| <!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/filter.rs`."><meta name="keywords" content="rust, rustlang, rust-lang"><title>filter.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>std::rc::Rc; |
| |
| <span class="kw">use </span>integer_encoding::FixedInt; |
| |
| <span class="doccomment">/// Encapsulates a filter algorithm allowing to search for keys more efficiently. |
| /// Usually, policies are used as a BoxedFilterPolicy (see below), so they |
| /// can be easily cloned and nested. |
| </span><span class="kw">pub trait </span>FilterPolicy { |
| <span class="doccomment">/// Returns a string identifying this policy. |
| </span><span class="kw">fn </span>name(<span class="kw-2">&</span><span class="self">self</span>) -> <span class="kw-2">&</span><span class="lifetime">'static </span>str; |
| <span class="doccomment">/// Create a filter matching the given keys. Keys are given as a long byte array that is |
| /// indexed by the offsets contained in key_offsets. |
| </span><span class="kw">fn </span>create_filter(<span class="kw-2">&</span><span class="self">self</span>, keys: <span class="kw-2">&</span>[u8], key_offsets: <span class="kw-2">&</span>[usize]) -> Vec<u8>; |
| <span class="doccomment">/// Check whether the given key may match the filter. |
| </span><span class="kw">fn </span>key_may_match(<span class="kw-2">&</span><span class="self">self</span>, key: <span class="kw-2">&</span>[u8], filter: <span class="kw-2">&</span>[u8]) -> bool; |
| } |
| |
| <span class="doccomment">/// A boxed and refcounted filter policy (reference-counted because a Box with unsized content |
| /// couldn't be cloned otherwise) |
| </span><span class="kw">pub type </span>BoxedFilterPolicy = Rc<Box<<span class="kw">dyn </span>FilterPolicy>>; |
| |
| <span class="kw">impl </span>FilterPolicy <span class="kw">for </span>BoxedFilterPolicy { |
| <span class="kw">fn </span>name(<span class="kw-2">&</span><span class="self">self</span>) -> <span class="kw-2">&</span><span class="lifetime">'static </span>str { |
| (<span class="kw-2">**</span><span class="self">self</span>).name() |
| } |
| <span class="kw">fn </span>create_filter(<span class="kw-2">&</span><span class="self">self</span>, keys: <span class="kw-2">&</span>[u8], key_offsets: <span class="kw-2">&</span>[usize]) -> Vec<u8> { |
| (<span class="kw-2">**</span><span class="self">self</span>).create_filter(keys, key_offsets) |
| } |
| <span class="kw">fn </span>key_may_match(<span class="kw-2">&</span><span class="self">self</span>, key: <span class="kw-2">&</span>[u8], filter: <span class="kw-2">&</span>[u8]) -> bool { |
| (<span class="kw-2">**</span><span class="self">self</span>).key_may_match(key, filter) |
| } |
| } |
| |
| <span class="doccomment">/// Used for tables that don't have filter blocks but need a type parameter. |
| </span><span class="attribute">#[derive(Clone)] |
| </span><span class="kw">pub struct </span>NoFilterPolicy; |
| |
| <span class="kw">impl </span>NoFilterPolicy { |
| <span class="kw">pub fn </span>new() -> NoFilterPolicy { |
| NoFilterPolicy |
| } |
| } |
| |
| <span class="kw">impl </span>FilterPolicy <span class="kw">for </span>NoFilterPolicy { |
| <span class="kw">fn </span>name(<span class="kw-2">&</span><span class="self">self</span>) -> <span class="kw-2">&</span><span class="lifetime">'static </span>str { |
| <span class="string">"_" |
| </span>} |
| <span class="kw">fn </span>create_filter(<span class="kw-2">&</span><span class="self">self</span>, <span class="kw">_</span>: <span class="kw-2">&</span>[u8], <span class="kw">_</span>: <span class="kw-2">&</span>[usize]) -> Vec<u8> { |
| <span class="macro">vec!</span>[] |
| } |
| <span class="kw">fn </span>key_may_match(<span class="kw-2">&</span><span class="self">self</span>, <span class="kw">_</span>: <span class="kw-2">&</span>[u8], <span class="kw">_</span>: <span class="kw-2">&</span>[u8]) -> bool { |
| <span class="bool-val">true |
| </span>} |
| } |
| |
| <span class="kw">const </span>BLOOM_SEED: u32 = <span class="number">0xbc9f1d34</span>; |
| |
| <span class="doccomment">/// A filter policy using a bloom filter internally. |
| </span><span class="attribute">#[derive(Clone)] |
| </span><span class="kw">pub struct </span>BloomPolicy { |
| bits_per_key: u32, |
| k: u32, |
| } |
| |
| <span class="doccomment">/// Beware the magic numbers... |
| </span><span class="kw">impl </span>BloomPolicy { |
| <span class="doccomment">/// Returns a new boxed BloomPolicy. |
| </span><span class="kw">pub fn </span>new(bits_per_key: u32) -> BloomPolicy { |
| BloomPolicy::new_unwrapped(bits_per_key) |
| } |
| |
| <span class="doccomment">/// Returns a new BloomPolicy with the given parameter. |
| </span><span class="kw">fn </span>new_unwrapped(bits_per_key: u32) -> BloomPolicy { |
| <span class="kw">let </span><span class="kw-2">mut </span>k = (bits_per_key <span class="kw">as </span>f32 * <span class="number">0.69</span>) <span class="kw">as </span>u32; |
| |
| <span class="kw">if </span>k < <span class="number">1 </span>{ |
| k = <span class="number">1</span>; |
| } <span class="kw">else if </span>k > <span class="number">30 </span>{ |
| k = <span class="number">30</span>; |
| } |
| |
| BloomPolicy { bits_per_key, k } |
| } |
| |
| <span class="kw">fn </span>bloom_hash(<span class="kw-2">&</span><span class="self">self</span>, data: <span class="kw-2">&</span>[u8]) -> u32 { |
| <span class="kw">let </span>m: u32 = <span class="number">0xc6a4a793</span>; |
| <span class="kw">let </span>r: u32 = <span class="number">24</span>; |
| |
| <span class="kw">let </span><span class="kw-2">mut </span>ix = <span class="number">0</span>; |
| <span class="kw">let </span>limit = data.len(); |
| |
| <span class="kw">let </span><span class="kw-2">mut </span>h: u32 = BLOOM_SEED ^ (limit <span class="kw">as </span>u64 * m <span class="kw">as </span>u64) <span class="kw">as </span>u32; |
| |
| <span class="kw">while </span>ix + <span class="number">4 </span><= limit { |
| <span class="kw">let </span>w = u32::decode_fixed(<span class="kw-2">&</span>data[ix..ix + <span class="number">4</span>]); |
| ix += <span class="number">4</span>; |
| |
| h = (h <span class="kw">as </span>u64 + w <span class="kw">as </span>u64) <span class="kw">as </span>u32; |
| h = (h <span class="kw">as </span>u64 * m <span class="kw">as </span>u64) <span class="kw">as </span>u32; |
| h ^= h >> <span class="number">16</span>; |
| } |
| |
| <span class="comment">// Process left-over bytes |
| </span><span class="macro">assert!</span>(limit - ix < <span class="number">4</span>); |
| |
| <span class="kw">if </span>limit - ix > <span class="number">0 </span>{ |
| <span class="kw">let </span><span class="kw-2">mut </span>i = <span class="number">0</span>; |
| |
| <span class="kw">for </span>b <span class="kw">in </span>data[ix..].iter() { |
| h = h.overflowing_add((<span class="kw-2">*</span>b <span class="kw">as </span>u32) << (<span class="number">8 </span>* i)).<span class="number">0</span>; |
| i += <span class="number">1</span>; |
| } |
| |
| h = (h <span class="kw">as </span>u64 * m <span class="kw">as </span>u64) <span class="kw">as </span>u32; |
| h ^= h >> r; |
| } |
| h |
| } |
| } |
| |
| <span class="kw">impl </span>FilterPolicy <span class="kw">for </span>BloomPolicy { |
| <span class="kw">fn </span>name(<span class="kw-2">&</span><span class="self">self</span>) -> <span class="kw-2">&</span><span class="lifetime">'static </span>str { |
| <span class="string">"leveldb.BuiltinBloomFilter2" |
| </span>} |
| <span class="kw">fn </span>create_filter(<span class="kw-2">&</span><span class="self">self</span>, keys: <span class="kw-2">&</span>[u8], key_offsets: <span class="kw-2">&</span>[usize]) -> Vec<u8> { |
| <span class="kw">let </span>filter_bits = key_offsets.len() * <span class="self">self</span>.bits_per_key <span class="kw">as </span>usize; |
| <span class="kw">let </span><span class="kw-2">mut </span>filter: Vec<u8>; |
| |
| <span class="kw">if </span>filter_bits < <span class="number">64 </span>{ |
| filter = Vec::with_capacity(<span class="number">8 </span>+ <span class="number">1</span>); |
| filter.resize(<span class="number">8</span>, <span class="number">0</span>); |
| } <span class="kw">else </span>{ |
| filter = Vec::with_capacity(<span class="number">1 </span>+ ((filter_bits + <span class="number">7</span>) / <span class="number">8</span>)); |
| filter.resize((filter_bits + <span class="number">7</span>) / <span class="number">8</span>, <span class="number">0</span>); |
| } |
| |
| <span class="kw">let </span>adj_filter_bits = (filter.len() * <span class="number">8</span>) <span class="kw">as </span>u32; |
| |
| <span class="comment">// Encode k at the end of the filter. |
| </span>filter.push(<span class="self">self</span>.k <span class="kw">as </span>u8); |
| |
| <span class="comment">// Add all keys to the filter. |
| </span>offset_data_iterate(keys, key_offsets, |key| { |
| <span class="kw">let </span><span class="kw-2">mut </span>h = <span class="self">self</span>.bloom_hash(key); |
| <span class="kw">let </span>delta = (h >> <span class="number">17</span>) | (h << <span class="number">15</span>); |
| <span class="kw">for _ in </span><span class="number">0</span>..<span class="self">self</span>.k { |
| <span class="kw">let </span>bitpos = (h % adj_filter_bits) <span class="kw">as </span>usize; |
| filter[bitpos / <span class="number">8</span>] |= <span class="number">1 </span><< (bitpos % <span class="number">8</span>); |
| h = (h <span class="kw">as </span>u64 + delta <span class="kw">as </span>u64) <span class="kw">as </span>u32; |
| } |
| }); |
| |
| filter |
| } |
| <span class="kw">fn </span>key_may_match(<span class="kw-2">&</span><span class="self">self</span>, key: <span class="kw-2">&</span>[u8], filter: <span class="kw-2">&</span>[u8]) -> bool { |
| <span class="kw">if </span>filter.len() == <span class="number">0 </span>{ |
| <span class="kw">return </span><span class="bool-val">true</span>; |
| } |
| |
| <span class="kw">let </span>bits = (filter.len() - <span class="number">1</span>) <span class="kw">as </span>u32 * <span class="number">8</span>; |
| <span class="kw">let </span>k = filter[filter.len() - <span class="number">1</span>]; |
| <span class="kw">let </span>filter_adj = <span class="kw-2">&</span>filter[<span class="number">0</span>..filter.len() - <span class="number">1</span>]; |
| |
| <span class="kw">if </span>k > <span class="number">30 </span>{ |
| <span class="kw">return </span><span class="bool-val">true</span>; |
| } |
| |
| <span class="kw">let </span><span class="kw-2">mut </span>h = <span class="self">self</span>.bloom_hash(key); |
| <span class="kw">let </span>delta = (h >> <span class="number">17</span>) | (h << <span class="number">15</span>); |
| <span class="kw">for _ in </span><span class="number">0</span>..k { |
| <span class="kw">let </span>bitpos = (h % bits) <span class="kw">as </span>usize; |
| <span class="kw">if </span>(filter_adj[bitpos / <span class="number">8</span>] & (<span class="number">1 </span><< (bitpos % <span class="number">8</span>))) == <span class="number">0 </span>{ |
| <span class="kw">return </span><span class="bool-val">false</span>; |
| } |
| h = (h <span class="kw">as </span>u64 + delta <span class="kw">as </span>u64) <span class="kw">as </span>u32; |
| } |
| <span class="bool-val">true |
| </span>} |
| } |
| |
| <span class="doccomment">/// A filter policy wrapping another policy; extracting the user key from internal keys for all |
| /// operations. |
| /// A User Key is u8*. |
| /// An Internal Key is u8* u8{8} (where the second part encodes a tag and a sequence number). |
| </span><span class="attribute">#[derive(Clone)] |
| </span><span class="kw">pub struct </span>InternalFilterPolicy<FP: FilterPolicy> { |
| internal: FP, |
| } |
| |
| <span class="kw">impl</span><FP: FilterPolicy> InternalFilterPolicy<FP> { |
| <span class="kw">pub fn </span>new(inner: FP) -> InternalFilterPolicy<FP> { |
| InternalFilterPolicy { internal: inner } |
| } |
| } |
| |
| <span class="kw">impl</span><FP: FilterPolicy> FilterPolicy <span class="kw">for </span>InternalFilterPolicy<FP> { |
| <span class="kw">fn </span>name(<span class="kw-2">&</span><span class="self">self</span>) -> <span class="kw-2">&</span><span class="lifetime">'static </span>str { |
| <span class="self">self</span>.internal.name() |
| } |
| |
| <span class="kw">fn </span>create_filter(<span class="kw-2">&</span><span class="self">self</span>, keys: <span class="kw-2">&</span>[u8], key_offsets: <span class="kw-2">&</span>[usize]) -> Vec<u8> { |
| <span class="kw">let </span><span class="kw-2">mut </span>mod_keys = Vec::with_capacity(keys.len() - key_offsets.len() * <span class="number">8</span>); |
| <span class="kw">let </span><span class="kw-2">mut </span>mod_key_offsets = Vec::with_capacity(key_offsets.len()); |
| |
| offset_data_iterate(keys, key_offsets, |key| { |
| mod_key_offsets.push(mod_keys.len()); |
| mod_keys.extend_from_slice(<span class="kw-2">&</span>key[<span class="number">0</span>..key.len() - <span class="number">8</span>]); |
| }); |
| <span class="self">self</span>.internal.create_filter(<span class="kw-2">&</span>mod_keys, <span class="kw-2">&</span>mod_key_offsets) |
| } |
| |
| <span class="kw">fn </span>key_may_match(<span class="kw-2">&</span><span class="self">self</span>, key: <span class="kw-2">&</span>[u8], filter: <span class="kw-2">&</span>[u8]) -> bool { |
| <span class="self">self</span>.internal.key_may_match(<span class="kw-2">&</span>key[<span class="number">0</span>..key.len() - <span class="number">8</span>], filter) |
| } |
| } |
| |
| <span class="doccomment">/// offset_data_iterate iterates over the entries in data that are indexed by the offsets given in |
| /// offsets. This is e.g. the internal format of a FilterBlock. |
| </span><span class="kw">fn </span>offset_data_iterate<F: FnMut(<span class="kw-2">&</span>[u8])>(data: <span class="kw-2">&</span>[u8], offsets: <span class="kw-2">&</span>[usize], <span class="kw-2">mut </span>f: F) { |
| <span class="kw">for </span>offix <span class="kw">in </span><span class="number">0</span>..offsets.len() { |
| <span class="kw">let </span>upper = <span class="kw">if </span>offix == offsets.len() - <span class="number">1 </span>{ |
| data.len() |
| } <span class="kw">else </span>{ |
| offsets[offix + <span class="number">1</span>] |
| }; |
| <span class="kw">let </span>piece = <span class="kw-2">&</span>data[offsets[offix]..upper]; |
| f(piece); |
| } |
| } |
| |
| <span class="attribute">#[cfg(feature = <span class="string">"enclave_unit_test"</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>::key_types::LookupKey; |
| <span class="kw">use </span>teaclave_test_utils::<span class="kw-2">*</span>; |
| |
| <span class="kw">pub fn </span>run_tests() -> bool { |
| <span class="macro">run_tests!</span>( |
| test_filter_bloom, |
| test_filter_internal_keys_identical, |
| test_filter_bloom_hash, |
| ) |
| } |
| |
| <span class="kw">const </span>_BITS_PER_KEY: u32 = <span class="number">12</span>; |
| |
| <span class="kw">fn </span>input_data() -> (Vec<u8>, Vec<usize>) { |
| <span class="kw">let </span><span class="kw-2">mut </span>concat = <span class="macro">vec!</span>[]; |
| <span class="kw">let </span><span class="kw-2">mut </span>offs = <span class="macro">vec!</span>[]; |
| |
| <span class="kw">for </span>d <span class="kw">in </span>[ |
| <span class="string">"abc123def456"</span>.as_bytes(), |
| <span class="string">"xxx111xxx222"</span>.as_bytes(), |
| <span class="string">"ab00cd00ab"</span>.as_bytes(), |
| <span class="string">"908070605040302010"</span>.as_bytes(), |
| ] |
| .iter() |
| { |
| offs.push(concat.len()); |
| concat.extend_from_slice(d); |
| } |
| (concat, offs) |
| } |
| |
| <span class="doccomment">/// Creates a filter using the keys from input_data(). |
| </span><span class="kw">fn </span>create_filter() -> Vec<u8> { |
| <span class="kw">let </span>fpol = BloomPolicy::new(_BITS_PER_KEY); |
| <span class="kw">let </span>(data, offs) = input_data(); |
| <span class="kw">let </span>filter = fpol.create_filter(<span class="kw-2">&</span>data, <span class="kw-2">&</span>offs); |
| |
| <span class="macro">assert_eq!</span>(filter, <span class="macro">vec!</span>[<span class="number">194</span>, <span class="number">148</span>, <span class="number">129</span>, <span class="number">140</span>, <span class="number">192</span>, <span class="number">196</span>, <span class="number">132</span>, <span class="number">164</span>, <span class="number">8</span>]); |
| filter |
| } |
| |
| <span class="doccomment">/// Creates a filter using the keys from input_data() but converted to InternalKey format. |
| </span><span class="kw">fn </span>create_internalkey_filter() -> Vec<u8> { |
| <span class="kw">let </span>fpol = Rc::new(Box::new(InternalFilterPolicy::new(BloomPolicy::new( |
| _BITS_PER_KEY, |
| )))); |
| <span class="kw">let </span>(data, offs) = input_data(); |
| <span class="kw">let </span>(<span class="kw-2">mut </span>intdata, <span class="kw-2">mut </span>intoffs) = (<span class="macro">vec!</span>[], <span class="macro">vec!</span>[]); |
| |
| offset_data_iterate(<span class="kw-2">&</span>data, <span class="kw-2">&</span>offs, |key| { |
| <span class="kw">let </span>ikey = LookupKey::new(key, <span class="number">123</span>); |
| intoffs.push(intdata.len()); |
| intdata.extend_from_slice(ikey.internal_key()); |
| }); |
| <span class="kw">let </span>filter = fpol.create_filter(<span class="kw-2">&</span>intdata, <span class="kw-2">&</span>intoffs); |
| |
| filter |
| } |
| |
| <span class="kw">fn </span>test_filter_bloom() { |
| <span class="kw">let </span>f = create_filter(); |
| <span class="kw">let </span>fp = BloomPolicy::new(_BITS_PER_KEY); |
| <span class="kw">let </span>(data, offs) = input_data(); |
| |
| offset_data_iterate(<span class="kw-2">&</span>data, <span class="kw-2">&</span>offs, |key| { |
| <span class="macro">assert!</span>(fp.key_may_match(key, <span class="kw-2">&</span>f)); |
| }); |
| } |
| |
| <span class="doccomment">/// This test verifies that InternalFilterPolicy works correctly. |
| </span><span class="kw">fn </span>test_filter_internal_keys_identical() { |
| <span class="macro">assert_eq!</span>(create_filter(), create_internalkey_filter()); |
| } |
| |
| <span class="kw">fn </span>test_filter_bloom_hash() { |
| <span class="kw">let </span>d1 = <span class="macro">vec!</span>[<span class="number">0x62</span>]; |
| <span class="kw">let </span>d2 = <span class="macro">vec!</span>[<span class="number">0xc3</span>, <span class="number">0x97</span>]; |
| <span class="kw">let </span>d3 = <span class="macro">vec!</span>[<span class="number">0xe2</span>, <span class="number">0x99</span>, <span class="number">0xa5</span>]; |
| <span class="kw">let </span>d4 = <span class="macro">vec!</span>[<span class="number">0xe1</span>, <span class="number">0x80</span>, <span class="number">0xb9</span>, <span class="number">0x32</span>]; |
| |
| <span class="kw">let </span>fp = BloomPolicy::new_unwrapped(_BITS_PER_KEY); |
| |
| <span class="macro">assert_eq!</span>(fp.bloom_hash(<span class="kw-2">&</span>d1), <span class="number">0xef1345c4</span>); |
| <span class="macro">assert_eq!</span>(fp.bloom_hash(<span class="kw-2">&</span>d2), <span class="number">0x5b663814</span>); |
| <span class="macro">assert_eq!</span>(fp.bloom_hash(<span class="kw-2">&</span>d3), <span class="number">0x323c078f</span>); |
| <span class="macro">assert_eq!</span>(fp.bloom_hash(<span class="kw-2">&</span>d4), <span class="number">0xed21633a</span>); |
| } |
| } |
| </code></pre></div> |
| </section></div></main><div id="rustdoc-vars" data-root-path="../../" data-current-crate="rusty_leveldb" data-themes="ayu,dark,light" data-resource-suffix="" data-rustdoc-version="1.66.0-nightly (5c8bff74b 2022-10-21)" ></div></body></html> |
