PredicateCallbackA caller's verdict on one page of listed keys, writing one Admission per key, every one starting as Admission::Reject.pub type PredicateCallback<'handler> = dyn FnMut(&[Key], &mut [Admission]) + Send + 'handler;It runs on whichever thread runs the call, never on two at once within one call, so it owes Send and may be
FnMut. A panic inside it rejects the rest of the call's keys and resurfaces once the call is final.
Mirrors ustore_predicate_callback_t.
BlobsCursorConfigWhat admits the keys a cursor hands out; see On::cursor.pub struct BlobsCursorConfig<'config>matching | Matching<'config> | Admits only the keys it approves; every key by default. |
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BlobsSampleConfigThe keys a sample draws; see On::sample.pub struct BlobsSampleConfigwanted | usize | Keys drawn, at most. |
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Clone, Copy, Debug, From<usize>CursorA walk over the keys of one collection, which every pull resumes past the last key the pull before it handed out, so a key written behind the walk is never handed out and one written ahead of it is; see On::cursor.2pub struct Cursor<'view>A page shorter than wanted exhausts the walk for good, so every pull after it hands out nothing, even once more
keys are written. A pull that fails leaves the cursor where it was.
Mirrors ustore_blobs_cursor_t; dropping it calls ustore_blobs_cursor_free.
Debug, Drop*× 3Pulls up to wanted next keys into arena, fewer once the walk nears its end and none past it.pub fn next<'arena>(&mut self, wanted: usize, arena: &'arena mut Arena) -> Result<&'arena [Key]>Calls ustore_blobs_cursor_next.
Calls ustore_docs_cursor_next.
Calls ustore_pages_cursor_next.
next_pairsPulls up to wanted next keys with their values into arena in one call, where a key removed at the head between the listing and the read of one pull reads as an empty value.pub fn next_pairs<'arena>(
&mut self,
wanted: usize,
arena: &'arena mut Arena,
) -> Result<Page<'arena>>Calls ustore_blobs_cursor_next.
MeasurementThe bounds one measurement reported over a range of keys, each a lower and an upper estimate.pub struct Measurementmin_cardinality | usize | Lower bound on the keys in the range. |
|---|---|---|
max_cardinality | usize | Upper bound on the keys in the range. |
min_value_bytes | u64 | Lower bound on the bytes of values in the range. |
max_value_bytes | u64 | Upper bound on the bytes of values in the range. |
min_space_usage | u64 | Lower bound on the disk space the range takes. |
max_space_usage | u64 | Upper bound on the disk space the range takes. |
Clone, Copy, StructuralPartialEq, PartialEq, Eq, Debug, Default, HashPageThe keys one pull of a Cursor handed out, with their values on one tape in the arena; see Cursor::next_pairs.3keysThe keys of the page, in their order.pub fn keys(&self) -> &'arena [Key]getThe value of the key at index, or None past the end of the page.pub fn get(&self, index: usize) -> Option<&'arena [u8]>tapeEvery value of the page on the one tape the pull exported, without a copy.pub fn tape(&self) -> Tape<'arena>ScannedThe keys one scan listed, and their BM25 scores when its patterns carried weights; see On::scan.pub struct Scanned<'arena>keys | &'arena [Key] | The keys, in the order of the scan's direction. |
|---|---|---|
scores | Option<&'arena [f32]> | One score per key when the patterns carried weights. |
Clone, Copy, DebugSampleKeys drawn at random from a collection, with the values read under them through the same view into an arena.3keysThe keys drawn, in the order of their values.pub fn keys(&self) -> &[Key]valuesThe value under every key, where a key removed between the draw and the read is missing.pub fn values(&self) -> Values<'arena>SampleA random draw of keys from one collection; see On::sample.AdmissionWhether a predicate keeps a listed key or passes over it, as ustore_admission_t spells it.pub enum AdmissionReject | 0 | Pass over the key. |
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Admit | 1 | Keep the key among the listed ones. |
Clone, Copy, StructuralPartialEq, PartialEq, Eq, Debug, Default, HashCaseSensitivityWhether patterns compare bytes as they are or after Unicode case folding, as ustore_case_sensitivity_t spells it.pub enum CaseSensitivityCased | 0 | Bytes as they are. |
|---|---|---|
Uncased | 1 | Full Unicode case folding of both the patterns and the values. |
Clone, Copy, StructuralPartialEq, PartialEq, Eq, Debug, Default, Hash, Display, FromStrChangeKindWhat one committed change did to its key.pub enum ChangeKindWrite | 0 | Wrote the whole value. |
|---|---|---|
Removal | 1 | Removed the key. |
Change | 2 | Changed part of the value, as a document patch or a page edit does. |
Clone, Copy, StructuralPartialEq, PartialEq, Eq, Debug, Hash, Display, FromStrChangesThe changes one pull of a ChangesCursor handed out, oldest first, in the arena it filled.6lenHow many changes the pull handed out.pub fn len(&self) -> usizeis_emptyWhether the feed reached the newest commit.pub fn is_empty(&self) -> boolkeysThe key of every change.pub fn keys(&self) -> &'arena [Key]stampsThe stamp every change was committed at.pub fn stamps(&self) -> &'arena [CommitStamp]kindsWhat every change did.pub fn kinds(&self) -> &'arena [ChangeKind]valueThe bytes the change at index carries, empty for a removal, or None past the end or when the pull read no values.pub fn value(&self, index: usize) -> Option<&'arena [u8]>ChangesCursorA feed of the changes committed to one collection after a stamp, oldest first, which every pull resumes past the last change the pull before it handed out; see Database::changes_cursor.2pub struct ChangesCursor<'database>It pins the stamp it reads from, as a snapshot does, and holds its database open until it is dropped. A pull that fails leaves it where it was.
Debug, DropnextPulls up to wanted next changes into arena, none once the feed is at its newest commit.pub fn next<'arena>(&mut self, wanted: usize, arena: &'arena mut Arena) -> Result<Changes<'arena>>next_pairsPulls up to wanted next changes with the bytes every one carries into arena in one call.pub fn next_pairs<'arena>(
&mut self,
wanted: usize,
arena: &'arena mut Arena,
) -> Result<Changes<'arena>>ChangesCursorConfigWhere a feed of changes starts; see Database::changes_cursor.pub struct ChangesCursorConfigsince | CommitStamp | The feed hands out the changes committed after this stamp. |
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KeyRangeThe keys a scan, a cursor or a measure walks: from start, inclusive, towards end, exclusive, in the order direction names.pub struct KeyRangeA key converts into the ascending range from it, and start..end into the one between them.
start | Option<Key> | The key the walk starts from, or None for the first key in its direction. |
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end | Option<Key> | The key the walk stops before, or None to walk to the last key in its direction. |
direction | ScanDirection | Which way the walk goes from start. |
MatchingWhat a scan or a cursor narrows its keys by, every part left empty to keep every key: patterns over the values of blobs, a JSONPath or XPath filter over documents and pages, and a predicate over the keys.pub struct Matching<'matching>Mirrors the patterns, filter and predicate fields of ustore_blobs_scan_t and its kin.
patterns | &'matching [&'matching str] | The patterns every listed value matches one of, compiled once per call or once per cursor. |
|---|---|---|
pattern_kind | PatternKind | What the patterns are matched as. |
sensitivity | CaseSensitivity | Whether matching folds case. |
weights | Option<&'matching [f32]> | One weight per substring pattern, which turns on BM25 scores. |
filter | Option<&'matching str> | The JSONPath, root filter or XPath every listed document or page matches. |
predicate | Option<&'matching mut PredicateCallback<'matching>> | The caller's verdict on the keys of every page. |
predicate_cost | PredicateCost | Where the predicate is asked. |
PatternKindWhat the patterns of a Matching are matched as, as ustore_pattern_kind_t spells it.pub enum PatternKindRegex | 0 | Regular expressions, of which a value matches at least one somewhere. |
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Substrings | 1 | Literal substrings, of which a value holds at least one. |
Clone, Copy, StructuralPartialEq, PartialEq, Eq, Debug, Default, Hash, Display, FromStrPredicateCostWhere a scan asks its predicate, as ustore_predicate_cost_t spells it.pub enum PredicateCostCheap | 0 | Once per page, before patterns or filters read any value, so it narrows those reads. |
|---|---|---|
Expensive | 1 | Once per page about the keys patterns and filters kept, for handlers that pay per call. |
Clone, Copy, StructuralPartialEq, PartialEq, Eq, Debug, Default, Hash, Display, FromStrScanDirectionWhich way a scan, a cursor or a measure walks its range from the start key.pub enum ScanDirectionAscending | 0 | Up from the start key, smallest key first. |
|---|---|---|
Descending | 1 | Down from the start key, largest key first. |
Clone, Copy, StructuralPartialEq, PartialEq, Eq, Debug, Default, Hash, Display, FromStrScanModeIn what order a scan hands its keys over.pub enum ScanModeOrdered | 0 | In the order of the scan's direction. |
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Unordered | 1 | In any order, possibly removed or repeated, to speed up the read after the scan. |
Clone, Copy, StructuralPartialEq, PartialEq, Eq, Debug, Default, Hash, Display, FromStrDocsCursorA walk over the keys of one documents collection, which every pull resumes past the last key the pull before it handed out, as a crate::Cursor walks blobs, keeping the keys its Matching admits.1pub struct DocsCursor<'view>Mirrors ustore_docs_cursor_t; dropping it calls ustore_docs_cursor_free.
Debug, Dropnext_pairsPulls up to wanted next keys with their whole documents into arena in one call.pub fn next_pairs<'arena>(
&mut self,
wanted: usize,
arena: &'arena mut Arena,
) -> Result<Page<'arena>>Calls ustore_docs_cursor_next.
DocsCursorConfigWhat admits the keys a cursor hands out; see On::docs_cursor.pub struct DocsCursorConfig<'config>matching | Matching<'config> | Admits only the documents its filter and predicate approve; every document by default. |
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DocsSampleConfigThe document keys a sample draws; see On::docs_sample.pub struct DocsSampleConfigwanted | usize | Keys drawn, at most. |
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Clone, Copy, Debug, From<usize>DocsScanConfigThe document keys a scan keeps, what admits them and how it reports; see On::docs_scan.pub struct DocsScanConfig<'config>wanted | usize | Keys kept, at most. |
|---|---|---|
matching | Matching<'config> | Admits only the documents its filter and predicate approve; every document by default. |
mode | ScanMode | In what order the keys come. |
progress | Option<&'config mut ProgressCallback<'config>> | Reports the scans finished and stops wherever it says to. |
From<usize>PagesCursorA walk over the keys of one pages collection, which every pull resumes past the last key the pull before it handed out, as a crate::Cursor walks blobs, keeping the keys its Matching admits.1pub struct PagesCursor<'view>Mirrors ustore_pages_cursor_t; dropping it calls ustore_pages_cursor_free.
Debug, Dropnext_pairsPulls up to wanted next keys with their pages rendered as encoding names into arena in one call.pub fn next_pairs<'arena>(
&mut self,
wanted: usize,
arena: &'arena mut Arena,
encoding: PageEncoding,
) -> Result<Page<'arena>>Calls ustore_pages_cursor_next.
PagesCursorConfigWhat admits the page keys a cursor hands out; see On::pages_cursor.pub struct PagesCursorConfig<'config>matching | Matching<'config> | Admits only the pages its filter and predicate approve; every page by default. |
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PagesSampleConfigThe page keys a sample draws; see On::pages_sample.pub struct PagesSampleConfigwanted | usize | Page keys drawn, at most. |
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Clone, Copy, Debug, From<usize>ScanA walk over the keys of one collection; see On::scan.MeasureAn estimate of what a range of keys holds; see On::measure.DocsScanA walk over the document keys of one collection; see On::docs_scan.DocsSampleA random draw of document keys from one collection; see On::docs_sample.DocsMeasureAn estimate of what a range of documents holds; see On::docs_measure.PagesSampleA random draw of page keys from one collection; see On::pages_sample.PagesMeasureAn estimate of what a range of pages holds; see On::pages_measure.