
*/
static Date modelToDate(TemplateDateModel model, Expression expr)
throws TemplateModelException
{
Date value = model.getAsDate();
if(value == null) throw newModelHasStoredNullException(Date.class, model, expr);
return value;
}
/** Signals the buggy case where we have a non-null model, but its wraps a null. */
private static TemplateModelException newModelHasStoredNullException(
Class expected, TemplateModel model, Expression expr) {
return new _TemplateModelException(expr, _TemplateModelException.modelHasStoredNullDescription(expected, model));
}
/**
* Compares two expressions according the rules of the FTL comparator operators.
*
* @param leftExp not {@code null}
* @param operator one of the {@code COMP_OP_...} constants, like {@link #CMP_OP_EQUALS}.
* @param operatorString can be null {@code null}; the actual operator used, used for more accurate error message.
* @param rightExp not {@code null}
* @param env {@code null} is tolerated, but should be avoided
*/
static boolean compare(
Expression leftExp,
int operator, String operatorString,
Expression rightExp,
Expression defaultBlamed,
Environment env) throws TemplateException {
TemplateModel ltm = leftExp.eval(env);
TemplateModel rtm = rightExp.eval(env);
return compare(
ltm, leftExp,
operator, operatorString,
rtm, rightExp,
defaultBlamed,
false, false, false,
env);
}
/**
* Compares values according the rules of the FTL comparator operators; if the {@link Expression}-s are
* accessible, use {@link #compare(Expression, int, String, Expression, Expression, Environment)} instead, as
* that gives better error messages.
*
* @param leftValue maybe {@code null}, which will usually cause the appropriate {@link TemplateException}.
* @param operator one of the {@code COMP_OP_...} constants, like {@link #CMP_OP_EQUALS}.
* @param rightValue maybe {@code null}, which will usually cause the appropriate {@link TemplateException}.
* @param env {@code null} is tolerated, but should be avoided
*/
static boolean compare(
TemplateModel leftValue, int operator, TemplateModel rightValue,
Environment env) throws TemplateException {
return compare(
leftValue, null,
operator, null,
rightValue, null,
null,
false, false, false,
env);
}
/**
* Same as {@link #compare(TemplateModel, int, TemplateModel, Environment)}, but if the two types are incompatible,
* they are treated as non-equal instead of throwing an exception. Comparing dates of different types will
* still throw an exception, however.
*/
static boolean compareLenient(
TemplateModel leftValue, int operator, TemplateModel rightValue,
Environment env) throws TemplateException {
return compare(
leftValue, null,
operator, null,
rightValue, null,
null,
true, false, false,
env);
}
private static final String VALUE_OF_THE_COMPARISON_IS_UNKNOWN_DATE_LIKE
= "value of the comparison is a date-like value where "
+ "it's not known if it's a date (no time part), time, or date-time, "
+ "and thus can't be used in a comparison.";
/**
* @param leftExp {@code null} is allowed, but may results in less helpful error messages
* @param operator one of the {@code COMP_OP_...} constants, like {@link #CMP_OP_EQUALS}.
* @param operatorString can be null {@code null}; the actual operator used, used for more accurate error message.
* @param rightExp {@code null} is allowed, but may results in less helpful error messages
* @param defaultBlamed {@code null} allowed; the expression who to which error will point to if something goes
* wrong that is not specific to the left or right side expression, or if that expression is {@code null}.
* @param typeMismatchMeansNotEqual If the two types are incompatible, they are treated as non-equal instead
* of throwing an exception. Comparing dates of different types will still throw an exception, however.
* @param leftNullReturnsFalse if {@code true}, a {@code null} left value will not cause exception, but make the
* expression {@code false}.
* @param rightNullReturnsFalse if {@code true}, a {@code null} right value will not cause exception, but make the
* expression {@code false}.
*/
static boolean compare(
TemplateModel leftValue, Expression leftExp,
int operator, String operatorString,
TemplateModel rightValue, Expression rightExp,
Expression defaultBlamed,
boolean typeMismatchMeansNotEqual,
boolean leftNullReturnsFalse, boolean rightNullReturnsFalse,
Environment env) throws TemplateException {
if (leftValue == null) {
if (env != null && env.isClassicCompatible()) {
leftValue = TemplateScalarModel.EMPTY_STRING;
} else {
if (leftNullReturnsFalse) {
return false;
} else {
if (leftExp != null) {
throw InvalidReferenceException.getInstance(leftExp, env);
} else {
throw new _MiscTemplateException(defaultBlamed, env,
"The left operand of the comparison was undefined or null.");
}
}
}
}
if (rightValue == null) {
if (env != null && env.isClassicCompatible()) {
rightValue = TemplateScalarModel.EMPTY_STRING;
} else {
if (rightNullReturnsFalse) {
return false;
} else {
if (rightExp != null) {
throw InvalidReferenceException.getInstance(rightExp, env);
} else {
throw new _MiscTemplateException(defaultBlamed, env,
"The right operand of the comparison was undefined or null.");
}
}
}
}
final int cmpResult;
if (leftValue instanceof TemplateNumberModel && rightValue instanceof TemplateNumberModel) {
Number leftNum = EvalUtil.modelToNumber((TemplateNumberModel) leftValue, leftExp);
Number rightNum = EvalUtil.modelToNumber((TemplateNumberModel) rightValue, rightExp);
ArithmeticEngine ae =
env != null
? env.getArithmeticEngine()
: (leftExp != null
? leftExp.getTemplate().getArithmeticEngine()
: ArithmeticEngine.BIGDECIMAL_ENGINE);
try {
cmpResult = ae.compareNumbers(leftNum, rightNum);
} catch (RuntimeException e) {
throw new _MiscTemplateException(defaultBlamed, e, env, new Object[]
{ "Unexpected error while comparing two numbers: ", e });
}
} else if (leftValue instanceof TemplateDateModel && rightValue instanceof TemplateDateModel) {
TemplateDateModel leftDateModel = (TemplateDateModel) leftValue;
TemplateDateModel rightDateModel = (TemplateDateModel) rightValue;
int leftDateType = leftDateModel.getDateType();
int rightDateType = rightDateModel.getDateType();
if (leftDateType == TemplateDateModel.UNKNOWN || rightDateType == TemplateDateModel.UNKNOWN) {
String sideName;
Expression sideExp;
if (leftDateType == TemplateDateModel.UNKNOWN) {
sideName = "left";
sideExp = leftExp;
} else {
sideName = "right";
sideExp = rightExp;
}
throw new _MiscTemplateException(sideExp != null ? sideExp : defaultBlamed, env, new Object[] {
"The ", sideName, " ", VALUE_OF_THE_COMPARISON_IS_UNKNOWN_DATE_LIKE });
}
if (leftDateType != rightDateType) {
;
throw new _MiscTemplateException(defaultBlamed, env, new Object[] {
"Can't compare dates of different types. Left date type is ",
TemplateDateModel.TYPE_NAMES.get(leftDateType), ", right date type is ",
TemplateDateModel.TYPE_NAMES.get(rightDateType), "." });
}
Date leftDate = EvalUtil.modelToDate(leftDateModel, leftExp);
Date rightDate = EvalUtil.modelToDate(rightDateModel, rightExp);
cmpResult = leftDate.compareTo(rightDate);
} else if (leftValue instanceof TemplateScalarModel && rightValue instanceof TemplateScalarModel) {
if (operator != CMP_OP_EQUALS && operator != CMP_OP_NOT_EQUALS) {
throw new _MiscTemplateException(defaultBlamed, env, new Object[] {
"Can't use operator \"", cmpOpToString(operator, operatorString), "\" on string values." });
}
String leftString = EvalUtil.modelToString((TemplateScalarModel) leftValue, leftExp, env);
String rightString = EvalUtil.modelToString((TemplateScalarModel) rightValue, rightExp, env);
// FIXME NBC: Don't use the Collator here. That's locale-specific, but ==/!= should not be.
cmpResult = env.getCollator().compare(leftString, rightString);
} else if (leftValue instanceof TemplateBooleanModel && rightValue instanceof TemplateBooleanModel) {
if (operator != CMP_OP_EQUALS && operator != CMP_OP_NOT_EQUALS) {
throw new _MiscTemplateException(defaultBlamed, env, new Object[] {
"Can't use operator \"", cmpOpToString(operator, operatorString), "\" on boolean values." });
}
boolean leftBool = ((TemplateBooleanModel) leftValue).getAsBoolean();
boolean rightBool = ((TemplateBooleanModel) rightValue).getAsBoolean();
cmpResult = (leftBool ? 1 : 0) - (rightBool ? 1 : 0);
} else if (env.isClassicCompatible()) {
String leftSting = leftExp.evalAndCoerceToString(env);
String rightString = rightExp.evalAndCoerceToString(env);
cmpResult = env.getCollator().compare(leftSting, rightString);
} else {
if (typeMismatchMeansNotEqual) {
if (operator == CMP_OP_EQUALS) {
return false;
} else if (operator == CMP_OP_NOT_EQUALS) {
return true;
}
// Falls through
}
throw new _MiscTemplateException(defaultBlamed, env, new Object[] {
"Can't compare values of these types. ",
"Allowed comparisons are between two numbers, two strings, two dates, or two booleans.\n",
"Left hand operand is ", new _DelayedAOrAn(new _DelayedFTLTypeDescription(leftValue)), ".\n",
"Right hand operand is ", new _DelayedAOrAn(new _DelayedFTLTypeDescription(rightValue)), "." });
}
switch (operator) {
case CMP_OP_EQUALS: return cmpResult == 0;
case CMP_OP_NOT_EQUALS: return cmpResult != 0;
case CMP_OP_LESS_THAN: return cmpResult < 0;
case CMP_OP_GREATER_THAN: return cmpResult > 0;
case CMP_OP_LESS_THAN_EQUALS: return cmpResult <= 0;
case CMP_OP_GREATER_THAN_EQUALS: return cmpResult >= 0;
default: throw new BugException("Unsupported comparator operator code: " + operator);
}
}
private static String cmpOpToString(int operator, String operatorString) {
if (operatorString != null) {
return operatorString;
} else {
switch (operator) {
case CMP_OP_EQUALS: return "equals";
case CMP_OP_NOT_EQUALS: return "not-equals";
case CMP_OP_LESS_THAN: return "less-than";
case CMP_OP_GREATER_THAN: return "greater-than";
case CMP_OP_LESS_THAN_EQUALS: return "less-than-equals";
case CMP_OP_GREATER_THAN_EQUALS: return "greater-than-equals";
default: return "???";
}
}
}
static String coerceModelToString(TemplateModel tm, Expression exp, String seqHint, Environment env) throws TemplateException {
if (tm instanceof TemplateNumberModel) {
return env.formatNumber(modelToNumber((TemplateNumberModel) tm, exp));
} else if (tm instanceof TemplateDateModel) {
return env.formatDate((TemplateDateModel) tm, exp);
} else if (tm instanceof TemplateScalarModel) {
return modelToString((TemplateScalarModel) tm, exp, env);
} else if(tm == null) {
if (env.isClassicCompatible()) {
return "";
} else {
if (exp != null) {
throw InvalidReferenceException.getInstance(exp, env);
} else {
throw new InvalidReferenceException(
"Null/missing value (no more informatoin avilable)",
env);
}
}
} else if (tm instanceof TemplateBooleanModel) {
// This should be before TemplateScalarModel, but automatic boolean-to-string is only non-error since 2.3.20
// (and before that when classic_compatible was true), so to keep backward compatibility we couldn't insert
// this before TemplateScalarModel.
boolean booleanValue = ((TemplateBooleanModel) tm).getAsBoolean();
int compatMode = env.getClassicCompatibleAsInt();
if (compatMode == 0) {
return env.formatBoolean(booleanValue, false);
} else {
if (compatMode == 1) {
return booleanValue ? MiscUtil.C_TRUE : "";
} else if (compatMode == 2) {
if (tm instanceof BeanModel) {
// In 2.1, bean-wrapped booleans where strings, so that has overridden the boolean behavior:
return _BeansAPI.getAsClassicCompatibleString((BeanModel) tm);
} else {
return booleanValue ? MiscUtil.C_TRUE : "";
}
} else {
throw new BugException("Unsupported classic_compatible variation: " + compatMode);
}
}
} else {
if (env.isClassicCompatible() && tm instanceof BeanModel) {
return _BeansAPI.getAsClassicCompatibleString((BeanModel) tm);
} if (seqHint != null && (tm instanceof TemplateSequenceModel || tm instanceof TemplateCollectionModel)) {
throw new NonStringException(exp, tm, seqHint, env);
} else {
throw new NonStringException(exp, tm, env);
}
}
}
}