com.facebook.presto.jdbc.internal.okio.BufferedSource Maven / Gradle / Ivy
/*
* Copyright (C) 2014 Square, Inc.
*
* 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.facebook.presto.jdbc.internal.okio;
import java.io.IOException;
import java.io.InputStream;
import java.nio.charset.Charset;
import com.facebook.presto.jdbc.internal.javax.annotation.Nullable;
/**
* A source that keeps a buffer internally so that callers can do small reads without a performance
* penalty. It also allows clients to read ahead, buffering as much as necessary before consuming
* input.
*/
public interface BufferedSource extends Source {
/** Returns this source's internal buffer. */
Buffer buffer();
/**
* Returns true if there are no more bytes in this source. This will block until there are bytes
* to read or the source is definitely exhausted.
*/
boolean exhausted() throws IOException;
/**
* Returns when the buffer contains at least {@code byteCount} bytes. Throws an
* {@link java.io.EOFException} if the source is exhausted before the required bytes can be read.
*/
void require(long byteCount) throws IOException;
/**
* Returns true when the buffer contains at least {@code byteCount} bytes, expanding it as
* necessary. Returns false if the source is exhausted before the requested bytes can be read.
*/
boolean request(long byteCount) throws IOException;
/** Removes a byte from this source and returns it. */
byte readByte() throws IOException;
/**
* Removes two bytes from this source and returns a big-endian short. {@code
*
* Buffer buffer = new Buffer()
* .writeByte(0x7f)
* .writeByte(0xff)
* .writeByte(0x00)
* .writeByte(0x0f);
* assertEquals(4, buffer.size());
*
* assertEquals(32767, buffer.readShort());
* assertEquals(2, buffer.size());
*
* assertEquals(15, buffer.readShort());
* assertEquals(0, buffer.size());
* }
*/
short readShort() throws IOException;
/**
* Removes two bytes from this source and returns a little-endian short. {@code
*
* Buffer buffer = new Buffer()
* .writeByte(0xff)
* .writeByte(0x7f)
* .writeByte(0x0f)
* .writeByte(0x00);
* assertEquals(4, buffer.size());
*
* assertEquals(32767, buffer.readShortLe());
* assertEquals(2, buffer.size());
*
* assertEquals(15, buffer.readShortLe());
* assertEquals(0, buffer.size());
* }
*/
short readShortLe() throws IOException;
/**
* Removes four bytes from this source and returns a big-endian int. {@code
*
* Buffer buffer = new Buffer()
* .writeByte(0x7f)
* .writeByte(0xff)
* .writeByte(0xff)
* .writeByte(0xff)
* .writeByte(0x00)
* .writeByte(0x00)
* .writeByte(0x00)
* .writeByte(0x0f);
* assertEquals(8, buffer.size());
*
* assertEquals(2147483647, buffer.readInt());
* assertEquals(4, buffer.size());
*
* assertEquals(15, buffer.readInt());
* assertEquals(0, buffer.size());
* }
*/
int readInt() throws IOException;
/**
* Removes four bytes from this source and returns a little-endian int. {@code
*
* Buffer buffer = new Buffer()
* .writeByte(0xff)
* .writeByte(0xff)
* .writeByte(0xff)
* .writeByte(0x7f)
* .writeByte(0x0f)
* .writeByte(0x00)
* .writeByte(0x00)
* .writeByte(0x00);
* assertEquals(8, buffer.size());
*
* assertEquals(2147483647, buffer.readIntLe());
* assertEquals(4, buffer.size());
*
* assertEquals(15, buffer.readIntLe());
* assertEquals(0, buffer.size());
* }
*/
int readIntLe() throws IOException;
/**
* Removes eight bytes from this source and returns a big-endian long. {@code
*
* Buffer buffer = new Buffer()
* .writeByte(0x7f)
* .writeByte(0xff)
* .writeByte(0xff)
* .writeByte(0xff)
* .writeByte(0xff)
* .writeByte(0xff)
* .writeByte(0xff)
* .writeByte(0xff)
* .writeByte(0x00)
* .writeByte(0x00)
* .writeByte(0x00)
* .writeByte(0x00)
* .writeByte(0x00)
* .writeByte(0x00)
* .writeByte(0x00)
* .writeByte(0x0f);
* assertEquals(16, buffer.size());
*
* assertEquals(9223372036854775807L, buffer.readLong());
* assertEquals(8, buffer.size());
*
* assertEquals(15, buffer.readLong());
* assertEquals(0, buffer.size());
* }
*/
long readLong() throws IOException;
/**
* Removes eight bytes from this source and returns a little-endian long. {@code
*
* Buffer buffer = new Buffer()
* .writeByte(0xff)
* .writeByte(0xff)
* .writeByte(0xff)
* .writeByte(0xff)
* .writeByte(0xff)
* .writeByte(0xff)
* .writeByte(0xff)
* .writeByte(0x7f)
* .writeByte(0x0f)
* .writeByte(0x00)
* .writeByte(0x00)
* .writeByte(0x00)
* .writeByte(0x00)
* .writeByte(0x00)
* .writeByte(0x00)
* .writeByte(0x00);
* assertEquals(16, buffer.size());
*
* assertEquals(9223372036854775807L, buffer.readLongLe());
* assertEquals(8, buffer.size());
*
* assertEquals(15, buffer.readLongLe());
* assertEquals(0, buffer.size());
* }
*/
long readLongLe() throws IOException;
/**
* Reads a long from this source in signed decimal form (i.e., as a string in base 10 with
* optional leading '-'). This will iterate until a non-digit character is found. {@code
*
* Buffer buffer = new Buffer()
* .writeUtf8("8675309 -123 00001");
*
* assertEquals(8675309L, buffer.readDecimalLong());
* assertEquals(' ', buffer.readByte());
* assertEquals(-123L, buffer.readDecimalLong());
* assertEquals(' ', buffer.readByte());
* assertEquals(1L, buffer.readDecimalLong());
* }
*
* @throws NumberFormatException if the found digits do not fit into a {@code long} or a decimal
* number was not present.
*/
long readDecimalLong() throws IOException;
/**
* Reads a long form this source in hexadecimal form (i.e., as a string in base 16). This will
* iterate until a non-hexadecimal character is found. {@code
*
* Buffer buffer = new Buffer()
* .writeUtf8("ffff CAFEBABE 10");
*
* assertEquals(65535L, buffer.readHexadecimalUnsignedLong());
* assertEquals(' ', buffer.readByte());
* assertEquals(0xcafebabeL, buffer.readHexadecimalUnsignedLong());
* assertEquals(' ', buffer.readByte());
* assertEquals(0x10L, buffer.readHexadecimalUnsignedLong());
* }
*
* @throws NumberFormatException if the found hexadecimal does not fit into a {@code long} or
* hexadecimal was not found.
*/
long readHexadecimalUnsignedLong() throws IOException;
/**
* Reads and discards {@code byteCount} bytes from this source. Throws an
* {@link java.io.EOFException} if the source is exhausted before the
* requested bytes can be skipped.
*/
void skip(long byteCount) throws IOException;
/** Removes all bytes bytes from this and returns them as a byte string. */
ByteString readByteString() throws IOException;
/** Removes {@code byteCount} bytes from this and returns them as a byte string. */
ByteString readByteString(long byteCount) throws IOException;
/**
* Finds the first string in {@code options} that is a prefix of this buffer, consumes it from
* this buffer, and returns its index. If no byte string in {@code options} is a prefix of this
* buffer this returns -1 and no bytes are consumed.
*
* This can be used as an alternative to {@link #readByteString} or even {@link #readUtf8} if
* the set of expected values is known in advance.
{@code
*
* Options FIELDS = Options.of(
* ByteString.encodeUtf8("depth="),
* ByteString.encodeUtf8("height="),
* ByteString.encodeUtf8("width="));
*
* Buffer buffer = new Buffer()
* .writeUtf8("width=640\n")
* .writeUtf8("height=480\n");
*
* assertEquals(2, buffer.select(FIELDS));
* assertEquals(640, buffer.readDecimalLong());
* assertEquals('\n', buffer.readByte());
* assertEquals(1, buffer.select(FIELDS));
* assertEquals(480, buffer.readDecimalLong());
* assertEquals('\n', buffer.readByte());
* }
*/
int select(Options options) throws IOException;
/** Removes all bytes from this and returns them as a byte array. */
byte[] readByteArray() throws IOException;
/** Removes {@code byteCount} bytes from this and returns them as a byte array. */
byte[] readByteArray(long byteCount) throws IOException;
/**
* Removes up to {@code sink.length} bytes from this and copies them into {@code sink}. Returns
* the number of bytes read, or -1 if this source is exhausted.
*/
int read(byte[] sink) throws IOException;
/**
* Removes exactly {@code sink.length} bytes from this and copies them into {@code sink}. Throws
* an {@link java.io.EOFException} if the requested number of bytes cannot be read.
*/
void readFully(byte[] sink) throws IOException;
/**
* Removes up to {@code byteCount} bytes from this and copies them into {@code sink} at {@code
* offset}. Returns the number of bytes read, or -1 if this source is exhausted.
*/
int read(byte[] sink, int offset, int byteCount) throws IOException;
/**
* Removes exactly {@code byteCount} bytes from this and appends them to {@code sink}. Throws an
* {@link java.io.EOFException} if the requested number of bytes cannot be read.
*/
void readFully(Buffer sink, long byteCount) throws IOException;
/**
* Removes all bytes from this and appends them to {@code sink}. Returns the total number of bytes
* written to {@code sink} which will be 0 if this is exhausted.
*/
long readAll(Sink sink) throws IOException;
/**
* Removes all bytes from this, decodes them as UTF-8, and returns the string. Returns the empty
* string if this source is empty. {@code
*
* Buffer buffer = new Buffer()
* .writeUtf8("Uh uh uh!")
* .writeByte(' ')
* .writeUtf8("You didn't say the magic word!");
*
* assertEquals("Uh uh uh! You didn't say the magic word!", buffer.readUtf8());
* assertEquals(0, buffer.size());
*
* assertEquals("", buffer.readUtf8());
* assertEquals(0, buffer.size());
* }
*/
String readUtf8() throws IOException;
/**
* Removes {@code byteCount} bytes from this, decodes them as UTF-8, and returns the string.
* {@code
*
* Buffer buffer = new Buffer()
* .writeUtf8("Uh uh uh!")
* .writeByte(' ')
* .writeUtf8("You didn't say the magic word!");
* assertEquals(40, buffer.size());
*
* assertEquals("Uh uh uh! You ", buffer.readUtf8(14));
* assertEquals(26, buffer.size());
*
* assertEquals("didn't say the", buffer.readUtf8(14));
* assertEquals(12, buffer.size());
*
* assertEquals(" magic word!", buffer.readUtf8(12));
* assertEquals(0, buffer.size());
* }
*/
String readUtf8(long byteCount) throws IOException;
/**
* Removes and returns characters up to but not including the next line break. A line break is
* either {@code "\n"} or {@code "\r\n"}; these characters are not included in the result.
* {@code
*
* Buffer buffer = new Buffer()
* .writeUtf8("I'm a hacker!\n")
* .writeUtf8("That's what I said: you're a nerd.\n")
* .writeUtf8("I prefer to be called a hacker!\n");
* assertEquals(81, buffer.size());
*
* assertEquals("I'm a hacker!", buffer.readUtf8Line());
* assertEquals(67, buffer.size());
*
* assertEquals("That's what I said: you're a nerd.", buffer.readUtf8Line());
* assertEquals(32, buffer.size());
*
* assertEquals("I prefer to be called a hacker!", buffer.readUtf8Line());
* assertEquals(0, buffer.size());
*
* assertEquals(null, buffer.readUtf8Line());
* assertEquals(0, buffer.size());
* }
*
* On the end of the stream this method returns null, just like {@link
* java.io.BufferedReader}. If the source doesn't end with a line break then an implicit line
* break is assumed. Null is returned once the source is exhausted. Use this for human-generated
* data, where a trailing line break is optional.
*/
@Nullable String readUtf8Line() throws IOException;
/**
* Removes and returns characters up to but not including the next line break. A line break is
* either {@code "\n"} or {@code "\r\n"}; these characters are not included in the result.
*
*
On the end of the stream this method throws. Every call must consume either
* '\r\n' or '\n'. If these characters are absent in the stream, an {@link java.io.EOFException}
* is thrown. Use this for machine-generated data where a missing line break implies truncated
* input.
*/
String readUtf8LineStrict() throws IOException;
/**
* Like {@link #readUtf8LineStrict()}, except this allows the caller to specify the longest
* allowed match. Use this to protect against streams that may not include
* {@code "\n"} or {@code "\r\n"}.
*
*
The returned string will have at most {@code limit} UTF-8 bytes, and the maximum number
* of bytes scanned is {@code limit + 2}. If {@code limit == 0} this will always throw
* an {@code EOFException} because no bytes will be scanned.
*
*
This method is safe. No bytes are discarded if the match fails, and the caller is free
* to try another match:
{@code
*
* Buffer buffer = new Buffer();
* buffer.writeUtf8("12345\r\n");
*
* // This will throw! There must be \r\n or \n at the limit or before it.
* buffer.readUtf8LineStrict(4);
*
* // No bytes have been consumed so the caller can retry.
* assertEquals("12345", buffer.readUtf8LineStrict(5));
* }
*/
String readUtf8LineStrict(long limit) throws IOException;
/**
* Removes and returns a single UTF-8 code point, reading between 1 and 4 bytes as necessary.
*
* If this source is exhausted before a complete code point can be read, this throws an {@link
* java.io.EOFException} and consumes no input.
*
*
If this source doesn't start with a properly-encoded UTF-8 code point, this method will
* remove 1 or more non-UTF-8 bytes and return the replacement character ({@code U+FFFD}). This
* covers encoding problems (the input is not properly-encoded UTF-8), characters out of range
* (beyond the 0x10ffff limit of Unicode), code points for UTF-16 surrogates (U+d800..U+dfff) and
* overlong encodings (such as {@code 0xc080} for the NUL character in modified UTF-8).
*/
int readUtf8CodePoint() throws IOException;
/** Removes all bytes from this, decodes them as {@code charset}, and returns the string. */
String readString(Charset charset) throws IOException;
/**
* Removes {@code byteCount} bytes from this, decodes them as {@code charset}, and returns the
* string.
*/
String readString(long byteCount, Charset charset) throws IOException;
/** Equivalent to {@link #indexOf(byte, long) indexOf(b, 0)}. */
long indexOf(byte b) throws IOException;
/**
* Returns the index of the first {@code b} in the buffer at or after {@code fromIndex}. This
* expands the buffer as necessary until {@code b} is found. This reads an unbounded number of
* bytes into the buffer. Returns -1 if the stream is exhausted before the requested byte is
* found.
{@code
*
* Buffer buffer = new Buffer();
* buffer.writeUtf8("Don't move! He can't see us if we don't move.");
*
* byte m = 'm';
* assertEquals(6, buffer.indexOf(m));
* assertEquals(40, buffer.indexOf(m, 12));
* }
*/
long indexOf(byte b, long fromIndex) throws IOException;
/**
* Returns the index of {@code b} if it is found in the range of {@code fromIndex} inclusive
* to {@code toIndex} exclusive. If {@code b} isn't found, or if {@code fromIndex == toIndex},
* then -1 is returned.
*
* The scan terminates at either {@code toIndex} or the end of the buffer, whichever comes
* first. The maximum number of bytes scanned is {@code toIndex-fromIndex}.
*/
long indexOf(byte b, long fromIndex, long toIndex) throws IOException;
/** Equivalent to {@link #indexOf(ByteString, long) indexOf(bytes, 0)}. */
long indexOf(ByteString bytes) throws IOException;
/**
* Returns the index of the first match for {@code bytes} in the buffer at or after {@code
* fromIndex}. This expands the buffer as necessary until {@code bytes} is found. This reads an
* unbounded number of bytes into the buffer. Returns -1 if the stream is exhausted before the
* requested bytes are found.
{@code
*
* ByteString MOVE = ByteString.encodeUtf8("move");
*
* Buffer buffer = new Buffer();
* buffer.writeUtf8("Don't move! He can't see us if we don't move.");
*
* assertEquals(6, buffer.indexOf(MOVE));
* assertEquals(40, buffer.indexOf(MOVE, 12));
* }
*/
long indexOf(ByteString bytes, long fromIndex) throws IOException;
/** Equivalent to {@link #indexOfElement(ByteString, long) indexOfElement(targetBytes, 0)}. */
long indexOfElement(ByteString targetBytes) throws IOException;
/**
* Returns the first index in this buffer that is at or after {@code fromIndex} and that contains
* any of the bytes in {@code targetBytes}. This expands the buffer as necessary until a target
* byte is found. This reads an unbounded number of bytes into the buffer. Returns -1 if the
* stream is exhausted before the requested byte is found. {@code
*
* ByteString ANY_VOWEL = ByteString.encodeUtf8("AEOIUaeoiu");
*
* Buffer buffer = new Buffer();
* buffer.writeUtf8("Dr. Alan Grant");
*
* assertEquals(4, buffer.indexOfElement(ANY_VOWEL)); // 'A' in 'Alan'.
* assertEquals(11, buffer.indexOfElement(ANY_VOWEL, 9)); // 'a' in 'Grant'.
* }
*/
long indexOfElement(ByteString targetBytes, long fromIndex) throws IOException;
/**
* Returns true if the bytes at {@code offset} in this source equal {@code bytes}. This expands
* the buffer as necessary until a byte does not match, all bytes are matched, or if the stream
* is exhausted before enough bytes could determine a match. {@code
*
* ByteString simonSays = ByteString.encodeUtf8("Simon says:");
*
* Buffer standOnOneLeg = new Buffer().writeUtf8("Simon says: Stand on one leg.");
* assertTrue(standOnOneLeg.rangeEquals(0, simonSays));
*
* Buffer payMeMoney = new Buffer().writeUtf8("Pay me $1,000,000.");
* assertFalse(payMeMoney.rangeEquals(0, simonSays));
* }
*/
boolean rangeEquals(long offset, ByteString bytes) throws IOException;
/**
* Returns true if {@code byteCount} bytes at {@code offset} in this source equal {@code bytes}
* at {@code bytesOffset}. This expands the buffer as necessary until a byte does not match, all
* bytes are matched, or if the stream is exhausted before enough bytes could determine a match.
*/
boolean rangeEquals(long offset, ByteString bytes, int bytesOffset, int byteCount)
throws IOException;
/** Returns an input stream that reads from this source. */
InputStream inputStream();
}