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cleanup flag docs

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without.crypto
Dan Burkert 10 years ago
parent c745961037
commit f8f13b3e86
1 changed files with 111 additions and 123 deletions
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  1. 234
      src/flags.rs

234
src/flags.rs
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@ -12,102 +12,92 @@ bitflags! {
#[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 MDB_FIXEDMAP = 0x01,
const FIXED_MAP = 0x01,
#[doc="By default, LMDB creates its environment in a directory whose"]
#[doc="pathname is given in `path`, and creates its data and lock files"]
#[doc="under that directory. With this option, `path` is used as-is for"]
#[doc="the database main data file. The database lock file is the `path`"]
#[doc="with `-lock` appended."]
const MDB_NOSUBDIR = 0x4000,
#[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 = 0x4000,
#[doc="Use a writeable memory map unless `MDB_RDONLY` is set. This is faster and uses"]
#[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 `MDB_WRITEMAP` on the same environment do not cooperate"]
#[doc="Processes with and without `WRITEMAP` on the same environment do not cooperate"]
#[doc="well."]
const MDB_WRITEMAP = 0x80000,
const WRITEMAP = 0x80000,
#[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 MDB_RDONLY = 0x20000,
#[doc="Flush system buffers to disk only once per transaction, omit the"]
#[doc="metadata flush. Defer that until the system flushes files to disk,"]
#[doc="or next non-`MDB_RDONLY` commit or #mdb_env_sync(). This optimization"]
#[doc="maintains database integrity, but a system crash may undo the last"]
#[doc="committed transaction. I.e. it preserves the ACI (atomicity,"]
#[doc="consistency, isolation) but not D (durability) database property."]
const READ_ONLY = 0x20000,
#[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 MDB_NOMETASYNC = 0x40000,
#[doc="Don't flush system buffers to disk when committing a transaction."]
#[doc="This optimization means a system crash can corrupt the database or"]
#[doc="lose the last transactions if buffers are not yet flushed to disk."]
#[doc="The risk is governed by how often the system flushes dirty buffers"]
#[doc="to disk and how often `Environment::sync` is called. However, if the"]
#[doc="filesystem preserves write order and the `MDB_WRITEMAP` flag is not"]
#[doc="used, transactions exhibit ACI (atomicity, consistency, isolation)"]
#[doc="properties and only lose D (durability). I.e. database integrity"]
#[doc="is maintained, but a system crash may undo the final transactions."]
#[doc="Note that (`MDB_NOSYNC | MDB_WRITEMAP`) leaves the system with no"]
#[doc="hint for when to write transactions to disk, unless `Environment::sync`"]
#[doc="is called. (`MDB_MAPASYNC | MDB_WRITEMAP`) may be preferable."]
const NO_META_SYNC = 0x40000,
#[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 `WRITEMAP` flag is not used,"]
#[doc="transactions exhibit ACI (atomicity, consistency, isolation) properties and only"]
#[doc="lose D (durability). I.e. database integrity"] #[doc="is maintained, but a system"]
#[doc="crash may undo the final transactions. Note that (`NO_SYNC | WRITEMAP`) leaves the"]
#[doc="system with no hint for when to write transactions to disk, unless"]
#[doc="`Environment::sync` is called. (`MAP_ASYNC | WRITEMAP`) may be preferable."]
#[doc="\n\nThis flag may be changed at any time using `Environment::set_flags`."]
const MDB_NOSYNC = 0x10000,
const NO_SYNC = 0x10000,
#[doc="When using `MDB_WRITEMAP`, use asynchronous flushes to disk."]
#[doc="As with `MDB_NOSYNC`, a system crash can then corrupt the"]
#[doc="database or lose the last transactions. Calling `Environment::sync`"]
#[doc="ensures on-disk database integrity until next commit."]
#[doc="When using `WRITEMAP`, 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 MDB_MAPASYNC = 0x100000,
#[doc="Don't use Thread-Local Storage. Tie reader locktable slots to"]
#[doc="transaction objects instead of to threads. I.e. `RoTransaction::reset` keeps"]
#[doc="the slot reseved for the transaction object. A thread may use parallel"]
#[doc="read-only transactions. A read-only transaction may span threads if"]
#[doc="the user synchronizes its use. Applications that multiplex many"]
#[doc="user threads over individual OS threads need this option. Such an"]
#[doc="application must also serialize the write transactions in an OS"]
#[doc="thread, since LMDB's write locking is unaware of the user threads."]
const MDB_NOTLS = 0x200000,
#[doc="Don't do any locking. If concurrent access is anticipated, the"]
#[doc="caller must manage all concurrency themself. For proper operation"]
#[doc="the caller must enforce single-writer semantics, and must ensure"]
#[doc="that no readers are using old transactions while a writer is"]
#[doc="active. The simplest approach is to use an exclusive lock so that"]
#[doc="no readers may be active at all when a writer begins."]
const MDB_NOLOCK = 0x400000,
#[doc="Turn off readahead. Most operating systems perform readahead on"]
#[doc="read requests by default. This option turns it off if the OS"]
#[doc="supports it. Turning it off may help random read performance"]
#[doc="when the DB is larger than RAM and system RAM is full."]
const MAP_ASYNC = 0x100000,
#[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 reseved 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 = 0x200000,
#[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 = 0x400000,
#[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 MDB_NORDAHEAD = 0x800000,
#[doc="Don't initialize malloc'd memory before writing to unused spaces"]
#[doc="in the data file. By default, memory for pages written to the data"]
#[doc="file is obtained using malloc. While these pages may be reused in"]
#[doc="subsequent transactions, freshly malloc'd pages will be initialized"]
#[doc="to zeroes before use. This avoids persisting leftover data from other"]
#[doc="code (that used the heap and subsequently freed the memory) into the"]
#[doc="data file. Note that many other system libraries may allocate"]
#[doc="and free memory from the heap for arbitrary uses. E.g., stdio may"]
#[doc="use the heap for file I/O buffers. This initialization step has a"]
#[doc="modest performance cost so some applications may want to disable"]
#[doc="it using this flag. This option can be a problem for applications"]
#[doc="which handle sensitive data like passwords, and it makes memory"]
#[doc="checkers like Valgrind noisy. This flag is not needed with `MDB_WRITEMAP`,"]
#[doc="which writes directly to the mmap instead of using malloc for pages. The"]
#[doc="initialization is also skipped if `MDB_RESERVE` is used; the"]
#[doc="caller is expected to overwrite all of the memory that was"]
const NO_READAHEAD = 0x800000,
#[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 `WRITEMAP`, 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 MDB_NOMEMINIT = 0x1000000,
const NO_MEM_INIT = 0x1000000,
}
}
@ -116,35 +106,34 @@ bitflags! {
#[deriving(Show)]
flags DatabaseFlags: c_uint {
#[doc="Keys are strings to be compared in reverse order, from the end"]
#[doc="of the strings to the beginning. By default, Keys are treated as strings and"]
#[doc="compared from beginning to end."]
const MDB_REVERSEKEY = 0x02,
#[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 MDB_DUPSORT = 0x04,
#[doc="Keys are binary integers in native byte order. Setting this option"]
#[doc="requires all keys to be the same size, typically sizeof(int)"]
#[doc="or sizeof(size_t)."]
const MDB_INTEGERKEY = 0x08,
#[doc="This flag may only be used in combination with `MDB_DUPSORT`. This option"]
#[doc="tells the library that the data items for this database are all the same"]
#[doc="size, which allows further optimizations in storage and retrieval. When"]
#[doc="all data items are the same size, the `MDB_GET_MULTIPLE` and `MDB_NEXT_MULTIPLE`"]
#[doc="cursor operations may be used to retrieve multiple items at once."]
const MDB_DUPFIXED = 0x10,
#[doc="This option specifies that duplicate data items are also integers, and"]
#[doc="should be sorted as such."]
const MDB_INTEGERDUP = 0x20,
#[doc="This option specifies that duplicate data items should be compared as"]
#[doc="strings in reverse order."]
const MDB_REVERSEDUP = 0x40,
#[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 = 0x02,
#[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 = 0x04,
#[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 = 0x08,
#[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 = 0x10,
#[doc="This option specifies that duplicate data items are also integers, and"]
#[doc="should be sorted as such."]
const INTEGER_DUP = 0x20,
#[doc="This option specifies that duplicate data items should be compared as strings"]
#[doc="in reverse order."]
const REVERSE_DUP = 0x40,
}
}
@ -155,29 +144,28 @@ bitflags! {
#[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 (`MDB_DUPSORT`)."]
const MDB_NOOVERWRITE = 0x10,
#[doc="database, even if the database supports duplicates (`DUP_SORT`)."]
const NO_OVERWRITE = 0x10,
#[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 `MDB_DUPSORT`."]
#[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 MDB_NODUPDATA = 0x20,
const NO_DUP_DATA = 0x20,
#[doc="For `Cursor::put`. Replace the item at the current cursor position."]
#[doc="The key parameter must match the current position. If using"]
#[doc="sorted duplicates (`MDB_DUPSORT`) the data item must still sort into the"]
#[doc="same position. This is intended to be used when the new data is the same"]
#[doc="size as the old. Otherwise it will simply perform a delete of the old"]
#[doc="record followed by an insert."]
const MDB_CURRENT = 0x40,
#[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 = 0x40,
#[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 MDB_APPEND = 0x20000,
const APPEND = 0x20000,
#[doc="Same as `MDB_APPEND`, but for sorted dup data."]
const MDB_APPENDDUP = 0x40000,
#[doc="Same as `APPEND`, but for sorted dup data."]
const APPEND_DUP = 0x40000,
}
}

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