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