1 files changed, 76 insertions, 0 deletions
diff --git a/third_party/rust/rkv/examples/iterator.rs b/third_party/rust/rkv/examples/iterator.rs
new file mode 100644
index 0000000000..445dc37c28
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+++ b/third_party/rust/rkv/examples/iterator.rs
@@ -0,0 +1,76 @@
+// Any copyright is dedicated to the Public Domain.
+// http://creativecommons.org/publicdomain/zero/1.0/
+
+//! A demo that showcases the basic usage of iterators in rkv.
+//!
+//! You can test this out by running:
+//!
+//!     cargo run --example iterator
+
+use std::{fs, str};
+
+use tempfile::Builder;
+
+use rkv::{
+    backend::{SafeMode, SafeModeDatabase, SafeModeEnvironment},
+    Manager, Rkv, SingleStore, StoreError, StoreOptions, Value,
+};
+
+fn main() {
+    let root = Builder::new().prefix("iterator").tempdir().unwrap();
+    fs::create_dir_all(root.path()).unwrap();
+    let p = root.path();
+
+    let mut manager = Manager::<SafeModeEnvironment>::singleton().write().unwrap();
+    let created_arc = manager.get_or_create(p, Rkv::new::<SafeMode>).unwrap();
+    let k = created_arc.read().unwrap();
+    let store = k.open_single("store", StoreOptions::create()).unwrap();
+
+    populate_store(&k, store).unwrap();
+
+    let reader = k.read().unwrap();
+
+    println!("Iterating from the beginning...");
+    // Reader::iter_start() iterates from the first item in the store, and
+    // returns the (key, value) tuples in order.
+    let mut iter = store.iter_start(&reader).unwrap();
+    while let Some(Ok((country, city))) = iter.next() {
+        let country = str::from_utf8(country).unwrap();
+        println!("{country}, {city:?}");
+    }
+
+    println!();
+    println!("Iterating from the given key...");
+    // Reader::iter_from() iterates from the first key equal to or greater
+    // than the given key.
+    let mut iter = store.iter_from(&reader, "Japan").unwrap();
+    while let Some(Ok((country, city))) = iter.next() {
+        println!("{}, {city:?}", str::from_utf8(country).unwrap());
+    }
+
+    println!();
+    println!("Iterating from the given prefix...");
+    let mut iter = store.iter_from(&reader, "Un").unwrap();
+    while let Some(Ok((country, city))) = iter.next() {
+        println!("{}, {city:?}", str::from_utf8(country).unwrap());
+    }
+}
+
+fn populate_store(
+    k: &Rkv<SafeModeEnvironment>,
+    store: SingleStore<SafeModeDatabase>,
+) -> Result<(), StoreError> {
+    let mut writer = k.write()?;
+    for (country, city) in vec![
+        ("Canada", Value::Str("Ottawa")),
+        ("United States of America", Value::Str("Washington")),
+        ("Germany", Value::Str("Berlin")),
+        ("France", Value::Str("Paris")),
+        ("Italy", Value::Str("Rome")),
+        ("United Kingdom", Value::Str("London")),
+        ("Japan", Value::Str("Tokyo")),
+    ] {
+        store.put(&mut writer, country, &city)?;
+    }
+    writer.commit()
+}