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Diffstat (limited to 'README.md')
| -rw-r--r-- | README.md | 87 |
1 files changed, 69 insertions, 18 deletions
@@ -1,10 +1,12 @@ **LevelDB is a fast key-value storage library written at Google that provides an ordered mapping from string keys to string values.** [](https://travis-ci.org/google/leveldb) +[](https://ci.appveyor.com/project/pwnall/leveldb) Authors: Sanjay Ghemawat (sanjay@google.com) and Jeff Dean (jeff@google.com) # Features + * Keys and values are arbitrary byte arrays. * Data is stored sorted by key. * Callers can provide a custom comparison function to override the sort order. @@ -16,15 +18,55 @@ Authors: Sanjay Ghemawat (sanjay@google.com) and Jeff Dean (jeff@google.com) * External activity (file system operations etc.) is relayed through a virtual interface so users can customize the operating system interactions. # Documentation - [LevelDB library documentation](https://github.com/google/leveldb/blob/master/doc/index.md) is online and bundled with the source code. + [LevelDB library documentation](https://github.com/google/leveldb/blob/master/doc/index.md) is online and bundled with the source code. # Limitations + * This is not a SQL database. It does not have a relational data model, it does not support SQL queries, and it has no support for indexes. * Only a single process (possibly multi-threaded) can access a particular database at a time. * There is no client-server support builtin to the library. An application that needs such support will have to wrap their own server around the library. +# Building + +This project supports [CMake](https://cmake.org/) out of the box. + +### Build for POSIX + +Quick start: + +```bash +mkdir -p build && cd build +cmake -DCMAKE_BUILD_TYPE=Release .. && cmake --build . +``` + +### Building for Windows + +First generate the Visual Studio 2017 project/solution files: + +```cmd +mkdir build +cd build +cmake -G "Visual Studio 15" .. +``` +The default default will build for x86. For 64-bit run: + +```cmd +cmake -G "Visual Studio 15 Win64" .. +``` + +To compile the Windows solution from the command-line: + +```cmd +devenv /build Debug leveldb.sln +``` + +or open leveldb.sln in Visual Studio and build from within. + +Please see the CMake documentation and `CMakeLists.txt` for more advanced usage. + # Contributing to the leveldb Project + The leveldb project welcomes contributions. leveldb's primary goal is to be a reliable and fast key/value store. Changes that are in line with the features/limitations outlined above, and meet the requirements below, @@ -32,10 +74,10 @@ will be considered. Contribution requirements: -1. **POSIX only**. We _generally_ will only accept changes that are both - compiled, and tested on a POSIX platform - usually Linux. Very small - changes will sometimes be accepted, but consider that more of an - exception than the rule. +1. **Tested platforms only**. We _generally_ will only accept changes for + platforms that are compiled and tested. This means POSIX (for Linux and + macOS) or Windows. Very small changes will sometimes be accepted, but + consider that more of an exception than the rule. 2. **Stable API**. We strive very hard to maintain a stable API. Changes that require changes for projects using leveldb _might_ be rejected without @@ -44,7 +86,16 @@ Contribution requirements: 3. **Tests**: All changes must be accompanied by a new (or changed) test, or a sufficient explanation as to why a new (or changed) test is not required. +4. **Consistent Style**: This project conforms to the + [Google C++ Style Guide](https://google.github.io/styleguide/cppguide.html). + To ensure your changes are properly formatted please run: + + ``` + clang-format -i --style=file <file> + ``` + ## Submitting a Pull Request + Before any pull request will be accepted the author must first sign a Contributor License Agreement (CLA) at https://cla.developers.google.com/. @@ -138,37 +189,37 @@ uncompressed blocks in memory, the read performance improves again: See [doc/index.md](doc/index.md) for more explanation. See [doc/impl.md](doc/impl.md) for a brief overview of the implementation. -The public interface is in include/*.h. Callers should not include or +The public interface is in include/leveldb/*.h. Callers should not include or rely on the details of any other header files in this package. Those internal APIs may be changed without warning. Guide to header files: -* **include/db.h**: Main interface to the DB: Start here +* **include/leveldb/db.h**: Main interface to the DB: Start here. -* **include/options.h**: Control over the behavior of an entire database, +* **include/leveldb/options.h**: Control over the behavior of an entire database, and also control over the behavior of individual reads and writes. -* **include/comparator.h**: Abstraction for user-specified comparison function. +* **include/leveldb/comparator.h**: Abstraction for user-specified comparison function. If you want just bytewise comparison of keys, you can use the default comparator, but clients can write their own comparator implementations if they -want custom ordering (e.g. to handle different character encodings, etc.) +want custom ordering (e.g. to handle different character encodings, etc.). -* **include/iterator.h**: Interface for iterating over data. You can get +* **include/leveldb/iterator.h**: Interface for iterating over data. You can get an iterator from a DB object. -* **include/write_batch.h**: Interface for atomically applying multiple +* **include/leveldb/write_batch.h**: Interface for atomically applying multiple updates to a database. -* **include/slice.h**: A simple module for maintaining a pointer and a +* **include/leveldb/slice.h**: A simple module for maintaining a pointer and a length into some other byte array. -* **include/status.h**: Status is returned from many of the public interfaces +* **include/leveldb/status.h**: Status is returned from many of the public interfaces and is used to report success and various kinds of errors. -* **include/env.h**: +* **include/leveldb/env.h**: Abstraction of the OS environment. A posix implementation of this interface is -in util/env_posix.cc +in util/env_posix.cc. -* **include/table.h, include/table_builder.h**: Lower-level modules that most -clients probably won't use directly +* **include/leveldb/table.h, include/leveldb/table_builder.h**: Lower-level modules that most +clients probably won't use directly. |