Initial commit

src/jmap/blob.rs

@@ -0,0 +1,93 @@
+/*
+ * SPDX-FileCopyrightText: 2020 Stalwart Labs LLC <[email protected]>
+ *
+ * SPDX-License-Identifier: Apache-2.0 OR MIT
+ */
+
+use serde_json::{Map, Value};
+
+pub const SENTINEL_KEY: &str = "@blob";
+
+pub fn import_blob_ids<F>(value: &mut Value, mut resolve: F) -> Result<(), BlobWalkError>
+where
+    F: FnMut(&str) -> Result<i64, BlobWalkError>,
+{
+    walk_import(value, &mut resolve)
+}
+
+fn walk_import<F>(value: &mut Value, resolve: &mut F) -> Result<(), BlobWalkError>
+where
+    F: FnMut(&str) -> Result<i64, BlobWalkError>,
+{
+    match value {
+        Value::Object(map) => {
+
+            if let Some(Value::String(blob_id)) = map.remove("blobId") {
+                let local = resolve(&blob_id)?;
+                map.insert(SENTINEL_KEY.to_owned(), Value::from(local));
+            }
+            for child in map.values_mut() {
+                walk_import(child, resolve)?;
+            }
+        }
+        Value::Array(items) => {
+            for item in items {
+                walk_import(item, resolve)?;
+            }
+        }
+        _ => {}
+    }
+    Ok(())
+}
+
+pub fn export_blob_ids<F>(value: &mut Value, mut resolve: F) -> Result<(), BlobWalkError>
+where
+    F: FnMut(i64) -> Result<String, BlobWalkError>,
+{
+    walk_export(value, &mut resolve)
+}
+
+fn walk_export<F>(value: &mut Value, resolve: &mut F) -> Result<(), BlobWalkError>
+where
+    F: FnMut(i64) -> Result<String, BlobWalkError>,
+{
+    match value {
+        Value::Object(map) => {
+            if let Some(sentinel) = map.remove(SENTINEL_KEY) {
+                let local_id = sentinel.as_i64().ok_or(BlobWalkError::MalformedSentinel)?;
+                let target_jmap_id = resolve(local_id)?;
+                map.insert("blobId".to_owned(), Value::String(target_jmap_id));
+            }
+            for child in map.values_mut() {
+                walk_export(child, resolve)?;
+            }
+        }
+        Value::Array(items) => {
+            for item in items {
+                walk_export(item, resolve)?;
+            }
+        }
+        _ => {}
+    }
+    Ok(())
+}
+
+pub fn prepend_property(target: &mut Map<String, Value>, key: &str, value: Value) {
+    let existing: Vec<(String, Value)> =
+        target.iter().map(|(k, v)| (k.clone(), v.clone())).collect();
+    target.clear();
+    target.insert(key.to_owned(), value);
+    for (k, v) in existing {
+        if k != key {
+            target.insert(k, v);
+        }
+    }
+}
+
+#[derive(Debug, thiserror::Error)]
+pub enum BlobWalkError {
+    #[error("malformed @blob sentinel: expected integer local id")]
+    MalformedSentinel,
+    #[error("blob resolver failed: {0}")]
+    Resolver(String),
+}