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Diffstat (limited to 'java/src/main/java/com/google/protobuf/CodedInputStream.java')
| -rw-r--r-- | java/src/main/java/com/google/protobuf/CodedInputStream.java | 766 |
1 files changed, 766 insertions, 0 deletions
diff --git a/java/src/main/java/com/google/protobuf/CodedInputStream.java b/java/src/main/java/com/google/protobuf/CodedInputStream.java new file mode 100644 index 00000000..b32c349c --- /dev/null +++ b/java/src/main/java/com/google/protobuf/CodedInputStream.java @@ -0,0 +1,766 @@ +// Protocol Buffers - Google's data interchange format +// Copyright 2008 Google Inc. +// http://code.google.com/p/protobuf/ +// +// 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 com.google.protobuf; + +import java.io.IOException; +import java.io.InputStream; +import java.util.ArrayList; +import java.util.List; + +/** + * Reads and decodes protocol message fields. + * + * This class contains two kinds of methods: methods that read specific + * protocol message constructs and field types (e.g. {@link #readTag()} and + * {@link #readInt32()}) and methods that read low-level values (e.g. + * {@link #readRawVarint32()} and {@link #readRawBytes}). If you are reading + * encoded protocol messages, you should use the former methods, but if you are + * reading some other format of your own design, use the latter. + * + * @author kenton@google.com Kenton Varda + */ +public final class CodedInputStream { + /** + * Create a new CodedInputStream wrapping the given InputStream. + */ + public static CodedInputStream newInstance(InputStream input) { + return new CodedInputStream(input); + } + + /** + * Create a new CodedInputStream wrapping the given byte array. + */ + public static CodedInputStream newInstance(byte[] buf) { + return new CodedInputStream(buf); + } + + // ----------------------------------------------------------------- + + /** + * Attempt to read a field tag, returning zero if we have reached EOF. + * Protocol message parsers use this to read tags, since a protocol message + * may legally end wherever a tag occurs, and zero is not a valid tag number. + */ + public int readTag() throws IOException { + if (bufferPos == bufferSize && !refillBuffer(false)) { + lastTag = 0; + return 0; + } + + lastTag = readRawVarint32(); + if (lastTag == 0) { + // If we actually read zero, that's not a valid tag. + throw InvalidProtocolBufferException.invalidTag(); + } + return lastTag; + } + + /** + * Verifies that the last call to readTag() returned the given tag value. + * This is used to verify that a nested group ended with the correct + * end tag. + * + * @throws InvalidProtocolBufferException {@code value} does not match the + * last tag. + */ + public void checkLastTagWas(int value) throws InvalidProtocolBufferException { + if (lastTag != value) { + throw InvalidProtocolBufferException.invalidEndTag(); + } + } + + /** + * Reads and discards a single field, given its tag value. + * + * @return {@code false} if the tag is an endgroup tag, in which case + * nothing is skipped. Otherwise, returns {@code true}. + */ + public boolean skipField(int tag) throws IOException { + switch (WireFormat.getTagWireType(tag)) { + case WireFormat.WIRETYPE_VARINT: + readInt32(); + return true; + case WireFormat.WIRETYPE_FIXED64: + readRawLittleEndian64(); + return true; + case WireFormat.WIRETYPE_LENGTH_DELIMITED: + skipRawBytes(readRawVarint32()); + return true; + case WireFormat.WIRETYPE_START_GROUP: + skipMessage(); + checkLastTagWas( + WireFormat.makeTag(WireFormat.getTagFieldNumber(tag), + WireFormat.WIRETYPE_END_GROUP)); + return true; + case WireFormat.WIRETYPE_END_GROUP: + return false; + case WireFormat.WIRETYPE_FIXED32: + readRawLittleEndian32(); + return true; + default: + throw InvalidProtocolBufferException.invalidWireType(); + } + } + + /** + * Reads and discards an entire message. This will read either until EOF + * or until an endgroup tag, whichever comes first. + */ + public void skipMessage() throws IOException { + while (true) { + int tag = readTag(); + if (tag == 0 || !skipField(tag)) return; + } + } + + // ----------------------------------------------------------------- + + /** Read a {@code double} field value from the stream. */ + public double readDouble() throws IOException { + return Double.longBitsToDouble(readRawLittleEndian64()); + } + + /** Read a {@code float} field value from the stream. */ + public float readFloat() throws IOException { + return Float.intBitsToFloat(readRawLittleEndian32()); + } + + /** Read a {@code uint64} field value from the stream. */ + public long readUInt64() throws IOException { + return readRawVarint64(); + } + + /** Read an {@code int64} field value from the stream. */ + public long readInt64() throws IOException { + return readRawVarint64(); + } + + /** Read an {@code int32} field value from the stream. */ + public int readInt32() throws IOException { + return readRawVarint32(); + } + + /** Read a {@code fixed64} field value from the stream. */ + public long readFixed64() throws IOException { + return readRawLittleEndian64(); + } + + /** Read a {@code fixed32} field value from the stream. */ + public int readFixed32() throws IOException { + return readRawLittleEndian32(); + } + + /** Read a {@code bool} field value from the stream. */ + public boolean readBool() throws IOException { + return readRawVarint32() != 0; + } + + /** Read a {@code string} field value from the stream. */ + public String readString() throws IOException { + int size = readRawVarint32(); + if (size < bufferSize - bufferPos && size > 0) { + // Fast path: We already have the bytes in a contiguous buffer, so + // just copy directly from it. + String result = new String(buffer, bufferPos, size, "UTF-8"); + bufferPos += size; + return result; + } else { + // Slow path: Build a byte array first then copy it. + return new String(readRawBytes(size), "UTF-8"); + } + } + + /** Read a {@code group} field value from the stream. */ + public void readGroup(int fieldNumber, Message.Builder builder, + ExtensionRegistry extensionRegistry) + throws IOException { + if (recursionDepth >= recursionLimit) { + throw InvalidProtocolBufferException.recursionLimitExceeded(); + } + ++recursionDepth; + builder.mergeFrom(this, extensionRegistry); + checkLastTagWas( + WireFormat.makeTag(fieldNumber, WireFormat.WIRETYPE_END_GROUP)); + --recursionDepth; + } + + /** + * Reads a {@code group} field value from the stream and merges it into the + * given {@link UnknownFieldSet}. + */ + public void readUnknownGroup(int fieldNumber, UnknownFieldSet.Builder builder) + throws IOException { + if (recursionDepth >= recursionLimit) { + throw InvalidProtocolBufferException.recursionLimitExceeded(); + } + ++recursionDepth; + builder.mergeFrom(this); + checkLastTagWas( + WireFormat.makeTag(fieldNumber, WireFormat.WIRETYPE_END_GROUP)); + --recursionDepth; + } + + /** Read an embedded message field value from the stream. */ + public void readMessage(Message.Builder builder, + ExtensionRegistry extensionRegistry) + throws IOException { + int length = readRawVarint32(); + if (recursionDepth >= recursionLimit) { + throw InvalidProtocolBufferException.recursionLimitExceeded(); + } + int oldLimit = pushLimit(length); + ++recursionDepth; + builder.mergeFrom(this, extensionRegistry); + checkLastTagWas(0); + --recursionDepth; + popLimit(oldLimit); + } + + /** Read a {@code bytes} field value from the stream. */ + public ByteString readBytes() throws IOException { + int size = readRawVarint32(); + if (size < bufferSize - bufferPos && size > 0) { + // Fast path: We already have the bytes in a contiguous buffer, so + // just copy directly from it. + ByteString result = ByteString.copyFrom(buffer, bufferPos, size); + bufferPos += size; + return result; + } else { + // Slow path: Build a byte array first then copy it. + return ByteString.copyFrom(readRawBytes(size)); + } + } + + /** Read a {@code uint32} field value from the stream. */ + public int readUInt32() throws IOException { + return readRawVarint32(); + } + + /** + * Read an enum field value from the stream. Caller is responsible + * for converting the numeric value to an actual enum. + */ + public int readEnum() throws IOException { + return readRawVarint32(); + } + + /** Read an {@code sfixed32} field value from the stream. */ + public int readSFixed32() throws IOException { + return readRawLittleEndian32(); + } + + /** Read an {@code sfixed64} field value from the stream. */ + public long readSFixed64() throws IOException { + return readRawLittleEndian64(); + } + + /** Read an {@code sint32} field value from the stream. */ + public int readSInt32() throws IOException { + return decodeZigZag32(readRawVarint32()); + } + + /** Read an {@code sint64} field value from the stream. */ + public long readSInt64() throws IOException { + return decodeZigZag64(readRawVarint64()); + } + + /** + * Read a field of any primitive type. Enums, groups, and embedded + * messages are not handled by this method. + * + * @param type Declared type of the field. + * @return An object representing the field's value, of the exact + * type which would be returned by + * {@link Message#getField(Descriptors.FieldDescriptor)} for + * this field. + */ + public Object readPrimitiveField( + Descriptors.FieldDescriptor.Type type) throws IOException { + switch (type) { + case DOUBLE : return readDouble (); + case FLOAT : return readFloat (); + case INT64 : return readInt64 (); + case UINT64 : return readUInt64 (); + case INT32 : return readInt32 (); + case FIXED64 : return readFixed64 (); + case FIXED32 : return readFixed32 (); + case BOOL : return readBool (); + case STRING : return readString (); + case BYTES : return readBytes (); + case UINT32 : return readUInt32 (); + case SFIXED32: return readSFixed32(); + case SFIXED64: return readSFixed64(); + case SINT32 : return readSInt32 (); + case SINT64 : return readSInt64 (); + + case GROUP: + throw new IllegalArgumentException( + "readPrimitiveField() cannot handle nested groups."); + case MESSAGE: + throw new IllegalArgumentException( + "readPrimitiveField() cannot handle embedded messages."); + case ENUM: + // We don't hanlde enums because we don't know what to do if the + // value is not recognized. + throw new IllegalArgumentException( + "readPrimitiveField() cannot handle enums."); + } + + throw new RuntimeException( + "There is no way to get here, but the compiler thinks otherwise."); + } + + // ================================================================= + + /** + * Read a raw Varint from the stream. If larger than 32 bits, discard the + * upper bits. + */ + public int readRawVarint32() throws IOException { + byte tmp = readRawByte(); + if (tmp >= 0) { + return tmp; + } + int result = tmp & 0x7f; + if ((tmp = readRawByte()) >= 0) { + result |= tmp << 7; + } else { + result |= (tmp & 0x7f) << 7; + if ((tmp = readRawByte()) >= 0) { + result |= tmp << 14; + } else { + result |= (tmp & 0x7f) << 14; + if ((tmp = readRawByte()) >= 0) { + result |= tmp << 21; + } else { + result |= (tmp & 0x7f) << 21; + result |= (tmp = readRawByte()) << 28; + if (tmp < 0) { + // Discard upper 32 bits. + for (int i = 0; i < 5; i++) { + if (readRawByte() >= 0) return result; + } + throw InvalidProtocolBufferException.malformedVarint(); + } + } + } + } + return result; + } + + /** Read a raw Varint from the stream. */ + public long readRawVarint64() throws IOException { + int shift = 0; + long result = 0; + while (shift < 64) { + byte b = readRawByte(); + result |= (long)(b & 0x7F) << shift; + if ((b & 0x80) == 0) return result; + shift += 7; + } + throw InvalidProtocolBufferException.malformedVarint(); + } + + /** Read a 32-bit little-endian integer from the stream. */ + public int readRawLittleEndian32() throws IOException { + byte b1 = readRawByte(); + byte b2 = readRawByte(); + byte b3 = readRawByte(); + byte b4 = readRawByte(); + return (((int)b1 & 0xff) ) | + (((int)b2 & 0xff) << 8) | + (((int)b3 & 0xff) << 16) | + (((int)b4 & 0xff) << 24); + } + + /** Read a 64-bit little-endian integer from the stream. */ + public long readRawLittleEndian64() throws IOException { + byte b1 = readRawByte(); + byte b2 = readRawByte(); + byte b3 = readRawByte(); + byte b4 = readRawByte(); + byte b5 = readRawByte(); + byte b6 = readRawByte(); + byte b7 = readRawByte(); + byte b8 = readRawByte(); + return (((long)b1 & 0xff) ) | + (((long)b2 & 0xff) << 8) | + (((long)b3 & 0xff) << 16) | + (((long)b4 & 0xff) << 24) | + (((long)b5 & 0xff) << 32) | + (((long)b6 & 0xff) << 40) | + (((long)b7 & 0xff) << 48) | + (((long)b8 & 0xff) << 56); + } + + /** + * Decode a ZigZag-encoded 32-bit value. ZigZag encodes signed integers + * into values that can be efficiently encoded with varint. (Otherwise, + * negative values must be sign-extended to 64 bits to be varint encoded, + * thus always taking 10 bytes on the wire.) + * + * @param n An unsigned 32-bit integer, stored in a signed int because + * Java has no explicit unsigned support. + * @return A signed 32-bit integer. + */ + public static int decodeZigZag32(int n) { + return (n >>> 1) ^ -(n & 1); + } + + /** + * Decode a ZigZag-encoded 64-bit value. ZigZag encodes signed integers + * into values that can be efficiently encoded with varint. (Otherwise, + * negative values must be sign-extended to 64 bits to be varint encoded, + * thus always taking 10 bytes on the wire.) + * + * @param n An unsigned 64-bit integer, stored in a signed int because + * Java has no explicit unsigned support. + * @return A signed 64-bit integer. + */ + public static long decodeZigZag64(long n) { + return (n >>> 1) ^ -(n & 1); + } + + // ----------------------------------------------------------------- + + private byte[] buffer; + private int bufferSize; + private int bufferSizeAfterLimit = 0; + private int bufferPos = 0; + private InputStream input; + private int lastTag = 0; + + /** + * The total number of bytes read before the current buffer. The total + * bytes read up to the current position can be computed as + * {@code totalBytesRetired + bufferPos}. + */ + private int totalBytesRetired = 0; + + /** The absolute position of the end of the current message. */ + private int currentLimit = Integer.MAX_VALUE; + + /** See setRecursionLimit() */ + private int recursionDepth = 0; + private int recursionLimit = DEFAULT_RECURSION_LIMIT; + + /** See setSizeLimit() */ + private int sizeLimit = DEFAULT_SIZE_LIMIT; + + private static final int DEFAULT_RECURSION_LIMIT = 64; + private static final int DEFAULT_SIZE_LIMIT = 64 << 20; // 64MB + private static final int BUFFER_SIZE = 4096; + + private CodedInputStream(byte[] buffer) { + this.buffer = buffer; + this.bufferSize = buffer.length; + this.input = null; + } + + private CodedInputStream(InputStream input) { + this.buffer = new byte[BUFFER_SIZE]; + this.bufferSize = 0; + this.input = input; + } + + /** + * Set the maximum message recursion depth. In order to prevent malicious + * messages from causing stack overflows, {@code CodedInputStream} limits + * how deeply messages may be nested. The default limit is 64. + * + * @return the old limit. + */ + public int setRecursionLimit(int limit) { + if (limit < 0) { + throw new IllegalArgumentException( + "Recursion limit cannot be negative: " + limit); + } + int oldLimit = recursionLimit; + recursionLimit = limit; + return oldLimit; + } + + /** + * Set the maximum message size. In order to prevent malicious + * messages from exhausting memory or causing integer overflows, + * {@code CodedInputStream} limits how large a message may be. + * The default limit is 64MB. You should set this limit as small + * as you can without harming your app's functionality. Note that + * size limits only apply when reading from an {@code InputStream}, not + * when constructed around a raw byte array (nor with + * {@link ByteString#newCodedInput}). + * + * @return the old limit. + */ + public int setSizeLimit(int limit) { + if (limit < 0) { + throw new IllegalArgumentException( + "Size limit cannot be negative: " + limit); + } + int oldLimit = sizeLimit; + sizeLimit = limit; + return oldLimit; + } + + /** + * Sets {@code currentLimit} to (current position) + {@code byteLimit}. This + * is called when descending into a length-delimited embedded message. + * + * @return the old limit. + */ + public int pushLimit(int byteLimit) throws InvalidProtocolBufferException { + if (byteLimit < 0) { + throw InvalidProtocolBufferException.negativeSize(); + } + byteLimit += totalBytesRetired + bufferPos; + int oldLimit = currentLimit; + if (byteLimit > oldLimit) { + throw InvalidProtocolBufferException.truncatedMessage(); + } + currentLimit = byteLimit; + + recomputeBufferSizeAfterLimit(); + + return oldLimit; + } + + private void recomputeBufferSizeAfterLimit() { + bufferSize += bufferSizeAfterLimit; + int bufferEnd = totalBytesRetired + bufferSize; + if (bufferEnd > currentLimit) { + // Limit is in current buffer. + bufferSizeAfterLimit = bufferEnd - currentLimit; + bufferSize -= bufferSizeAfterLimit; + } else { + bufferSizeAfterLimit = 0; + } + } + + /** + * Discards the current limit, returning to the previous limit. + * + * @param oldLimit The old limit, as returned by {@code pushLimit}. + */ + public void popLimit(int oldLimit) { + currentLimit = oldLimit; + recomputeBufferSizeAfterLimit(); + } + + /** + * Called with {@code this.buffer} is empty to read more bytes from the + * input. If {@code mustSucceed} is true, refillBuffer() gurantees that + * either there will be at least one byte in the buffer when it returns + * or it will throw an exception. If {@code mustSucceed} is false, + * refillBuffer() returns false if no more bytes were available. + */ + private boolean refillBuffer(boolean mustSucceed) throws IOException { + if (bufferPos < bufferSize) { + throw new IllegalStateException( + "refillBuffer() called when buffer wasn't empty."); + } + + if (totalBytesRetired + bufferSize == currentLimit) { + // Oops, we hit a limit. + if (mustSucceed) { + throw InvalidProtocolBufferException.truncatedMessage(); + } else { + return false; + } + } + + totalBytesRetired += bufferSize; + + bufferPos = 0; + bufferSize = (input == null) ? -1 : input.read(buffer); + if (bufferSize == -1) { + bufferSize = 0; + if (mustSucceed) { + throw InvalidProtocolBufferException.truncatedMessage(); + } else { + return false; + } + } else { + recomputeBufferSizeAfterLimit(); + int totalBytesRead = + totalBytesRetired + bufferSize + bufferSizeAfterLimit; + if (totalBytesRead > sizeLimit || totalBytesRead < 0) { + throw InvalidProtocolBufferException.sizeLimitExceeded(); + } + return true; + } + } + + /** + * Read one byte from the input. + * + * @throws InvalidProtocolBufferException The end of the stream or the current + * limit was reached. + */ + public byte readRawByte() throws IOException { + if (bufferPos == bufferSize) { + refillBuffer(true); + } + return buffer[bufferPos++]; + } + + /** + * Read a fixed size of bytes from the input. + * + * @throws InvalidProtocolBufferException The end of the stream or the current + * limit was reached. + */ + public byte[] readRawBytes(int size) throws IOException { + if (size < 0) { + throw InvalidProtocolBufferException.negativeSize(); + } + + if (totalBytesRetired + bufferPos + size > currentLimit) { + // Read to the end of the stream anyway. + skipRawBytes(currentLimit - totalBytesRetired - bufferPos); + // Then fail. + throw InvalidProtocolBufferException.truncatedMessage(); + } + + if (size <= bufferSize - bufferPos) { + // We have all the bytes we need already. + byte[] bytes = new byte[size]; + System.arraycopy(buffer, bufferPos, bytes, 0, size); + bufferPos += size; + return bytes; + } else if (size < BUFFER_SIZE) { + // Reading more bytes than are in the buffer, but not an excessive number + // of bytes. We can safely allocate the resulting array ahead of time. + + // First copy what we have. + byte[] bytes = new byte[size]; + int pos = bufferSize - bufferPos; + System.arraycopy(buffer, bufferPos, bytes, 0, pos); + bufferPos = bufferSize; + + // We want to use refillBuffer() and then copy from the buffer into our + // byte array rather than reading directly into our byte array because + // the input may be unbuffered. + refillBuffer(true); + + while (size - pos > bufferSize) { + System.arraycopy(buffer, 0, bytes, pos, bufferSize); + pos += bufferSize; + bufferPos = bufferSize; + refillBuffer(true); + } + + System.arraycopy(buffer, 0, bytes, pos, size - pos); + bufferPos = size - pos; + + return bytes; + } else { + // The size is very large. For security reasons, we can't allocate the + // entire byte array yet. The size comes directly from the input, so a + // maliciously-crafted message could provide a bogus very large size in + // order to trick the app into allocating a lot of memory. We avoid this + // by allocating and reading only a small chunk at a time, so that the + // malicious message must actually *be* extremely large to cause + // problems. Meanwhile, we limit the allowed size of a message elsewhere. + + // Remember the buffer markers since we'll have to copy the bytes out of + // it later. + int originalBufferPos = bufferPos; + int originalBufferSize = bufferSize; + + // Mark the current buffer consumed. + totalBytesRetired += bufferSize; + bufferPos = 0; + bufferSize = 0; + + // Read all the rest of the bytes we need. + int sizeLeft = size - (originalBufferSize - originalBufferPos); + List<byte[]> chunks = new ArrayList<byte[]>(); + + while (sizeLeft > 0) { + byte[] chunk = new byte[Math.min(sizeLeft, BUFFER_SIZE)]; + int pos = 0; + while (pos < chunk.length) { + int n = (input == null) ? -1 : + input.read(chunk, pos, chunk.length - pos); + if (n == -1) { + throw InvalidProtocolBufferException.truncatedMessage(); + } + totalBytesRetired += n; + pos += n; + } + sizeLeft -= chunk.length; + chunks.add(chunk); + } + + // OK, got everything. Now concatenate it all into one buffer. + byte[] bytes = new byte[size]; + + // Start by copying the leftover bytes from this.buffer. + int pos = originalBufferSize - originalBufferPos; + System.arraycopy(buffer, originalBufferPos, bytes, 0, pos); + + // And now all the chunks. + for (byte[] chunk : chunks) { + System.arraycopy(chunk, 0, bytes, pos, chunk.length); + pos += chunk.length; + } + + // Done. + return bytes; + } + } + + /** + * Reads and discards {@code size} bytes. + * + * @throws InvalidProtocolBufferException The end of the stream or the current + * limit was reached. + */ + public void skipRawBytes(int size) throws IOException { + if (size < 0) { + throw InvalidProtocolBufferException.negativeSize(); + } + + if (totalBytesRetired + bufferPos + size > currentLimit) { + // Read to the end of the stream anyway. + skipRawBytes(currentLimit - totalBytesRetired - bufferPos); + // Then fail. + throw InvalidProtocolBufferException.truncatedMessage(); + } + + if (size < bufferSize - bufferPos) { + // We have all the bytes we need already. + bufferPos += size; + } else { + // Skipping more bytes than are in the buffer. First skip what we have. + int pos = bufferSize - bufferPos; + totalBytesRetired += pos; + bufferPos = 0; + bufferSize = 0; + + // Then skip directly from the InputStream for the rest. + while (pos < size) { + int n = (input == null) ? -1 : (int) input.skip(size - pos); + if (n <= 0) { + throw InvalidProtocolBufferException.truncatedMessage(); + } + pos += n; + totalBytesRetired += n; + } + } + } +} |