feat: add bdk_sqlite_store crate implementing PersistBackend backed b…

…y a SQLite database

.gitignore

@@ -7,3 +7,4 @@ Cargo.lock
 
 # Example persisted files.
 *.db
+*.sqlite

Cargo.toml

@@ -4,6 +4,7 @@ members = [
     "crates/bdk",
     "crates/chain",
     "crates/file_store",
+    "crates/sqlite_store",
     "crates/electrum",
     "crates/esplora",
     "crates/bitcoind_rpc",

crates/sqlite_store/Cargo.toml

@@ -0,0 +1,22 @@
+[package]
+name = "bdk_sqlite_store"
+version = "0.1.0"
+edition = "2021"
+license = "MIT OR Apache-2.0"
+repository = "https://github.com/bitcoindevkit/bdk"
+documentation = "https://docs.rs/bdk_file_store"
+description = "A simple append-only SQLite based implementation of Persist for Bitcoin Dev Kit."
+keywords = ["bitcoin", "persist", "persistence", "bdk", "sqlite"]
+authors = ["Bitcoin Dev Kit Developers"]
+readme = "README.md"
+
+[dependencies]
+bdk_chain = { path = "../chain", version = "0.10.0", features = [ "serde", "miniscript" ] }
+rusqlite = { version = "0.31.0", features = ["bundled"]}
+serde = { version = "1", features = ["derive"] }
+serde_json =  "1"
+log = "0.4.21"
+hex = "0.4.3"
+
+[dev-dependencies]
+tempfile = "3"

crates/sqlite_store/README.md

@@ -0,0 +1,11 @@
+# BDK SQLite Store
+
+This is a simple append-only [SQLite] database backed implementation of
+[`Persist`](`bdk_chain::Persist`).
+
+The main structure is [`Store`](`crate::Store`), which can be used with [`bdk`]'s
+`Wallet` to persist wallet data into a SQLite database file.
+
+[`bdk`]: https://docs.rs/bdk/latest
+[`bdk_chain`]: https://docs.rs/bdk_chain/latest
+[SQLite]: https://www.sqlite.org/index.html

crates/sqlite_store/src/lib.rs

@@ -0,0 +1,81 @@
+#![doc = include_str!("../README.md")]
+
+mod store;
+
+use bdk_chain::{indexed_tx_graph, keychain, local_chain, Append, ConfirmationHeightAnchor};
+use serde::{Deserialize, Serialize};
+pub use store::*;
+
+#[derive(Clone, Debug, PartialEq)]
+struct ChangeSet<K: Ord + for<'de> Deserialize<'de> + Serialize>(
+    local_chain::ChangeSet,
+    indexed_tx_graph::ChangeSet<ConfirmationHeightAnchor, keychain::ChangeSet<K>>,
+);
+
+impl<K> Append for ChangeSet<K>
+where
+    K: Ord + for<'de> Deserialize<'de> + Serialize,
+{
+    fn append(&mut self, mut other: Self) {
+        self.0.append(&mut other.0);
+        self.1.append(other.1);
+    }
+
+    fn is_empty(&self) -> bool {
+        self.0.is_empty() && self.1.is_empty()
+    }
+}
+
+/// Error that occurs while writing new change sets to the DB.
+#[derive(Debug)]
+pub enum WriteError {
+    /// JSON encoding error.
+    Json(serde_json::Error),
+    /// SQLite error.
+    Sqlite(rusqlite::Error),
+}
+
+impl core::fmt::Display for WriteError {
+    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
+        match self {
+            Self::Json(e) => write!(f, "json error trying to write change set: {}", e),
+            Self::Sqlite(e) => write!(f, "sqlite error trying to write change set: {}", e),
+        }
+    }
+}
+
+impl From<serde_json::Error> for WriteError {
+    fn from(error: serde_json::Error) -> Self {
+        Self::Json(error)
+    }
+}
+
+impl std::error::Error for WriteError {}
+
+/// Error the occurs while reading stored change sets from the DB.
+#[derive(Debug)]
+pub enum ReadError {
+    /// Json decoding
+    Json {
+        rowid: usize,
+        err: serde_json::Error,
+    },
+    /// Sqlite error
+    Sqlite(rusqlite::Error),
+    /// FromSql error
+    FromSql(rusqlite::types::FromSqlError),
+}
+
+impl core::fmt::Display for ReadError {
+    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
+        match self {
+            ReadError::Json { rowid, err } => write!(
+                f,
+                "json error trying to decode change set {}, {}",
+                rowid, err
+            ),
+            ReadError::Sqlite(err) => write!(f, "Sqlite error {}", err),
+            ReadError::FromSql(err) => write!(f, "FromSql error {}", err),
+        }
+    }
+}