1 <!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="API documentation for the Rust `coin_selection` mod in crate `bdk`."><meta name="keywords" content="rust, rustlang, rust-lang, coin_selection"><title>bdk::wallet::coin_selection - Rust</title><link rel="stylesheet" type="text/css" href="../../../normalize.css"><link rel="stylesheet" type="text/css" href="../../../rustdoc.css" id="mainThemeStyle"><link rel="stylesheet" type="text/css" href="../../../light.css" id="themeStyle"><link rel="stylesheet" type="text/css" href="../../../dark.css" disabled ><link rel="stylesheet" type="text/css" href="../../../ayu.css" disabled ><script id="default-settings"></script><script src="../../../storage.js"></script><noscript><link rel="stylesheet" href="../../../noscript.css"></noscript><link rel="icon" type="image/svg+xml" href="../../../favicon.svg">
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3 <link rel="alternate icon" type="image/png" href="../../../favicon-32x32.png"><style type="text/css">#crate-search{background-image:url("../../../down-arrow.svg");}</style></head><body class="rustdoc mod"><!--[if lte IE 8]><div class="warning">This old browser is unsupported and will most likely display funky things.</div><![endif]--><nav class="sidebar"><div class="sidebar-menu">☰</div><a href='../../../bdk/index.html'><div class='logo-container rust-logo'><img src='../../../rust-logo.png' alt='logo'></div></a><p class="location">Module coin_selection</p><div class="sidebar-elems"><div class="block items"><ul><li><a href="#structs">Structs</a></li><li><a href="#traits">Traits</a></li><li><a href="#types">Type Definitions</a></li></ul></div><p class="location"><a href="../../index.html">bdk</a>::<wbr><a href="../index.html">wallet</a></p><script>window.sidebarCurrent = {name: "coin_selection", ty: "mod", relpath: "../"};</script><script defer src="../sidebar-items.js"></script></div></nav><div class="theme-picker"><button id="theme-picker" aria-label="Pick another theme!" aria-haspopup="menu"><img src="../../../brush.svg" width="18" alt="Pick another theme!"></button><div id="theme-choices" role="menu"></div></div><script src="../../../theme.js"></script><nav class="sub"><form class="search-form"><div class="search-container"><div><select id="crate-search"><option value="All crates">All crates</option></select><input class="search-input" name="search" disabled autocomplete="off" spellcheck="false" placeholder="Click or press ‘S’ to search, ‘?’ for more options…" type="search"></div><button type="button" class="help-button">?</button>
4 <a id="settings-menu" href="../../../settings.html"><img src="../../../wheel.svg" width="18" alt="Change settings"></a></div></form></nav><section id="main" class="content"><h1 class="fqn"><span class="out-of-band"><span id="render-detail"><a id="toggle-all-docs" href="javascript:void(0)" title="collapse all docs">[<span class="inner">−</span>]</a></span><a class="srclink" href="../../../src/bdk/wallet/coin_selection.rs.html#25-997" title="goto source code">[src]</a></span><span class="in-band">Module <a href="../../index.html">bdk</a>::<wbr><a href="../index.html">wallet</a>::<wbr><a class="mod" href="">coin_selection</a></span></h1><div class="docblock"><p>Coin selection</p>
5 <p>This module provides the trait <a href="../../../bdk/wallet/coin_selection/trait.CoinSelectionAlgorithm.html" title="CoinSelectionAlgorithm"><code>CoinSelectionAlgorithm</code></a> that can be implemented to
6 define custom coin selection algorithms.</p>
7 <p>The coin selection algorithm is not globally part of a <a href="../../../bdk/wallet/struct.Wallet.html"><code>Wallet</code></a>, instead it
8 is selected whenever a <a href="../../../bdk/wallet/struct.Wallet.html#method.create_tx"><code>Wallet::create_tx</code></a> call is made, through
9 the use of the <a href="../../../bdk/wallet/tx_builder/struct.TxBuilder.html"><code>TxBuilder</code></a> structure, specifically with
10 <a href="../../../bdk/wallet/tx_builder/struct.TxBuilder.html#method.coin_selection"><code>TxBuilder::coin_selection</code></a> method.</p>
11 <p>The <a href="../../../bdk/wallet/coin_selection/type.DefaultCoinSelectionAlgorithm.html" title="DefaultCoinSelectionAlgorithm"><code>DefaultCoinSelectionAlgorithm</code></a> selects the default coin selection algorithm that
12 <a href="../../../bdk/wallet/tx_builder/struct.TxBuilder.html"><code>TxBuilder</code></a> uses, if it's not explicitly overridden.</p>
13 <h2 id="example" class="section-header"><a href="#example">Example</a></h2>
14 <div class="example-wrap"><pre class="rust rust-example-rendered">
15 <span class="attribute">#[<span class="ident">derive</span>(<span class="ident">Debug</span>)]</span>
16 <span class="kw">struct</span> <span class="ident">AlwaysSpendEverything</span>;
18 <span class="kw">impl</span><span class="op"><</span><span class="ident">D</span>: <span class="ident">Database</span><span class="op">></span> <span class="ident">CoinSelectionAlgorithm</span><span class="op"><</span><span class="ident">D</span><span class="op">></span> <span class="kw">for</span> <span class="ident">AlwaysSpendEverything</span> {
19 <span class="kw">fn</span> <span class="ident">coin_select</span>(
20 <span class="kw-2">&</span><span class="self">self</span>,
21 <span class="ident">database</span>: <span class="kw-2">&</span><span class="ident">D</span>,
22 <span class="ident">required_utxos</span>: <span class="ident">Vec</span><span class="op"><</span>(<span class="ident">UTXO</span>, <span class="ident">usize</span>)<span class="op">></span>,
23 <span class="ident">optional_utxos</span>: <span class="ident">Vec</span><span class="op"><</span>(<span class="ident">UTXO</span>, <span class="ident">usize</span>)<span class="op">></span>,
24 <span class="ident">fee_rate</span>: <span class="ident">FeeRate</span>,
25 <span class="ident">amount_needed</span>: <span class="ident">u64</span>,
26 <span class="ident">fee_amount</span>: <span class="ident">f32</span>,
27 ) <span class="op">-</span><span class="op">></span> <span class="prelude-ty">Result</span><span class="op"><</span><span class="ident">CoinSelectionResult</span>, <span class="ident">bdk</span>::<span class="ident">Error</span><span class="op">></span> {
28 <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">selected_amount</span> <span class="op">=</span> <span class="number">0</span>;
29 <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">additional_weight</span> <span class="op">=</span> <span class="number">0</span>;
30 <span class="kw">let</span> <span class="ident">all_utxos_selected</span> <span class="op">=</span> <span class="ident">required_utxos</span>
31 .<span class="ident">into_iter</span>().<span class="ident">chain</span>(<span class="ident">optional_utxos</span>)
32 .<span class="ident">scan</span>((<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">selected_amount</span>, <span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">additional_weight</span>), <span class="op">|</span>(<span class="ident">selected_amount</span>, <span class="ident">additional_weight</span>), (<span class="ident">utxo</span>, <span class="ident">weight</span>)<span class="op">|</span> {
33 <span class="kw-2">*</span><span class="kw-2">*</span><span class="ident">selected_amount</span> <span class="op">+</span><span class="op">=</span> <span class="ident">utxo</span>.<span class="ident">txout</span>.<span class="ident">value</span>;
34 <span class="kw-2">*</span><span class="kw-2">*</span><span class="ident">additional_weight</span> <span class="op">+</span><span class="op">=</span> <span class="ident">TXIN_BASE_WEIGHT</span> <span class="op">+</span> <span class="ident">weight</span>;
36 <span class="prelude-val">Some</span>(<span class="ident">utxo</span>)
38 .<span class="ident">collect</span>::<span class="op"><</span><span class="ident">Vec</span><span class="op"><</span><span class="kw">_</span><span class="op">></span><span class="op">></span>();
39 <span class="kw">let</span> <span class="ident">additional_fees</span> <span class="op">=</span> <span class="ident">additional_weight</span> <span class="kw">as</span> <span class="ident">f32</span> <span class="op">*</span> <span class="ident">fee_rate</span>.<span class="ident">as_sat_vb</span>() <span class="op">/</span> <span class="number">4.0</span>;
41 <span class="kw">if</span> (<span class="ident">fee_amount</span> <span class="op">+</span> <span class="ident">additional_fees</span>).<span class="ident">ceil</span>() <span class="kw">as</span> <span class="ident">u64</span> <span class="op">+</span> <span class="ident">amount_needed</span> <span class="op">></span> <span class="ident">selected_amount</span> {
42 <span class="kw">return</span> <span class="prelude-val">Err</span>(<span class="ident">bdk</span>::<span class="ident">Error</span>::<span class="ident">InsufficientFunds</span>);
45 <span class="prelude-val">Ok</span>(<span class="ident">CoinSelectionResult</span> {
46 <span class="ident">selected</span>: <span class="ident">all_utxos_selected</span>,
47 <span class="ident">selected_amount</span>,
48 <span class="ident">fee_amount</span>: <span class="ident">fee_amount</span> <span class="op">+</span> <span class="ident">additional_fees</span>,
53 <span class="comment">// create wallet, sync, ...</span>
55 <span class="kw">let</span> <span class="ident">to_address</span> <span class="op">=</span> <span class="ident">Address</span>::<span class="ident">from_str</span>(<span class="string">"2N4eQYCbKUHCCTUjBJeHcJp9ok6J2GZsTDt"</span>).<span class="ident">unwrap</span>();
56 <span class="kw">let</span> (<span class="ident">psbt</span>, <span class="ident">details</span>) <span class="op">=</span> <span class="ident">wallet</span>.<span class="ident">create_tx</span>(
57 <span class="ident">TxBuilder</span>::<span class="ident">with_recipients</span>(<span class="macro">vec</span><span class="macro">!</span>[(<span class="ident">to_address</span>.<span class="ident">script_pubkey</span>(), <span class="number">50_000</span>)])
58 .<span class="ident">coin_selection</span>(<span class="ident">AlwaysSpendEverything</span>),
59 )<span class="question-mark">?</span>;
61 <span class="comment">// inspect, sign, broadcast, ...</span>
63 </div><h2 id="structs" class="section-header"><a href="#structs">Structs</a></h2>
64 <table><tr class="module-item"><td><a class="struct" href="struct.BranchAndBoundCoinSelection.html" title="bdk::wallet::coin_selection::BranchAndBoundCoinSelection struct">BranchAndBoundCoinSelection</a></td><td class="docblock-short"><p>Branch and bound coin selection</p>
65 </td></tr><tr class="module-item"><td><a class="struct" href="struct.CoinSelectionResult.html" title="bdk::wallet::coin_selection::CoinSelectionResult struct">CoinSelectionResult</a></td><td class="docblock-short"><p>Result of a successful coin selection</p>
66 </td></tr><tr class="module-item"><td><a class="struct" href="struct.LargestFirstCoinSelection.html" title="bdk::wallet::coin_selection::LargestFirstCoinSelection struct">LargestFirstCoinSelection</a></td><td class="docblock-short"><p>Simple and dumb coin selection</p>
67 </td></tr></table><h2 id="traits" class="section-header"><a href="#traits">Traits</a></h2>
68 <table><tr class="module-item"><td><a class="trait" href="trait.CoinSelectionAlgorithm.html" title="bdk::wallet::coin_selection::CoinSelectionAlgorithm trait">CoinSelectionAlgorithm</a></td><td class="docblock-short"><p>Trait for generalized coin selection algorithms</p>
69 </td></tr></table><h2 id="types" class="section-header"><a href="#types">Type Definitions</a></h2>
70 <table><tr class="module-item"><td><a class="type" href="type.DefaultCoinSelectionAlgorithm.html" title="bdk::wallet::coin_selection::DefaultCoinSelectionAlgorithm type">DefaultCoinSelectionAlgorithm</a></td><td class="docblock-short"><p>Default coin selection algorithm used by <a href="../../../bdk/wallet/tx_builder/struct.TxBuilder.html"><code>TxBuilder</code></a> if not
72 </td></tr></table></section><section id="search" class="content hidden"></section><section class="footer"></section><script>window.rootPath = "../../../";window.currentCrate = "bdk";</script><script src="../../../main.js"></script><script defer src="../../../search-index.js"></script></body></html>
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