database/memory: cleaner update_post implementation

This one manages to avoid extraneous allocations as much as possible,
by deconstructing the update into pieces and using a mutable reference
taken directly from the hashmap in which the posts are stored.

Now if only this hashmap were to be serialized on Drop, we could even
have persistence in the database and therefore gain another backend
that requires no dependencies to run, just like FileStorage, but
avoids extraneous file access (or maybe shunts it into the
background?)

1 files changed, 70 insertions, 1 deletions

diff --git a/kittybox-rs/src/database/memory.rs b/kittybox-rs/src/database/memory.rs
index ce98d05..26d3095 100644
--- a/kittybox-rs/src/database/memory.rs
+++ b/kittybox-rs/src/database/memory.rs
@@ -89,7 +89,76 @@ impl Storage for MemoryStorage {
     }
 
     async fn update_post(&self, url: &'_ str, update: crate::micropub::MicropubUpdate) -> Result<()> {
-        todo!()
+        let mut guard = self.mapping.write().await;
+        let mut post = guard.get_mut(url).ok_or(StorageError::from_static(ErrorKind::NotFound, "The specified post wasn't found in the database."))?;
+
+        use crate::micropub::MicropubPropertyDeletion;
+
+        let mut add_keys: HashMap<String, Vec<serde_json::Value>> = HashMap::new();
+        let mut remove_keys: Vec<String> = vec![];
+        let mut remove_values: HashMap<String, Vec<serde_json::Value>> = HashMap::new();
+
+        if let Some(MicropubPropertyDeletion::Properties(delete)) = update.delete {
+            remove_keys.extend(delete.iter().cloned());
+        } else if let Some(MicropubPropertyDeletion::Values(delete)) = update.delete {
+            for (k, v) in delete {
+                remove_values
+                    .entry(k.to_string())
+                    .or_default()
+                    .extend(v.clone());
+            }
+        }
+        if let Some(add) = update.add {
+            for (k, v) in add {
+                add_keys.insert(k.to_string(), v.clone());
+            }
+        }
+        if let Some(replace) = update.replace {
+            for (k, v) in replace {
+                remove_keys.push(k.to_string());
+                add_keys.insert(k.to_string(), v.clone());
+            }
+        }
+
+        if let Some(props) = post["properties"].as_object_mut() {
+            for k in remove_keys {
+                props.remove(&k);
+            }
+        }
+        for (k, v) in remove_values {
+            let k = &k;
+            let props = if k == "children" {
+                &mut post
+            } else {
+                &mut post["properties"]
+            };
+            v.iter().for_each(|v| {
+                if let Some(vec) = props[k].as_array_mut() {
+                    if let Some(index) = vec.iter().position(|w| w == v) {
+                        vec.remove(index);
+                    }
+                }
+            });
+        }
+        for (k, v) in add_keys {
+            tracing::debug!("Adding k/v to post: {} => {:?}", k, v);
+            let props = if k == "children" {
+                &mut post
+            } else {
+                &mut post["properties"]
+            };
+            if let Some(prop) = props[&k].as_array_mut() {
+                if k == "children" {
+                    v.into_iter().rev().for_each(|v| prop.insert(0, v));
+                } else {
+                    prop.extend(v.into_iter());
+                }
+            } else {
+                props[&k] = serde_json::Value::Array(v)
+            }
+        }
+
+        Ok(())
     }
 
     async fn get_channels(&self, user: &'_ str) -> Result<Vec<MicropubChannel>> {