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<!DOCTYPE html><html lang="en"><head><meta charset="utf-8"><meta name="viewport" content="width=device-width, initial-scale=1.0"><meta name="generator" content="rustdoc"><meta name="description" content="Source of the Rust file `common/rusty_leveldb_sgx/src/db_iter.rs`."><meta name="keywords" content="rust, rustlang, rust-lang"><title>db_iter.rs - source</title><link rel="preload" as="font" type="font/woff2" crossorigin href="../../SourceSerif4-Regular.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../FiraSans-Regular.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../FiraSans-Medium.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../SourceCodePro-Regular.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../SourceSerif4-Bold.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../SourceCodePro-Semibold.ttf.woff2"><link rel="stylesheet" href="../../normalize.css"><link rel="stylesheet" href="../../rustdoc.css" id="mainThemeStyle"><link rel="stylesheet" href="../../ayu.css" disabled><link rel="stylesheet" href="../../dark.css" disabled><link rel="stylesheet" href="../../light.css" id="themeStyle"><script id="default-settings" ></script><script src="../../storage.js"></script><script defer src="../../source-script.js"></script><script defer src="../../source-files.js"></script><script defer src="../../main.js"></script><noscript><link rel="stylesheet" href="../../noscript.css"></noscript><link rel="alternate icon" type="image/png" href="../../favicon-16x16.png"><link rel="alternate icon" type="image/png" href="../../favicon-32x32.png"><link rel="icon" type="image/svg+xml" href="../../favicon.svg"></head><body class="rustdoc source"><!--[if lte IE 11]><div class="warning">This old browser is unsupported and will most likely display funky things.</div><![endif]--><nav class="sidebar"><a class="sidebar-logo" href="../../rusty_leveldb/index.html"><div class="logo-container"><img class="rust-logo" src="../../rust-logo.svg" alt="logo"></div></a></nav><main><div class="width-limiter"><nav class="sub"><a class="sub-logo-container" href="../../rusty_leveldb/index.html"><img class="rust-logo" src="../../rust-logo.svg" alt="logo"></a><form class="search-form"><div class="search-container"><span></span><input class="search-input" name="search" autocomplete="off" spellcheck="false" placeholder="Click or press ‘S’ to search, ‘?’ for more options…" type="search"><div id="help-button" title="help" tabindex="-1"><a href="../../help.html">?</a></div><div id="settings-menu" tabindex="-1"><a href="../../settings.html" title="settings"><img width="22" height="22" alt="Change settings" src="../../wheel.svg"></a></div></div></form></nav><section id="main-content" class="content"><div class="example-wrap"><pre class="src-line-numbers"><span id="1">1</span>
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</pre><pre class="rust"><code><span class="kw">use </span><span class="kw">crate</span>::cmp::Cmp;
<span class="kw">use </span><span class="kw">crate</span>::key_types::{parse_internal_key, truncate_to_userkey, LookupKey, ValueType};
<span class="kw">use </span><span class="kw">crate</span>::merging_iter::MergingIter;
<span class="kw">use </span><span class="kw">crate</span>::snapshot::Snapshot;
<span class="kw">use </span><span class="kw">crate</span>::types::{Direction, LdbIterator, Shared};
<span class="kw">use </span><span class="kw">crate</span>::version_set::VersionSet;
<span class="kw">use </span>std::cmp::Ordering;
<span class="kw">use </span>std::mem;
<span class="kw">use </span>std::rc::Rc;
<span class="kw">use </span>rand;
<span class="kw">const </span>READ_BYTES_PERIOD: isize = <span class="number">1048576</span>;
<span class="doccomment">/// DBIterator is an iterator over the contents of a database.
</span><span class="kw">pub struct </span>DBIterator {
<span class="comment">// A user comparator.
</span>cmp: Rc&lt;Box&lt;<span class="kw">dyn </span>Cmp&gt;&gt;,
vset: Shared&lt;VersionSet&gt;,
iter: MergingIter,
<span class="comment">// By holding onto a snapshot, we make sure that the iterator iterates over the state at the
// point of its creation.
</span>ss: Snapshot,
dir: Direction,
byte_count: isize,
valid: bool,
<span class="comment">// temporarily stored user key.
</span>savedkey: Vec&lt;u8&gt;,
<span class="comment">// buffer for reading internal keys
</span>keybuf: Vec&lt;u8&gt;,
savedval: Vec&lt;u8&gt;,
valbuf: Vec&lt;u8&gt;,
}
<span class="kw">impl </span>DBIterator {
<span class="kw">pub fn </span>new(
cmp: Rc&lt;Box&lt;<span class="kw">dyn </span>Cmp&gt;&gt;,
vset: Shared&lt;VersionSet&gt;,
iter: MergingIter,
ss: Snapshot,
) -&gt; DBIterator {
DBIterator {
cmp,
vset,
iter,
ss,
dir: Direction::Forward,
byte_count: random_period(),
valid: <span class="bool-val">false</span>,
savedkey: <span class="macro">vec!</span>[],
keybuf: <span class="macro">vec!</span>[],
savedval: <span class="macro">vec!</span>[],
valbuf: <span class="macro">vec!</span>[],
}
}
<span class="doccomment">/// record_read_sample records a read sample using the current contents of self.keybuf, which
/// should be an InternalKey.
</span><span class="kw">fn </span>record_read_sample(<span class="kw-2">&amp;mut </span><span class="self">self</span>, len: usize) {
<span class="self">self</span>.byte_count -= len <span class="kw">as </span>isize;
<span class="kw">if </span><span class="self">self</span>.byte_count &lt; <span class="number">0 </span>{
<span class="kw">let </span>v = <span class="self">self</span>.vset.borrow().current();
v.borrow_mut().record_read_sample(<span class="kw-2">&amp;</span><span class="self">self</span>.keybuf);
<span class="kw">while </span><span class="self">self</span>.byte_count &lt; <span class="number">0 </span>{
<span class="self">self</span>.byte_count += random_period();
}
}
}
<span class="doccomment">/// find_next_user_entry skips to the next user entry after the one saved in self.savedkey.
</span><span class="kw">fn </span>find_next_user_entry(<span class="kw-2">&amp;mut </span><span class="self">self</span>, <span class="kw-2">mut </span>skipping: bool) -&gt; bool {
<span class="macro">assert!</span>(<span class="self">self</span>.iter.valid());
<span class="macro">assert!</span>(<span class="self">self</span>.dir == Direction::Forward);
<span class="kw">while </span><span class="self">self</span>.iter.valid() {
<span class="self">self</span>.iter.current(<span class="kw-2">&amp;mut </span><span class="self">self</span>.keybuf, <span class="kw-2">&amp;mut </span><span class="self">self</span>.savedval);
<span class="kw">let </span>len = <span class="self">self</span>.keybuf.len() + <span class="self">self</span>.savedval.len();
<span class="self">self</span>.record_read_sample(len);
<span class="kw">let </span>(typ, seq, ukey) = parse_internal_key(<span class="kw-2">&amp;</span><span class="self">self</span>.keybuf);
<span class="comment">// Skip keys with a sequence number after our snapshot.
</span><span class="kw">if </span>seq &lt;= <span class="self">self</span>.ss.sequence() {
<span class="kw">if </span>typ == ValueType::TypeDeletion {
<span class="comment">// Mark current (deleted) key to be skipped.
</span><span class="self">self</span>.savedkey.clear();
<span class="self">self</span>.savedkey.extend_from_slice(ukey);
skipping = <span class="bool-val">true</span>;
} <span class="kw">else if </span>typ == ValueType::TypeValue {
<span class="kw">if </span>skipping &amp;&amp; <span class="self">self</span>.cmp.cmp(ukey, <span class="kw-2">&amp;</span><span class="self">self</span>.savedkey) &lt;= Ordering::Equal {
<span class="comment">// Entry hidden, because it&#39;s smaller than the key to be skipped.
</span>} <span class="kw">else </span>{
<span class="self">self</span>.valid = <span class="bool-val">true</span>;
<span class="self">self</span>.savedkey.clear();
<span class="kw">return </span><span class="bool-val">true</span>;
}
}
}
<span class="self">self</span>.iter.advance();
}
<span class="self">self</span>.savedkey.clear();
<span class="self">self</span>.valid = <span class="bool-val">false</span>;
<span class="bool-val">false
</span>}
<span class="doccomment">/// find_prev_user_entry, on a backwards-moving iterator, stores the newest non-deleted version
/// of the entry with the key == self.savedkey that is in the current snapshot, into
/// savedkey/savedval.
</span><span class="kw">fn </span>find_prev_user_entry(<span class="kw-2">&amp;mut </span><span class="self">self</span>) -&gt; bool {
<span class="macro">assert!</span>(<span class="self">self</span>.dir == Direction::Reverse);
<span class="kw">let </span><span class="kw-2">mut </span>value_type = ValueType::TypeDeletion;
<span class="comment">// The iterator should be already set to the previous entry if this is a direction change
// (i.e. first prev() call after advance()). savedkey is set to the key of that entry.
//
// We read the current entry, ignore it for comparison (because the initial value_type is
// Deletion), assign it to savedkey and savedval and go back another step (at the end of
// the loop).
//
// We repeat this until we hit the first entry with a different user key (possibly going
// through newer versions of the same key, because the newest entry is first in order),
// then break. The key and value of the latest entry for the desired key have been stored
// in the previous iteration to savedkey and savedval.
</span><span class="kw">while </span><span class="self">self</span>.iter.valid() {
<span class="self">self</span>.iter.current(<span class="kw-2">&amp;mut </span><span class="self">self</span>.keybuf, <span class="kw-2">&amp;mut </span><span class="self">self</span>.valbuf);
<span class="kw">let </span>len = <span class="self">self</span>.keybuf.len() + <span class="self">self</span>.valbuf.len();
<span class="self">self</span>.record_read_sample(len);
<span class="kw">let </span>(typ, seq, ukey) = parse_internal_key(<span class="kw-2">&amp;</span><span class="self">self</span>.keybuf);
<span class="kw">if </span>seq &gt; <span class="number">0 </span>&amp;&amp; seq &lt;= <span class="self">self</span>.ss.sequence() {
<span class="kw">if </span>value_type != ValueType::TypeDeletion
&amp;&amp; <span class="self">self</span>.cmp.cmp(ukey, <span class="kw-2">&amp;</span><span class="self">self</span>.savedkey) == Ordering::Less
{
<span class="comment">// We found a non-deleted entry for a previous key (in the previous iteration)
</span><span class="kw">break</span>;
}
value_type = typ;
<span class="kw">if </span>value_type == ValueType::TypeDeletion {
<span class="self">self</span>.savedkey.clear();
<span class="self">self</span>.savedval.clear();
} <span class="kw">else </span>{
<span class="self">self</span>.savedkey.clear();
<span class="self">self</span>.savedkey.extend_from_slice(ukey);
mem::swap(<span class="kw-2">&amp;mut </span><span class="self">self</span>.savedval, <span class="kw-2">&amp;mut </span><span class="self">self</span>.valbuf);
}
}
<span class="self">self</span>.iter.prev();
}
<span class="kw">if </span>value_type == ValueType::TypeDeletion {
<span class="self">self</span>.valid = <span class="bool-val">false</span>;
<span class="self">self</span>.savedkey.clear();
<span class="self">self</span>.savedval.clear();
<span class="self">self</span>.dir = Direction::Forward;
} <span class="kw">else </span>{
<span class="self">self</span>.valid = <span class="bool-val">true</span>;
}
<span class="bool-val">true
</span>}
}
<span class="kw">impl </span>LdbIterator <span class="kw">for </span>DBIterator {
<span class="kw">fn </span>advance(<span class="kw-2">&amp;mut </span><span class="self">self</span>) -&gt; bool {
<span class="kw">if </span>!<span class="self">self</span>.valid() {
<span class="self">self</span>.seek_to_first();
<span class="kw">return </span><span class="self">self</span>.valid();
}
<span class="kw">if </span><span class="self">self</span>.dir == Direction::Reverse {
<span class="self">self</span>.dir = Direction::Forward;
<span class="kw">if </span>!<span class="self">self</span>.iter.valid() {
<span class="self">self</span>.iter.seek_to_first();
} <span class="kw">else </span>{
<span class="self">self</span>.iter.advance();
}
<span class="kw">if </span>!<span class="self">self</span>.iter.valid() {
<span class="self">self</span>.valid = <span class="bool-val">false</span>;
<span class="self">self</span>.savedkey.clear();
<span class="kw">return </span><span class="bool-val">false</span>;
}
} <span class="kw">else </span>{
<span class="comment">// Save current user key.
</span><span class="macro">assert!</span>(<span class="self">self</span>.iter.current(<span class="kw-2">&amp;mut </span><span class="self">self</span>.savedkey, <span class="kw-2">&amp;mut </span><span class="self">self</span>.savedval));
truncate_to_userkey(<span class="kw-2">&amp;mut </span><span class="self">self</span>.savedkey);
}
<span class="self">self</span>.find_next_user_entry(
<span class="comment">// skipping=
</span><span class="bool-val">true</span>,
)
}
<span class="kw">fn </span>current(<span class="kw-2">&amp;</span><span class="self">self</span>, key: <span class="kw-2">&amp;mut </span>Vec&lt;u8&gt;, val: <span class="kw-2">&amp;mut </span>Vec&lt;u8&gt;) -&gt; bool {
<span class="kw">if </span>!<span class="self">self</span>.valid() {
<span class="kw">return </span><span class="bool-val">false</span>;
}
<span class="comment">// If direction is forward, savedkey and savedval are not used.
</span><span class="kw">if </span><span class="self">self</span>.dir == Direction::Forward {
<span class="self">self</span>.iter.current(key, val);
truncate_to_userkey(key);
<span class="bool-val">true
</span>} <span class="kw">else </span>{
key.clear();
key.extend_from_slice(<span class="kw-2">&amp;</span><span class="self">self</span>.savedkey);
val.clear();
val.extend_from_slice(<span class="kw-2">&amp;</span><span class="self">self</span>.savedval);
<span class="bool-val">true
</span>}
}
<span class="kw">fn </span>prev(<span class="kw-2">&amp;mut </span><span class="self">self</span>) -&gt; bool {
<span class="kw">if </span>!<span class="self">self</span>.valid() {
<span class="kw">return </span><span class="bool-val">false</span>;
}
<span class="kw">if </span><span class="self">self</span>.dir == Direction::Forward {
<span class="comment">// scan backwards until we hit a different key; then use the normal scanning procedure:
// find_prev_user_entry() wants savedkey to be the key of the entry that is supposed to
// be left in savedkey/savedval, which is why we have to go to the previous entry before
// calling it.
</span><span class="self">self</span>.iter.current(<span class="kw-2">&amp;mut </span><span class="self">self</span>.savedkey, <span class="kw-2">&amp;mut </span><span class="self">self</span>.savedval);
truncate_to_userkey(<span class="kw-2">&amp;mut </span><span class="self">self</span>.savedkey);
<span class="kw">loop </span>{
<span class="self">self</span>.iter.prev();
<span class="kw">if </span>!<span class="self">self</span>.iter.valid() {
<span class="self">self</span>.valid = <span class="bool-val">false</span>;
<span class="self">self</span>.savedkey.clear();
<span class="self">self</span>.savedval.clear();
<span class="kw">return </span><span class="bool-val">false</span>;
}
<span class="comment">// Scan until we hit the next-smaller key.
</span><span class="self">self</span>.iter.current(<span class="kw-2">&amp;mut </span><span class="self">self</span>.keybuf, <span class="kw-2">&amp;mut </span><span class="self">self</span>.savedval);
truncate_to_userkey(<span class="kw-2">&amp;mut </span><span class="self">self</span>.keybuf);
<span class="kw">if </span><span class="self">self</span>.cmp.cmp(<span class="kw-2">&amp;</span><span class="self">self</span>.keybuf, <span class="kw-2">&amp;</span><span class="self">self</span>.savedkey) == Ordering::Less {
<span class="kw">break</span>;
}
}
<span class="self">self</span>.dir = Direction::Reverse;
}
<span class="self">self</span>.find_prev_user_entry()
}
<span class="kw">fn </span>valid(<span class="kw-2">&amp;</span><span class="self">self</span>) -&gt; bool {
<span class="self">self</span>.valid
}
<span class="kw">fn </span>seek(<span class="kw-2">&amp;mut </span><span class="self">self</span>, to: <span class="kw-2">&amp;</span>[u8]) {
<span class="self">self</span>.dir = Direction::Forward;
<span class="self">self</span>.savedkey.clear();
<span class="self">self</span>.savedval.clear();
<span class="self">self</span>.savedkey
.extend_from_slice(LookupKey::new(to, <span class="self">self</span>.ss.sequence()).internal_key());
<span class="self">self</span>.iter.seek(<span class="kw-2">&amp;</span><span class="self">self</span>.savedkey);
<span class="kw">if </span><span class="self">self</span>.iter.valid() {
<span class="self">self</span>.find_next_user_entry(
<span class="comment">// skipping=
</span><span class="bool-val">false</span>,
);
} <span class="kw">else </span>{
<span class="self">self</span>.valid = <span class="bool-val">false</span>;
}
}
<span class="kw">fn </span>seek_to_first(<span class="kw-2">&amp;mut </span><span class="self">self</span>) {
<span class="self">self</span>.dir = Direction::Forward;
<span class="self">self</span>.savedval.clear();
<span class="self">self</span>.iter.seek_to_first();
<span class="kw">if </span><span class="self">self</span>.iter.valid() {
<span class="self">self</span>.find_next_user_entry(
<span class="comment">// skipping=
</span><span class="bool-val">false</span>,
);
} <span class="kw">else </span>{
<span class="self">self</span>.valid = <span class="bool-val">false</span>;
}
}
<span class="kw">fn </span>reset(<span class="kw-2">&amp;mut </span><span class="self">self</span>) {
<span class="self">self</span>.iter.reset();
<span class="self">self</span>.valid = <span class="bool-val">false</span>;
<span class="self">self</span>.savedkey.clear();
<span class="self">self</span>.savedval.clear();
<span class="self">self</span>.keybuf.clear();
}
}
<span class="kw">fn </span>random_period() -&gt; isize {
rand::random::&lt;isize&gt;() % (<span class="number">2 </span>* READ_BYTES_PERIOD)
}
<span class="attribute">#[cfg(feature = <span class="string">&quot;enclave_unit_test&quot;</span>)]
</span><span class="kw">pub mod </span>tests {
<span class="kw">use super</span>::<span class="kw-2">*</span>;
<span class="kw">use </span><span class="kw">crate</span>::db_impl::testutil::<span class="kw-2">*</span>;
<span class="kw">use </span><span class="kw">crate</span>::db_impl::DB;
<span class="kw">use </span><span class="kw">crate</span>::options;
<span class="kw">use </span><span class="kw">crate</span>::test_util::LdbIteratorIter;
<span class="kw">use </span><span class="kw">crate</span>::types::{current_key_val, Direction};
<span class="kw">use </span>std::collections::HashMap;
<span class="kw">use </span>std::collections::HashSet;
<span class="kw">use </span>std::iter::FromIterator;
<span class="kw">use </span>teaclave_test_utils::<span class="kw-2">*</span>;
<span class="kw">pub fn </span>run_tests() -&gt; bool {
<span class="macro">run_tests!</span>(
db_iter_basic_test,
db_iter_reset,
db_iter_test_fwd_backwd,
db_iter_test_seek,
db_iter_deleted_entry_not_returned,
db_iter_deleted_entry_not_returned_memtable,
db_iter_repeated_open_close,
db_iter_allow_empty_key,
)
}
<span class="kw">fn </span>db_iter_basic_test() {
<span class="kw">let </span><span class="kw-2">mut </span>db = build_db().<span class="number">0</span>;
<span class="kw">let </span><span class="kw-2">mut </span>iter = db.new_iter().unwrap();
<span class="comment">// keys and values come from make_version(); they are each the latest entry.
</span><span class="kw">let </span>keys: <span class="kw-2">&amp;</span>[<span class="kw-2">&amp;</span>[u8]] = <span class="kw-2">&amp;</span>[
<span class="string">b&quot;aaa&quot;</span>, <span class="string">b&quot;aab&quot;</span>, <span class="string">b&quot;aax&quot;</span>, <span class="string">b&quot;aba&quot;</span>, <span class="string">b&quot;bab&quot;</span>, <span class="string">b&quot;bba&quot;</span>, <span class="string">b&quot;cab&quot;</span>, <span class="string">b&quot;cba&quot;</span>,
];
<span class="kw">let </span>vals: <span class="kw-2">&amp;</span>[<span class="kw-2">&amp;</span>[u8]] = <span class="kw-2">&amp;</span>[
<span class="string">b&quot;val1&quot;</span>, <span class="string">b&quot;val2&quot;</span>, <span class="string">b&quot;val2&quot;</span>, <span class="string">b&quot;val3&quot;</span>, <span class="string">b&quot;val4&quot;</span>, <span class="string">b&quot;val5&quot;</span>, <span class="string">b&quot;val2&quot;</span>, <span class="string">b&quot;val3&quot;</span>,
];
<span class="kw">for </span>(k, v) <span class="kw">in </span>keys.iter().zip(vals.iter()) {
<span class="macro">assert!</span>(iter.advance());
<span class="macro">assert_eq!</span>((k.to_vec(), v.to_vec()), current_key_val(<span class="kw-2">&amp;</span>iter).unwrap());
}
}
<span class="kw">fn </span>db_iter_reset() {
<span class="kw">let </span><span class="kw-2">mut </span>db = build_db().<span class="number">0</span>;
<span class="kw">let </span><span class="kw-2">mut </span>iter = db.new_iter().unwrap();
<span class="macro">assert!</span>(iter.advance());
<span class="macro">assert!</span>(iter.valid());
iter.reset();
<span class="macro">assert!</span>(!iter.valid());
<span class="macro">assert!</span>(iter.advance());
<span class="macro">assert!</span>(iter.valid());
}
<span class="kw">fn </span>db_iter_test_fwd_backwd() {
<span class="kw">let </span><span class="kw-2">mut </span>db = build_db().<span class="number">0</span>;
<span class="kw">let </span><span class="kw-2">mut </span>iter = db.new_iter().unwrap();
<span class="comment">// keys and values come from make_version(); they are each the latest entry.
</span><span class="kw">let </span>keys: <span class="kw-2">&amp;</span>[<span class="kw-2">&amp;</span>[u8]] = <span class="kw-2">&amp;</span>[
<span class="string">b&quot;aaa&quot;</span>, <span class="string">b&quot;aab&quot;</span>, <span class="string">b&quot;aax&quot;</span>, <span class="string">b&quot;aba&quot;</span>, <span class="string">b&quot;bab&quot;</span>, <span class="string">b&quot;bba&quot;</span>, <span class="string">b&quot;cab&quot;</span>, <span class="string">b&quot;cba&quot;</span>,
];
<span class="kw">let </span>vals: <span class="kw-2">&amp;</span>[<span class="kw-2">&amp;</span>[u8]] = <span class="kw-2">&amp;</span>[
<span class="string">b&quot;val1&quot;</span>, <span class="string">b&quot;val2&quot;</span>, <span class="string">b&quot;val2&quot;</span>, <span class="string">b&quot;val3&quot;</span>, <span class="string">b&quot;val4&quot;</span>, <span class="string">b&quot;val5&quot;</span>, <span class="string">b&quot;val2&quot;</span>, <span class="string">b&quot;val3&quot;</span>,
];
<span class="comment">// This specifies the direction that the iterator should move to. Based on this, an index
// into keys/vals is incremented/decremented so that we get a nice test checking iterator
// move correctness.
</span><span class="kw">let </span>dirs: <span class="kw-2">&amp;</span>[Direction] = <span class="kw-2">&amp;</span>[
Direction::Forward,
Direction::Forward,
Direction::Forward,
Direction::Reverse,
Direction::Reverse,
Direction::Reverse,
Direction::Forward,
Direction::Forward,
Direction::Reverse,
Direction::Forward,
Direction::Forward,
Direction::Forward,
Direction::Forward,
];
<span class="kw">let </span><span class="kw-2">mut </span>i = <span class="number">0</span>;
iter.advance();
<span class="kw">for </span>d <span class="kw">in </span>dirs {
<span class="macro">assert_eq!</span>(
(keys[i].to_vec(), vals[i].to_vec()),
current_key_val(<span class="kw-2">&amp;</span>iter).unwrap()
);
<span class="kw">match </span><span class="kw-2">*</span>d {
Direction::Forward =&gt; {
<span class="macro">assert!</span>(iter.advance());
i += <span class="number">1</span>;
}
Direction::Reverse =&gt; {
<span class="macro">assert!</span>(iter.prev());
i -= <span class="number">1</span>;
}
}
}
}
<span class="kw">fn </span>db_iter_test_seek() {
<span class="kw">let </span><span class="kw-2">mut </span>db = build_db().<span class="number">0</span>;
<span class="kw">let </span><span class="kw-2">mut </span>iter = db.new_iter().unwrap();
<span class="comment">// gca is the deleted entry.
</span><span class="kw">let </span>keys: <span class="kw-2">&amp;</span>[<span class="kw-2">&amp;</span>[u8]] = <span class="kw-2">&amp;</span>[<span class="string">b&quot;aab&quot;</span>, <span class="string">b&quot;aaa&quot;</span>, <span class="string">b&quot;cab&quot;</span>, <span class="string">b&quot;eaa&quot;</span>, <span class="string">b&quot;aaa&quot;</span>, <span class="string">b&quot;iba&quot;</span>, <span class="string">b&quot;fba&quot;</span>];
<span class="kw">let </span>vals: <span class="kw-2">&amp;</span>[<span class="kw-2">&amp;</span>[u8]] = <span class="kw-2">&amp;</span>[
<span class="string">b&quot;val2&quot;</span>, <span class="string">b&quot;val1&quot;</span>, <span class="string">b&quot;val2&quot;</span>, <span class="string">b&quot;val1&quot;</span>, <span class="string">b&quot;val1&quot;</span>, <span class="string">b&quot;val2&quot;</span>, <span class="string">b&quot;val3&quot;</span>,
];
<span class="kw">for </span>(k, v) <span class="kw">in </span>keys.iter().zip(vals.iter()) {
<span class="macro">println!</span>(<span class="string">&quot;{:?}&quot;</span>, String::from_utf8(k.to_vec()).unwrap());
iter.seek(k);
<span class="macro">assert_eq!</span>((k.to_vec(), v.to_vec()), current_key_val(<span class="kw-2">&amp;</span>iter).unwrap());
}
<span class="comment">// seek past last.
</span>iter.seek(<span class="string">b&quot;xxx&quot;</span>);
<span class="macro">assert!</span>(!iter.valid());
iter.seek(<span class="string">b&quot;aab&quot;</span>);
<span class="macro">assert!</span>(iter.valid());
<span class="comment">// Seek skips over deleted entry.
</span>iter.seek(<span class="string">b&quot;gca&quot;</span>);
<span class="macro">assert!</span>(iter.valid());
<span class="macro">assert_eq!</span>(
(<span class="string">b&quot;gda&quot;</span>.to_vec(), <span class="string">b&quot;val5&quot;</span>.to_vec()),
current_key_val(<span class="kw-2">&amp;</span>iter).unwrap()
);
}
<span class="kw">fn </span>db_iter_deleted_entry_not_returned() {
<span class="kw">let </span><span class="kw-2">mut </span>db = build_db().<span class="number">0</span>;
<span class="kw">let </span><span class="kw-2">mut </span>iter = db.new_iter().unwrap();
<span class="kw">let </span>must_not_appear = <span class="string">b&quot;gca&quot;</span>;
<span class="kw">for </span>(k, <span class="kw">_</span>) <span class="kw">in </span>LdbIteratorIter::wrap(<span class="kw-2">&amp;mut </span>iter) {
<span class="macro">assert!</span>(k.as_slice() != must_not_appear);
}
}
<span class="kw">fn </span>db_iter_deleted_entry_not_returned_memtable() {
<span class="kw">let </span><span class="kw-2">mut </span>db = build_db().<span class="number">0</span>;
db.put(<span class="string">b&quot;xyz&quot;</span>, <span class="string">b&quot;123&quot;</span>).unwrap();
db.delete(<span class="string">b&quot;xyz&quot;</span>).unwrap();
<span class="kw">let </span><span class="kw-2">mut </span>iter = db.new_iter().unwrap();
<span class="kw">let </span>must_not_appear = <span class="string">b&quot;xyz&quot;</span>;
<span class="kw">for </span>(k, <span class="kw">_</span>) <span class="kw">in </span>LdbIteratorIter::wrap(<span class="kw-2">&amp;mut </span>iter) {
<span class="macro">assert!</span>(k.as_slice() != must_not_appear);
}
}
<span class="kw">fn </span>db_iter_repeated_open_close() {
<span class="kw">let </span>opt;
{
<span class="kw">let </span>(<span class="kw-2">mut </span>db, opt_) = build_db();
opt = opt_;
db.put(<span class="string">b&quot;xx1&quot;</span>, <span class="string">b&quot;111&quot;</span>).unwrap();
db.put(<span class="string">b&quot;xx2&quot;</span>, <span class="string">b&quot;112&quot;</span>).unwrap();
db.put(<span class="string">b&quot;xx3&quot;</span>, <span class="string">b&quot;113&quot;</span>).unwrap();
db.put(<span class="string">b&quot;xx4&quot;</span>, <span class="string">b&quot;114&quot;</span>).unwrap();
db.delete(<span class="string">b&quot;xx2&quot;</span>).unwrap();
}
{
<span class="kw">let </span><span class="kw-2">mut </span>db = DB::open(<span class="string">&quot;db&quot;</span>, opt.clone()).unwrap();
db.put(<span class="string">b&quot;xx4&quot;</span>, <span class="string">b&quot;222&quot;</span>).unwrap();
}
{
<span class="kw">let </span><span class="kw-2">mut </span>db = DB::open(<span class="string">&quot;db&quot;</span>, opt).unwrap();
<span class="kw">let </span>ss = db.get_snapshot();
<span class="comment">// xx5 should not be visible.
</span>db.put(<span class="string">b&quot;xx5&quot;</span>, <span class="string">b&quot;223&quot;</span>).unwrap();
<span class="kw">let </span>expected: HashMap&lt;Vec&lt;u8&gt;, Vec&lt;u8&gt;&gt; = HashMap::from_iter(
<span class="macro">vec!</span>[
(<span class="string">b&quot;xx1&quot;</span>.to_vec(), <span class="string">b&quot;111&quot;</span>.to_vec()),
(<span class="string">b&quot;xx4&quot;</span>.to_vec(), <span class="string">b&quot;222&quot;</span>.to_vec()),
(<span class="string">b&quot;aaa&quot;</span>.to_vec(), <span class="string">b&quot;val1&quot;</span>.to_vec()),
(<span class="string">b&quot;cab&quot;</span>.to_vec(), <span class="string">b&quot;val2&quot;</span>.to_vec()),
]
.into_iter(),
);
<span class="kw">let </span>non_existing: HashSet&lt;Vec&lt;u8&gt;&gt; = HashSet::from_iter(
<span class="macro">vec!</span>[<span class="string">b&quot;gca&quot;</span>.to_vec(), <span class="string">b&quot;xx2&quot;</span>.to_vec(), <span class="string">b&quot;xx5&quot;</span>.to_vec()].into_iter(),
);
<span class="kw">let </span><span class="kw-2">mut </span>iter = db.new_iter_at(ss.clone()).unwrap();
<span class="kw">for </span>(k, v) <span class="kw">in </span>LdbIteratorIter::wrap(<span class="kw-2">&amp;mut </span>iter) {
<span class="kw">if let </span><span class="prelude-val">Some</span>(ev) = expected.get(<span class="kw-2">&amp;</span>k) {
<span class="macro">assert_eq!</span>(ev, <span class="kw-2">&amp;</span>v);
}
<span class="macro">assert!</span>(!non_existing.contains(<span class="kw-2">&amp;</span>k));
}
}
}
<span class="kw">fn </span>db_iter_allow_empty_key() {
<span class="kw">let </span>opt = options::for_test();
<span class="kw">let </span><span class="kw-2">mut </span>db = DB::open(<span class="string">&quot;db&quot;</span>, opt).unwrap();
<span class="macro">assert!</span>(db.new_iter().unwrap().next().is_none());
db.put(<span class="kw-2">&amp;</span>[], <span class="kw-2">&amp;</span>[]).unwrap();
<span class="macro">assert!</span>(db.new_iter().unwrap().next().is_some());
}
}
</code></pre></div>
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