diff options
Diffstat (limited to 'third_party/rust/lmdb-rkv/src/flags.rs')
-rw-r--r-- | third_party/rust/lmdb-rkv/src/flags.rs | 173 |
1 files changed, 173 insertions, 0 deletions
diff --git a/third_party/rust/lmdb-rkv/src/flags.rs b/third_party/rust/lmdb-rkv/src/flags.rs new file mode 100644 index 0000000000..c467405071 --- /dev/null +++ b/third_party/rust/lmdb-rkv/src/flags.rs @@ -0,0 +1,173 @@ +use libc::c_uint; + +use ffi::*; + +bitflags! { + #[doc="Environment options."] + #[derive(Default)] + pub struct EnvironmentFlags: c_uint { + + #[doc="Use a fixed address for the mmap region. This flag must be specified"] + #[doc="when creating the environment, and is stored persistently in the environment."] + #[doc="If successful, the memory map will always reside at the same virtual address"] + #[doc="and pointers used to reference data items in the database will be constant"] + #[doc="across multiple invocations. This option may not always work, depending on"] + #[doc="how the operating system has allocated memory to shared libraries and other uses."] + #[doc="The feature is highly experimental."] + const FIXED_MAP = MDB_FIXEDMAP; + + #[doc="By default, LMDB creates its environment in a directory whose pathname is given in"] + #[doc="`path`, and creates its data and lock files under that directory. With this option,"] + #[doc="`path` is used as-is for the database main data file. The database lock file is the"] + #[doc="`path` with `-lock` appended."] + const NO_SUB_DIR = MDB_NOSUBDIR; + + #[doc="Use a writeable memory map unless `READ_ONLY` is set. This is faster and uses"] + #[doc="fewer mallocs, but loses protection from application bugs like wild pointer writes"] + #[doc="and other bad updates into the database. Incompatible with nested transactions."] + #[doc="Processes with and without `WRITE_MAP` on the same environment do not cooperate"] + #[doc="well."] + const WRITE_MAP = MDB_WRITEMAP; + + #[doc="Open the environment in read-only mode. No write operations will be allowed."] + #[doc="When opening an environment, LMDB will still modify the lock file - except on"] + #[doc="read-only filesystems, where LMDB does not use locks."] + const READ_ONLY = MDB_RDONLY; + + #[doc="Flush system buffers to disk only once per transaction, omit the metadata flush."] + #[doc="Defer that until the system flushes files to disk, or next non-`READ_ONLY` commit"] + #[doc="or `Environment::sync`. This optimization maintains database integrity, but a"] + #[doc="system crash may undo the last committed transaction. I.e. it preserves the ACI"] + #[doc="(atomicity, consistency, isolation) but not D (durability) database property."] + #[doc="\n\nThis flag may be changed at any time using `Environment::set_flags`."] + const NO_META_SYNC = MDB_NOMETASYNC; + + #[doc="Don't flush system buffers to disk when committing a transaction. This optimization"] + #[doc="means a system crash can corrupt the database or lose the last transactions if"] + #[doc="buffers are not yet flushed to disk. The risk is governed by how often the system"] + #[doc="flushes dirty buffers to disk and how often `Environment::sync` is called. However,"] + #[doc="if the filesystem preserves write order and the `WRITE_MAP` flag is not used,"] + #[doc="transactions exhibit ACI (atomicity, consistency, isolation) properties and only"] + #[doc="lose D (durability). I.e. database integrity is maintained, but a system"] + #[doc="crash may undo the final transactions. Note that (`NO_SYNC | WRITE_MAP`) leaves the"] + #[doc="system with no hint for when to write transactions to disk, unless"] + #[doc="`Environment::sync` is called. (`MAP_ASYNC | WRITE_MAP`) may be preferable."] + #[doc="\n\nThis flag may be changed at any time using `Environment::set_flags`."] + const NO_SYNC = MDB_NOSYNC; + + #[doc="When using `WRITE_MAP`, use asynchronous flushes to disk. As with `NO_SYNC`, a"] + #[doc="system crash can then corrupt the database or lose the last transactions. Calling"] + #[doc="`Environment::sync` ensures on-disk database integrity until next commit."] + #[doc="\n\nThis flag may be changed at any time using `Environment::set_flags`."] + const MAP_ASYNC = MDB_MAPASYNC; + + #[doc="Don't use thread-local storage. Tie reader locktable slots to transaction objects"] + #[doc="instead of to threads. I.e. `RoTransaction::reset` keeps the slot reserved for the"] + #[doc="transaction object. A thread may use parallel read-only transactions. A read-only"] + #[doc="transaction may span threads if the user synchronizes its use. Applications that"] + #[doc="multiplex many the user synchronizes its use. Applications that multiplex many user"] + #[doc="threads over individual OS threads need this option. Such an application must also"] + #[doc="serialize the write transactions in an OS thread, since LMDB's write locking is"] + #[doc="unaware of the user threads."] + const NO_TLS = MDB_NOTLS; + + #[doc="Do not do any locking. If concurrent access is anticipated, the caller must manage"] + #[doc="all concurrency themself. For proper operation the caller must enforce"] + #[doc="single-writer semantics, and must ensure that no readers are using old"] + #[doc="transactions while a writer is active. The simplest approach is to use an exclusive"] + #[doc="lock so that no readers may be active at all when a writer begins."] + const NO_LOCK = MDB_NOLOCK; + + #[doc="Turn off readahead. Most operating systems perform readahead on read requests by"] + #[doc="default. This option turns it off if the OS supports it. Turning it off may help"] + #[doc="random read performance when the DB is larger than RAM and system RAM is full."] + #[doc="The option is not implemented on Windows."] + const NO_READAHEAD = MDB_NORDAHEAD; + + #[doc="Do not initialize malloc'd memory before writing to unused spaces in the data file."] + #[doc="By default, memory for pages written to the data file is obtained using malloc."] + #[doc="While these pages may be reused in subsequent transactions, freshly malloc'd pages"] + #[doc="will be initialized to zeroes before use. This avoids persisting leftover data from"] + #[doc="other code (that used the heap and subsequently freed the memory) into the data"] + #[doc="file. Note that many other system libraries may allocate and free memory from the"] + #[doc="heap for arbitrary uses. E.g., stdio may use the heap for file I/O buffers. This"] + #[doc="initialization step has a modest performance cost so some applications may want to"] + #[doc="disable it using this flag. This option can be a problem for applications which"] + #[doc="handle sensitive data like passwords, and it makes memory checkers like Valgrind"] + #[doc="noisy. This flag is not needed with `WRITE_MAP`, which writes directly to the mmap"] + #[doc="instead of using malloc for pages. The initialization is also skipped if writing"] + #[doc="with reserve; the caller is expected to overwrite all of the memory that was"] + #[doc="reserved in that case."] + #[doc="\n\nThis flag may be changed at any time using `Environment::set_flags`."] + const NO_MEM_INIT = MDB_NOMEMINIT; + } +} + +bitflags! { + #[doc="Database options."] + #[derive(Default)] + pub struct DatabaseFlags: c_uint { + + #[doc="Keys are strings to be compared in reverse order, from the end of the strings"] + #[doc="to the beginning. By default, Keys are treated as strings and compared from"] + #[doc="beginning to end."] + const REVERSE_KEY = MDB_REVERSEKEY; + + #[doc="Duplicate keys may be used in the database. (Or, from another perspective,"] + #[doc="keys may have multiple data items, stored in sorted order.) By default"] + #[doc="keys must be unique and may have only a single data item."] + const DUP_SORT = MDB_DUPSORT; + + #[doc="Keys are binary integers in native byte order. Setting this option requires all"] + #[doc="keys to be the same size, typically 32 or 64 bits."] + const INTEGER_KEY = MDB_INTEGERKEY; + + #[doc="This flag may only be used in combination with `DUP_SORT`. This option tells"] + #[doc="the library that the data items for this database are all the same size, which"] + #[doc="allows further optimizations in storage and retrieval. When all data items are"] + #[doc="the same size, the `GET_MULTIPLE` and `NEXT_MULTIPLE` cursor operations may be"] + #[doc="used to retrieve multiple items at once."] + const DUP_FIXED = MDB_DUPFIXED; + + #[doc="This option specifies that duplicate data items are also integers, and"] + #[doc="should be sorted as such."] + const INTEGER_DUP = MDB_INTEGERDUP; + + #[doc="This option specifies that duplicate data items should be compared as strings"] + #[doc="in reverse order."] + const REVERSE_DUP = MDB_REVERSEDUP; + } +} + +bitflags! { + #[doc="Write options."] + #[derive(Default)] + pub struct WriteFlags: c_uint { + + #[doc="Insert the new item only if the key does not already appear in the database."] + #[doc="The function will return `LmdbError::KeyExist` if the key already appears in the"] + #[doc="database, even if the database supports duplicates (`DUP_SORT`)."] + const NO_OVERWRITE = MDB_NOOVERWRITE; + + #[doc="Insert the new item only if it does not already appear in the database."] + #[doc="This flag may only be specified if the database was opened with `DUP_SORT`."] + #[doc="The function will return `LmdbError::KeyExist` if the item already appears in the"] + #[doc="database."] + const NO_DUP_DATA = MDB_NODUPDATA; + + #[doc="For `Cursor::put`. Replace the item at the current cursor position. The key"] + #[doc="parameter must match the current position. If using sorted duplicates (`DUP_SORT`)"] + #[doc="the data item must still sort into the same position. This is intended to be used"] + #[doc="when the new data is the same size as the old. Otherwise it will simply perform a"] + #[doc="delete of the old record followed by an insert."] + const CURRENT = MDB_CURRENT; + + #[doc="Append the given item to the end of the database. No key comparisons are performed."] + #[doc="This option allows fast bulk loading when keys are already known to be in the"] + #[doc="correct order. Loading unsorted keys with this flag will cause data corruption."] + const APPEND = MDB_APPEND; + + #[doc="Same as `APPEND`, but for sorted dup data."] + const APPEND_DUP = MDB_APPENDDUP; + } +} |