Adam Lesinski | 21efb68 | 2016-09-14 17:35:43 -0700 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2016 The Android Open Source Project |
| 3 | * |
| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | * you may not use this file except in compliance with the License. |
| 6 | * You may obtain a copy of the License at |
| 7 | * |
| 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | * |
| 10 | * Unless required by applicable law or agreed to in writing, software |
| 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | * See the License for the specific language governing permissions and |
| 14 | * limitations under the License. |
| 15 | */ |
| 16 | |
| 17 | #ifndef AAPT_IO_IO_H |
| 18 | #define AAPT_IO_IO_H |
| 19 | |
Adam Lesinski | 21efb68 | 2016-09-14 17:35:43 -0700 | [diff] [blame] | 20 | #include <string> |
| 21 | |
| 22 | namespace aapt { |
| 23 | namespace io { |
| 24 | |
Adam Lesinski | 06460ef | 2017-03-14 18:52:13 -0700 | [diff] [blame] | 25 | // InputStream interface that mimics protobuf's ZeroCopyInputStream, |
| 26 | // with added error handling methods to better report issues. |
| 27 | class InputStream { |
Adam Lesinski | cacb28f | 2016-10-19 12:18:14 -0700 | [diff] [blame] | 28 | public: |
Adam Lesinski | 06460ef | 2017-03-14 18:52:13 -0700 | [diff] [blame] | 29 | virtual ~InputStream() = default; |
| 30 | |
| 31 | // Returns a chunk of data for reading. data and size must not be nullptr. |
| 32 | // Returns true so long as there is more data to read, returns false if an error occurred |
| 33 | // or no data remains. If an error occurred, check HadError(). |
| 34 | // The stream owns the buffer returned from this method and the buffer is invalidated |
| 35 | // anytime another mutable method is called. |
| 36 | virtual bool Next(const void** data, size_t* size) = 0; |
| 37 | |
| 38 | // Backup count bytes, where count is smaller or equal to the size of the last buffer returned |
| 39 | // from Next(). |
| 40 | // Useful when the last block returned from Next() wasn't fully read. |
| 41 | virtual void BackUp(size_t count) = 0; |
| 42 | |
| 43 | // Returns true if this InputStream can rewind. If so, Rewind() can be called. |
| 44 | virtual bool CanRewind() const { return false; }; |
| 45 | |
| 46 | // Rewinds the stream to the beginning so it can be read again. |
| 47 | // Returns true if the rewind succeeded. |
| 48 | // This does nothing if CanRewind() returns false. |
| 49 | virtual bool Rewind() { return false; } |
| 50 | |
| 51 | // Returns the number of bytes that have been read from the stream. |
| 52 | virtual size_t ByteCount() const = 0; |
| 53 | |
| 54 | // Returns an error message if HadError() returned true. |
Adam Lesinski | cacb28f | 2016-10-19 12:18:14 -0700 | [diff] [blame] | 55 | virtual std::string GetError() const { return {}; } |
Adam Lesinski | 21efb68 | 2016-09-14 17:35:43 -0700 | [diff] [blame] | 56 | |
Adam Lesinski | 06460ef | 2017-03-14 18:52:13 -0700 | [diff] [blame] | 57 | // Returns true if an error occurred. Errors are permanent. |
Adam Lesinski | cacb28f | 2016-10-19 12:18:14 -0700 | [diff] [blame] | 58 | virtual bool HadError() const = 0; |
Adam Lesinski | 21efb68 | 2016-09-14 17:35:43 -0700 | [diff] [blame] | 59 | }; |
| 60 | |
Adam Lesinski | 06460ef | 2017-03-14 18:52:13 -0700 | [diff] [blame] | 61 | // OutputStream interface that mimics protobuf's ZeroCopyOutputStream, |
| 62 | // with added error handling methods to better report issues. |
| 63 | class OutputStream { |
Adam Lesinski | cacb28f | 2016-10-19 12:18:14 -0700 | [diff] [blame] | 64 | public: |
Adam Lesinski | 06460ef | 2017-03-14 18:52:13 -0700 | [diff] [blame] | 65 | virtual ~OutputStream() = default; |
| 66 | |
| 67 | // Returns a buffer to which data can be written to. The data written to this buffer will |
| 68 | // eventually be written to the stream. Call BackUp() if the data written doesn't occupy the |
| 69 | // entire buffer. |
| 70 | // Return false if there was an error. |
| 71 | // The stream owns the buffer returned from this method and the buffer is invalidated |
| 72 | // anytime another mutable method is called. |
| 73 | virtual bool Next(void** data, size_t* size) = 0; |
| 74 | |
| 75 | // Backup count bytes, where count is smaller or equal to the size of the last buffer returned |
| 76 | // from Next(). |
| 77 | // Useful for when the last block returned from Next() wasn't fully written to. |
| 78 | virtual void BackUp(size_t count) = 0; |
| 79 | |
| 80 | // Returns the number of bytes that have been written to the stream. |
| 81 | virtual size_t ByteCount() const = 0; |
| 82 | |
| 83 | // Returns an error message if HadError() returned true. |
Adam Lesinski | cacb28f | 2016-10-19 12:18:14 -0700 | [diff] [blame] | 84 | virtual std::string GetError() const { return {}; } |
Adam Lesinski | 21efb68 | 2016-09-14 17:35:43 -0700 | [diff] [blame] | 85 | |
Adam Lesinski | 06460ef | 2017-03-14 18:52:13 -0700 | [diff] [blame] | 86 | // Returns true if an error occurred. Errors are permanent. |
Adam Lesinski | cacb28f | 2016-10-19 12:18:14 -0700 | [diff] [blame] | 87 | virtual bool HadError() const = 0; |
Adam Lesinski | 21efb68 | 2016-09-14 17:35:43 -0700 | [diff] [blame] | 88 | }; |
| 89 | |
Adam Lesinski | cacb28f | 2016-10-19 12:18:14 -0700 | [diff] [blame] | 90 | } // namespace io |
| 91 | } // namespace aapt |
Adam Lesinski | 21efb68 | 2016-09-14 17:35:43 -0700 | [diff] [blame] | 92 | |
| 93 | #endif /* AAPT_IO_IO_H */ |