dev.cel.common.ast.CelExprFormatter Maven / Gradle / Ivy
Go to download
Show more of this group Show more artifacts with this name
Show all versions of runtime Show documentation
Show all versions of runtime Show documentation
Common Expression Language Runtime for Java
// Copyright 2023 Google LLC
//
// 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
//
// https://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 dev.cel.common.ast;
import com.google.common.collect.ImmutableSet;
/** Provides string formatting support for {@link CelExpr}. */
final class CelExprFormatter {
private final StringBuilder indent = new StringBuilder();
private final StringBuilder exprBuilder = new StringBuilder();
/** Denotes a set of expression kinds that will not have a new line inserted. */
private static final ImmutableSet EXCLUDED_NEWLINE_KINDS =
ImmutableSet.of(CelExpr.ExprKind.Kind.CONSTANT, CelExpr.ExprKind.Kind.NOT_SET);
static String format(CelExpr celExpr) {
CelExprFormatter formatter = new CelExprFormatter();
formatter.formatExpr(celExpr);
return formatter.exprBuilder.toString();
}
private void formatExpr(CelExpr celExpr) {
CelExpr.ExprKind.Kind exprKind = celExpr.exprKind().getKind();
append(String.format("%s [%d] {", exprKind, celExpr.id()));
if (!EXCLUDED_NEWLINE_KINDS.contains(exprKind)) {
appendNewline();
}
switch (exprKind) {
case CONSTANT:
appendConst(celExpr.constant());
break;
case IDENT:
appendIdent(celExpr.ident());
break;
case SELECT:
appendSelect(celExpr.select());
break;
case CALL:
appendCall(celExpr.call());
break;
case LIST:
appendList(celExpr.list());
break;
case STRUCT:
appendStruct(celExpr.struct());
break;
case MAP:
appendMap(celExpr.map());
break;
case COMPREHENSION:
appendComprehension(celExpr.comprehension());
break;
case NOT_SET:
break;
default:
// This should be unreachable unless if we've added any other kinds.
indent();
append("Unknown kind: " + exprKind);
outdent();
break;
}
if (!EXCLUDED_NEWLINE_KINDS.contains(exprKind)) {
appendNewline();
append("}");
} else {
appendWithoutIndent("}");
}
}
private void appendConst(CelConstant celConstant) {
appendWithoutIndent(" value: ");
switch (celConstant.getKind()) {
case NULL_VALUE:
appendWithoutIndent("null");
break;
case BOOLEAN_VALUE:
appendWithoutIndent(Boolean.toString(celConstant.booleanValue()));
break;
case INT64_VALUE:
appendWithoutIndent(Long.toString(celConstant.int64Value()));
break;
case UINT64_VALUE:
appendWithoutIndent(celConstant.uint64Value() + "u");
break;
case DOUBLE_VALUE:
appendWithoutIndent(Double.toString(celConstant.doubleValue()));
break;
case STRING_VALUE:
appendWithoutIndent("\"" + celConstant.stringValue() + "\"");
break;
case BYTES_VALUE:
appendWithoutIndent(String.format("b\"%s\"", celConstant.bytesValue().toStringUtf8()));
break;
default:
append("Unknown kind: " + celConstant.getKind());
break;
}
appendWithoutIndent(" ");
}
private void appendIdent(CelExpr.CelIdent celIdent) {
indent();
append("name: " + celIdent.name());
outdent();
}
private void appendSelect(CelExpr.CelSelect celSelect) {
indent();
formatExpr(celSelect.operand());
outdent();
appendWithoutIndent(".");
appendWithoutIndent(celSelect.field());
if (celSelect.testOnly()) {
appendWithoutIndent("~presence_test");
}
}
private void appendCall(CelExpr.CelCall celCall) {
indent();
appendWithNewline("function: " + celCall.function());
if (celCall.target().isPresent()) {
appendWithNewline("target: {");
indent();
formatExpr(celCall.target().get());
outdent();
appendNewline();
appendWithNewline("}");
}
append("args: {");
indent();
for (CelExpr celExpr : celCall.args()) {
appendNewline();
formatExpr(celExpr);
}
outdent();
appendNewline();
append("}");
outdent();
}
private void appendList(CelExpr.CelList celList) {
indent();
append("elements: {");
indent();
for (CelExpr expr : celList.elements()) {
appendNewline();
formatExpr(expr);
}
outdent();
appendNewline();
append("}");
if (!celList.optionalIndices().isEmpty()) {
appendNewline();
append("optional_indices: [");
for (int i = 0; i < celList.optionalIndices().size(); i++) {
appendWithoutIndent(String.valueOf(i));
if (i != celList.optionalIndices().size() - 1) {
appendWithoutIndent(", ");
}
}
appendWithoutIndent("]");
}
outdent();
}
private void appendStruct(CelExpr.CelStruct celStruct) {
indent();
appendWithNewline("name: " + celStruct.messageName());
append("entries: {");
indent();
for (CelExpr.CelStruct.Entry entry : celStruct.entries()) {
appendNewline();
appendWithNewline(String.format("ENTRY [%d] {", entry.id()));
indent();
appendWithNewline("field_key: " + entry.fieldKey());
if (entry.optionalEntry()) {
appendWithNewline("optional_entry: true");
}
appendWithNewline("value: {");
indent();
formatExpr(entry.value());
outdent();
appendNewline();
appendWithNewline("}");
outdent();
append("}");
}
outdent();
appendNewline();
append("}");
outdent();
}
private void appendMap(CelExpr.CelMap celMap) {
indent();
boolean firstLine = true;
for (CelExpr.CelMap.Entry entry : celMap.entries()) {
if (!firstLine) {
appendNewline();
} else {
firstLine = false;
}
appendWithNewline(String.format("MAP_ENTRY [%d] {", entry.id()));
indent();
appendWithNewline("key: {");
indent();
formatExpr(entry.key());
outdent();
appendNewline();
appendWithNewline("}");
if (entry.optionalEntry()) {
appendWithNewline("optional_entry: true");
}
appendWithNewline("value: {");
indent();
formatExpr(entry.value());
outdent();
appendNewline();
appendWithNewline("}");
outdent();
append("}");
}
outdent();
}
private void appendComprehension(CelExpr.CelComprehension celComprehension) {
indent();
appendWithNewline("iter_var: " + celComprehension.iterVar());
// Iter range
appendWithNewline("iter_range: {");
indent();
formatExpr(celComprehension.iterRange());
outdent();
appendNewline();
appendWithNewline("}");
appendWithNewline("accu_var: " + celComprehension.accuVar());
// Accu init
appendWithNewline("accu_init: {");
indent();
formatExpr(celComprehension.accuInit());
outdent();
appendNewline();
appendWithNewline("}");
// Loop condition
appendWithNewline("loop_condition: {");
indent();
formatExpr(celComprehension.loopCondition());
outdent();
appendNewline();
appendWithNewline("}");
// Loop step
appendWithNewline("loop_step: {");
indent();
formatExpr(celComprehension.loopStep());
outdent();
appendNewline();
appendWithNewline("}");
// Result
appendWithNewline("result: {");
indent();
formatExpr(celComprehension.result());
outdent();
appendNewline();
append("}");
outdent();
}
private void append(String str) {
exprBuilder.append(indent);
exprBuilder.append(str);
}
private void appendWithNewline(String str) {
append(str);
appendNewline();
}
private void appendWithoutIndent(String str) {
exprBuilder.append(str);
}
private void appendNewline() {
exprBuilder.append('\n');
}
private void indent() {
indent.append(" ");
}
private void outdent() {
indent.setLength(indent.length() - 2);
}
private CelExprFormatter() {}
}