Port bin/update-crates over to Diesel

I thought we were done, but we're not... I forgot the binaries. Sorry.
:(

This one was pretty straightforward. There's a bit of refactoring in
here as well, and I moved some of the integrity checks that this code
was doing to the database. It's worth noting that the new body of
`set_updated_at` is identical to `diesel_set_updated_at`, but I can't
actually call that function from the other since it's `RETURNS trigger`.
Not sure if it's worth resolving, since the function is unlikely to
change.

Author: sgrif

migrations/20170706165855_dont_touch_timestamps_unless_row_changed/down.sql

@@ -0,0 +1,19 @@
+CREATE OR REPLACE FUNCTION set_updated_at() RETURNS trigger AS $$
+BEGIN
+    IF (NEW.updated_at IS NOT DISTINCT FROM OLD.updated_at) THEN
+        NEW.updated_at := current_timestamp;
+    END IF;
+    RETURN NEW;
+END
+$$ LANGUAGE plpgsql;
+
+CREATE OR REPLACE FUNCTION set_updated_at_ignore_downloads() RETURNS trigger AS $$
+BEGIN
+    IF (NEW.updated_at IS NOT DISTINCT FROM OLD.updated_at AND
+        NEW.downloads = OLD.downloads) THEN
+        NEW.updated_at := current_timestamp;
+    END IF;
+    RETURN NEW;
+END
+$$ LANGUAGE plpgsql;
+

migrations/20170706165855_dont_touch_timestamps_unless_row_changed/up.sql

@@ -0,0 +1,28 @@
+CREATE OR REPLACE FUNCTION set_updated_at() RETURNS trigger AS $$
+BEGIN
+    IF (
+        NEW IS DISTINCT FROM OLD AND
+        NEW.updated_at IS NOT DISTINCT FROM OLD.updated_at
+    ) THEN
+        NEW.updated_at = CURRENT_TIMESTAMP;
+    END IF;
+    RETURN NEW;
+END
+$$ LANGUAGE plpgsql;
+
+CREATE OR REPLACE FUNCTION set_updated_at_ignore_downloads() RETURNS trigger AS $$
+DECLARE
+    new_downloads integer;
+BEGIN
+    new_downloads := NEW.downloads;
+    OLD.downloads := NEW.downloads;
+    IF (
+        NEW IS DISTINCT FROM OLD AND
+        NEW.updated_at IS NOT DISTINCT FROM OLD.updated_at
+    ) THEN
+        NEW.updated_at = CURRENT_TIMESTAMP;
+    END IF;
+    NEW.downloads := new_downloads;
+    RETURN NEW;
+END
+$$ LANGUAGE plpgsql;

src/bin/delete-crate.rs

@@ -19,7 +19,7 @@ use cargo_registry::Crate;
 
 #[allow(dead_code)]
 fn main() {
-    let conn = cargo_registry::db::connect_now();
+    let conn = cargo_registry::db::connect_now_old();
     {
         let tx = conn.transaction().unwrap();
         delete(&tx);

src/bin/delete-version.rs

@@ -20,7 +20,7 @@ use cargo_registry::{Crate, Version};
 
 #[allow(dead_code)]
 fn main() {
-    let conn = cargo_registry::db::connect_now();
+    let conn = cargo_registry::db::connect_now_old();
     {
         let tx = conn.transaction().unwrap();
         delete(&tx);

src/bin/populate.rs

@@ -17,7 +17,7 @@ use rand::{StdRng, Rng};
 
 #[allow(dead_code)]
 fn main() {
-    let conn = cargo_registry::db::connect_now();
+    let conn = cargo_registry::db::connect_now_old();
     {
         let tx = conn.transaction().unwrap();
         update(&tx).unwrap();

src/bin/transfer-crates.rs

@@ -20,7 +20,7 @@ use cargo_registry::Model;
 
 #[allow(dead_code)]
 fn main() {
-    let conn = cargo_registry::db::connect_now();
+    let conn = cargo_registry::db::connect_now_old();
     {
         let tx = conn.transaction().unwrap();
         transfer(&tx);