Resolves rust-lang#530 - add_package logic, make database calls in f…

…or loops

src/db/add_package.rs

@@ -1,4 +1,5 @@
 use std::{
+    collections::HashMap,
     fs,
     io::{BufRead, BufReader},
     path::Path,
@@ -316,28 +317,54 @@ fn add_keywords_into_database(
     pkg: &MetadataPackage,
     release_id: i32,
 ) -> Result<()> {
-    for keyword in &pkg.keywords {
-        let slug = slugify(&keyword);
-        let keyword_id: i32 = {
-            let rows = conn.query("SELECT id FROM keywords WHERE slug = $1", &[&slug])?;
-            if !rows.is_empty() {
-                rows[0].get(0)
-            } else {
-                conn.query(
-                    "INSERT INTO keywords (name, slug) VALUES ($1, $2) RETURNING id",
-                    &[&keyword, &slug],
-                )?[0]
-                    .get(0)
-            }
-        };
+    let wanted_keywords: HashMap<String, String> = pkg
+        .keywords
+        .iter()
+        .map(|kw| (slugify(&kw), kw.clone()))
+        .collect();
+
+    let mut existing_keyword_slugs: HashMap<String, i32> = conn
+        .query(
+            "SELECT slug, id FROM keywords WHERE slug IN $1",
+            &[&wanted_keywords.keys().collect::<Vec<_>>()],
+        )?
+        .iter()
+        .map(|row| (row.get("slug"), row.get("id")))
+        .collect();
 
-        // add releationship
-        let _ = conn.query(
-            "INSERT INTO keyword_rels (rid, kid) VALUES ($1, $2)",
-            &[&release_id, &keyword_id],
-        );
+    let new_keywords: Vec<(&String, &String)> = wanted_keywords
+        .iter()
+        .filter(|(k, _)| !(existing_keyword_slugs.contains_key(*k)))
+        .collect();
+
+    if !new_keywords.is_empty() {
+        // we create new keywords one-by-one, since most of the time we already have them,
+        // and because support for multi-record inserts is a mess without adding a new
+        // library
+        let insert_keyword_query =
+            conn.prepare("INSERT INTO keywords (name, slug) VALUES ($1, $2) RETURNING id")?;
+
+        for (slug, name) in new_keywords {
+            existing_keyword_slugs.insert(
+                slug.clone(),
+                conn.query_one(&insert_keyword_query, &[&name, &slug])?
+                    .get(0),
+            );
+        }
     }
 
+    conn.query(
+        "INSERT INTO keyword_rels (rid, kid) 
+        SELECT 
+            $1 as rid, 
+            id as kid 
+        FROM 
+            keywords 
+        WHERE
+            slug in $2",
+        &[&release_id, &wanted_keywords.keys().collect::<Vec<_>>()],
+    )?;
+
     Ok(())
 }