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Merged
nscuro merged 1 commit into from
Oct 18, 2026
Merged

Handle leading whitespace in BOM detection #957

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40 changes: 32 additions & 8 deletions src/main/java/org/cyclonedx/parsers/BomParserFactory.java
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Original file line number Diff line number Diff line change
Expand Up @@ -20,19 +20,19 @@

import org.cyclonedx.exception.ParseException;

import java.io.BufferedInputStream;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.nio.charset.StandardCharsets;
import java.nio.file.Files;
import java.util.Arrays;

public class BomParserFactory {

private BomParserFactory() {}

public static Parser createParser(final File file) throws ParseException {
try (final InputStream fis = Files.newInputStream(file.toPath())) {
try (final InputStream fis = new BufferedInputStream(Files.newInputStream(file.toPath()))) {
final byte[] prefix = new byte[4]; // potential 3-byte UTF-8 byte-order mark + 1 content byte
int actualPrefixLength = 0;
while (actualPrefixLength < prefix.length) {
Expand All @@ -42,29 +42,41 @@ public static Parser createParser(final File file) throws ParseException {
}
actualPrefixLength += read;
}
return createParser(Arrays.copyOf(prefix, actualPrefixLength));
final int offset = firstContentOffset(prefix, actualPrefixLength);
if (offset < actualPrefixLength) {
return createParserForContentByte(prefix[offset] & 0xFF);
}
int contentByte;
do {
contentByte = fis.read();
} while (isWhitespace(contentByte));
return createParserForContentByte(contentByte);
} catch (IOException e) {
throw new ParseException("An error occurred creating parser from file", e);
}
}

public static Parser createParser(final byte[] bytes) throws ParseException {
final int offset = hasUtf8ByteOrderMark(bytes) ? 3 : 0;
if (bytes.length - offset < 1) {
final int offset = firstContentOffset(bytes, bytes.length);
return createParserForContentByte(offset < bytes.length ? bytes[offset] & 0xFF : -1);
}

private static Parser createParserForContentByte(final int contentByte) throws ParseException {
if (contentByte == -1) {
throw new ParseException("Cannot create parser from empty byte array.");
}

if (bytes[offset] == (byte) '{') {
if (contentByte == '{') {
return new JsonParser();
} else if (bytes[offset] == (byte) '<') {
} else if (contentByte == '<') {
return new XmlParser();
} else {
throw new ParseException("The specified BOM is not in a supported format. Supported formats are XML and JSON");
}
}

public static boolean looksLikeCycloneDX(final byte[] bytes) {
final int offset = hasUtf8ByteOrderMark(bytes) ? 3 : 0;
final int offset = firstContentOffset(bytes, bytes.length);
final String bomString = new String(bytes, offset, bytes.length - offset, StandardCharsets.UTF_8);
if (bomString.startsWith("<?xml") && bomString.contains("<bom") &&
bomString.contains("http://cyclonedx.org/schema/bom")) {
Expand All @@ -75,6 +87,18 @@ public static boolean looksLikeCycloneDX(final byte[] bytes) {
}
}

private static int firstContentOffset(final byte[] bytes, final int length) {
int offset = length >= 3 && hasUtf8ByteOrderMark(bytes) ? 3 : 0;
while (offset < length && isWhitespace(bytes[offset])) {
offset++;
}
return offset;
}

private static boolean isWhitespace(final int value) {
return value == ' ' || value == '\t' || value == '\r' || value == '\n';
}

private static boolean hasUtf8ByteOrderMark(byte[] bytes) {
return bytes.length >= 3
&& bytes[0] == (byte) 0xEF
Expand Down
52 changes: 52 additions & 0 deletions src/test/java/org/cyclonedx/BomParserFactoryTest.java
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Original file line number Diff line number Diff line change
Expand Up @@ -24,16 +24,68 @@
import org.cyclonedx.parsers.Parser;
import org.cyclonedx.parsers.XmlParser;
import org.junit.jupiter.api.Test;
import org.junit.jupiter.api.io.TempDir;
import org.junit.jupiter.params.ParameterizedTest;
import org.junit.jupiter.params.provider.ValueSource;

import java.io.File;
import java.nio.charset.StandardCharsets;
import java.nio.file.Files;
import java.nio.file.Path;

import static java.util.Objects.requireNonNull;
import static org.junit.jupiter.api.Assertions.assertInstanceOf;
import static org.junit.jupiter.api.Assertions.assertEquals;
import static org.junit.jupiter.api.Assertions.assertFalse;
import static org.junit.jupiter.api.Assertions.assertThrows;
import static org.junit.jupiter.api.Assertions.assertTrue;

public class BomParserFactoryTest {

@TempDir
Path tempDir;

@ParameterizedTest
@ValueSource(strings = {"", "\n", " \t\r\n", "\uFEFF", "\uFEFF \r\n"})
void testJsonWithLeadingWhitespace(String prefix) throws Exception {
byte[] bytes = (prefix + "{\"bomFormat\":\"CycloneDX\",\"specVersion\":\"1.6\",\"version\":1}")
.getBytes(StandardCharsets.UTF_8);
Parser parser = BomParserFactory.createParser(bytes);
assertInstanceOf(JsonParser.class, parser);
assertEquals(1, parser.parse(bytes).getVersion());
assertTrue(BomParserFactory.looksLikeCycloneDX(bytes));

File file = Files.write(tempDir.resolve("bom.json"), bytes).toFile();
Parser fileParser = BomParserFactory.createParser(file);
assertInstanceOf(JsonParser.class, fileParser);
assertEquals(1, fileParser.parse(file).getVersion());
}

@ParameterizedTest
@ValueSource(strings = {"", "\n", " \t\r\n", "\uFEFF", "\uFEFF \r\n"})
void testXmlWithLeadingWhitespace(String prefix) throws Exception {
byte[] bytes = (prefix + "<bom xmlns=\"http://cyclonedx.org/schema/bom/1.6\" version=\"1\"/>")
.getBytes(StandardCharsets.UTF_8);
Parser parser = BomParserFactory.createParser(bytes);
assertInstanceOf(XmlParser.class, parser);
assertEquals(1, parser.parse(bytes).getVersion());

File file = Files.write(tempDir.resolve("bom.xml"), bytes).toFile();
Parser fileParser = BomParserFactory.createParser(file);
assertInstanceOf(XmlParser.class, fileParser);
assertEquals(1, fileParser.parse(file).getVersion());
}

@ParameterizedTest
@ValueSource(strings = {"", " \t\r\n", "\uFEFF", "\uFEFF \n", "x{}", " \u000B{}"})
void testRejectsEmptyOrUnsupportedContent(String content) throws Exception {
byte[] bytes = content.getBytes(StandardCharsets.UTF_8);
assertThrows(ParseException.class, () -> BomParserFactory.createParser(bytes));
assertFalse(BomParserFactory.looksLikeCycloneDX(bytes));
File file = Files.write(tempDir.resolve("unsupported"), bytes).toFile();
assertThrows(ParseException.class, () -> BomParserFactory.createParser(file));
}

@Test
public void testXMLFactory() throws Exception {
Parser parser = BomParserFactory.createParser(
Expand Down
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