Merge pull request #48 from dtolnay/findtimestamp

Add examples/find-timestamp.rs

Author: dtolnay

examples/find-timestamp.rs

@@ -0,0 +1,47 @@
+//! $ cargo run --release --example find-timestamp -- 2023-01-13T23:42:25.800721Z
+//! Reverse lookup what crate got published at a particular time. Useful for
+//! attributing discontinuities in a `cargo tally` graph.
+
+use chrono::DateTime;
+use db_dump::crates::CrateId;
+use semver::Version;
+use std::collections::BTreeMap as Map;
+use std::env;
+use std::io::{self, Write as _};
+use std::process;
+
+fn main() -> db_dump::Result<()> {
+    let mut query = Vec::new();
+    for arg in env::args_os().skip(1) {
+        let arg = arg.to_str().unwrap();
+        let datetime = DateTime::parse_from_rfc3339(arg).unwrap();
+        query.push(datetime.to_utc());
+    }
+
+    if query.is_empty() {
+        let _ = writeln!(
+            io::stderr(),
+            "Usage: cargo run --release --example find-timestamp -- 2023-01-13T23:42:25.800721Z",
+        );
+        process::exit(1);
+    }
+
+    let mut crates: Map<CrateId, String> = Map::new();
+    let mut versions: Vec<(CrateId, Version)> = Vec::new();
+    db_dump::Loader::new()
+        .crates(|row| {
+            crates.insert(row.id, row.name);
+        })
+        .versions(|row| {
+            if query.contains(&row.created_at) {
+                versions.push((row.crate_id, row.num));
+            }
+        })
+        .load("./db-dump.tar.gz")?;
+
+    for (crate_id, version) in versions {
+        println!("{} v{}", crates[&crate_id], version);
+    }
+
+    Ok(())
+}