Coordinate proxy decompilation and harden JDTLS response routing (#296)

- Move `jdt://` resolution to a bounded coordinator with request
deduplication, priorities, deadlines, cancellation, and negative
caching.
- Add session-isolated, atomically written decompiled-source caches with
valid filenames and encoded cross-platform file URIs.
- Serialize proxy output and safely route proxy-owned, late, suppressed,
and rewritten responses.
- Handle workspace-symbol supersession and proxy shutdown without
blocking transport threads.
- Improve completion snippet sanitization and refactor stdin/stdout
routing into testable handlers.

Author: tartarughina

Cargo.lock

@@ -14,6 +14,7 @@ path = "src/lib.rs"
 tokio = ["dep:tokio"]
 
 [dependencies]
+percent-encoding = "2.3"
 serde = { version = "1.0", features = ["derive"] }
 serde_json = "1.0"
 tokio = { version = "1", default-features = false, features = ["io-util"], optional = true }

proxy-common/Cargo.toml

@@ -1,21 +1,84 @@
+use percent_encoding::{utf8_percent_encode, AsciiSet, NON_ALPHANUMERIC};
 use std::path::Path;
 
-/// Convert a filesystem path to a `file://` URI, matching how language servers'
-/// `publishDiagnostics` and the editor key documents.
-///
-/// On Unix the path already starts with `/`, so `file://` + path gives the
-/// correct `file:///…` form with no extra work.
-///
-/// On Windows the backslashes are replaced with `/` and an extra `/` is
-/// prepended before the drive letter, so we get `file:///C:/…` rather than
-/// `file://C:\…`.
-#[cfg(unix)]
+const PATH_ENCODE_SET: AsciiSet = NON_ALPHANUMERIC
+    .remove(b'/')
+    .remove(b':')
+    .remove(b'-')
+    .remove(b'.')
+    .remove(b'_')
+    .remove(b'~')
+    .remove(b'@');
+
+/// Convert a filesystem path to an RFC 3986 percent-encoded `file://` URI.
 pub fn path_to_file_uri(path: &Path) -> String {
-    format!("file://{}", path.display())
+    file_uri_from_path_string(&path.to_string_lossy(), cfg!(windows))
 }
 
-#[cfg(windows)]
-pub fn path_to_file_uri(path: &Path) -> String {
-    let s = path.display().to_string().replace('\\', "/");
-    format!("file:///{s}")
+fn file_uri_from_path_string(path: &str, windows: bool) -> String {
+    let mut normalized = if windows {
+        path.replace('\\', "/")
+    } else {
+        path.to_string()
+    };
+    if windows {
+        if let Some(unc) = normalized.strip_prefix("//?/UNC/") {
+            normalized = format!("//{unc}");
+        } else if let Some(verbatim) = normalized.strip_prefix("//?/") {
+            normalized = verbatim.to_string();
+        }
+        if let Some(unc) = normalized.strip_prefix("//") {
+            return format!("file://{}", utf8_percent_encode(unc, &PATH_ENCODE_SET));
+        }
+    }
+    let prefix = if normalized.starts_with('/') {
+        "file://"
+    } else {
+        "file:///"
+    };
+    format!(
+        "{prefix}{}",
+        utf8_percent_encode(&normalized, &PATH_ENCODE_SET)
+    )
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn encodes_reserved_characters_in_unix_paths() {
+        assert_eq!(
+            file_uri_from_path_string("/tmp/Java Sources/#1%?.java", false),
+            "file:///tmp/Java%20Sources/%231%25%3F.java"
+        );
+    }
+
+    #[test]
+    fn normalizes_and_encodes_windows_paths() {
+        assert_eq!(
+            file_uri_from_path_string(r"C:\Users\Jane Doe\A#1.java", true),
+            "file:///C:/Users/Jane%20Doe/A%231.java"
+        );
+    }
+
+    #[test]
+    fn preserves_windows_unc_authority() {
+        assert_eq!(
+            file_uri_from_path_string(r"\\server\share\A File.java", true),
+            "file://server/share/A%20File.java"
+        );
+    }
+
+    #[test]
+    fn normalizes_windows_verbatim_paths() {
+        assert_eq!(
+            file_uri_from_path_string(r"\\?\C:\Users\Jane Doe\A.java", true),
+            "file:///C:/Users/Jane%20Doe/A.java"
+        );
+        assert_eq!(
+            file_uri_from_path_string(r"\\?\UNC\server\share\A.java", true),
+            "file://server/share/A.java"
+        );
+    }
 }

proxy-common/src/uri.rs

@@ -12,5 +12,7 @@ path = "src/main.rs"
 
 [dependencies]
 proxy-common.workspace = true
+hex = "0.4"
 serde = { version = "1.0", features = ["derive"] }
 serde_json = "1.0"
+sha1 = "0.10"

proxy/Cargo.toml

@@ -1,19 +1,15 @@
 use serde_json::Value;
 
-/// Returns true if the message contains a completion response with items.
-pub fn is_completion_response(msg: &Value) -> bool {
-    msg.get("result").is_some_and(|result| {
-        result.get("items").is_some_and(|v| v.is_array()) || result.is_array()
-    })
-}
-
 /// Single-pass processing of completion items:
 /// - Sorts methods/functions by parameter count (prepends count to sortText)
 /// - Strips unsupported VS Code snippet variables ($TM_SELECTED_TEXT) from snippets
 pub fn process_completions(msg: &mut Value) {
+    let default_insert_text_format = msg
+        .pointer("/result/itemDefaults/insertTextFormat")
+        .and_then(Value::as_u64);
     let items = match msg.get_mut("result") {
         Some(result) if result.is_array() => result.as_array_mut(),
-        Some(result) => result.get_mut("items").and_then(|v| v.as_array_mut()),
+        Some(result) => result.get_mut("items").and_then(Value::as_array_mut),
         None => None,
     };
 
@@ -33,20 +29,29 @@ pub fn process_completions(msg: &mut Value) {
                 let existing = item.get("sortText").and_then(|v| v.as_str()).unwrap_or("");
                 item["sortText"] = Value::String(format!("{count:02}{existing}"));
             }
-            // Snippet (15): strip $TM_SELECTED_TEXT
-            15 => {
-                strip_tm_selected_text(item, "textEditText");
-                strip_tm_selected_text(item, "insertText");
-            }
             _ => {}
         }
+
+        let insert_text_format = item
+            .get("insertTextFormat")
+            .and_then(Value::as_u64)
+            .or(default_insert_text_format);
+        if kind == 15 || insert_text_format == Some(2) {
+            sanitize_completion_item(item);
+        }
     }
 }
 
-fn strip_tm_selected_text(item: &mut Value, key: &str) {
-    if let Some(text) = item.get(key).and_then(|v| v.as_str()) {
+fn sanitize_completion_item(item: &mut Value) {
+    strip_tm_selected_text(item, "/textEditText");
+    strip_tm_selected_text(item, "/insertText");
+    strip_tm_selected_text(item, "/textEdit/newText");
+}
+
+fn strip_tm_selected_text(item: &mut Value, pointer: &str) {
+    if let Some(Value::String(text)) = item.pointer_mut(pointer) {
         if text.contains("$TM_SELECTED_TEXT") {
-            item[key] = Value::String(text.replace("$TM_SELECTED_TEXT", ""));
+            *text = text.replace("$TM_SELECTED_TEXT", "");
         }
     }
 }
@@ -56,15 +61,7 @@ pub fn sanitize_resolved_completion(msg: &mut Value) {
     let Some(result) = msg.get_mut("result") else {
         return;
     };
-    strip_tm_selected_text(result, "textEditText");
-    strip_tm_selected_text(result, "insertText");
-    // Also check inside textEdit.newText
-    if let Some(new_text) = result.pointer("/textEdit/newText").and_then(|v| v.as_str()) {
-        if new_text.contains("$TM_SELECTED_TEXT") {
-            result["textEdit"]["newText"] =
-                Value::String(new_text.replace("$TM_SELECTED_TEXT", ""));
-        }
-    }
+    sanitize_completion_item(result);
 }
 
 fn count_params(detail: &str) -> usize {
@@ -87,3 +84,133 @@ fn count_params(detail: &str) -> usize {
     }
     count
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use serde_json::json;
+
+    #[test]
+    fn processes_array_completion_results() {
+        let mut response = json!({
+            "result": [{
+                "kind": 2,
+                "labelDetails": { "detail": "(String, List<String>)" },
+                "sortText": "method"
+            }]
+        });
+
+        process_completions(&mut response);
+
+        assert_eq!(response["result"][0]["sortText"], json!("02method"));
+    }
+
+    #[test]
+    fn applies_list_item_default_snippet_format() {
+        let mut response = json!({
+            "result": {
+                "itemDefaults": { "insertTextFormat": 2 },
+                "items": [{
+                    "kind": 2,
+                    "insertText": "$TM_SELECTED_TEXT.trim()"
+                }]
+            }
+        });
+
+        process_completions(&mut response);
+
+        assert_eq!(
+            response["result"]["items"][0]["insertText"],
+            json!(".trim()")
+        );
+    }
+
+    #[test]
+    fn sanitizes_text_edit_text() {
+        let mut response = json!({
+            "result": [{
+                "kind": 15,
+                "textEditText": "$TM_SELECTED_TEXT.field"
+            }]
+        });
+
+        process_completions(&mut response);
+
+        assert_eq!(response["result"][0]["textEditText"], json!(".field"));
+    }
+
+    #[test]
+    fn sanitizes_insert_replace_edit_text() {
+        let mut response = json!({
+            "result": [{
+                "kind": 15,
+                "textEdit": {
+                    "newText": "$TM_SELECTED_TEXT.var",
+                    "insert": {
+                        "start": { "line": 0, "character": 0 },
+                        "end": { "line": 0, "character": 0 }
+                    },
+                    "replace": {
+                        "start": { "line": 0, "character": 0 },
+                        "end": { "line": 0, "character": 3 }
+                    }
+                }
+            }]
+        });
+
+        process_completions(&mut response);
+
+        assert_eq!(response["result"][0]["textEdit"]["newText"], json!(".var"));
+    }
+
+    #[test]
+    fn leaves_plain_text_completion_unchanged() {
+        let mut response = json!({
+            "result": [{
+                "kind": 1,
+                "insertTextFormat": 1,
+                "insertText": "$TM_SELECTED_TEXT"
+            }]
+        });
+
+        process_completions(&mut response);
+
+        assert_eq!(
+            response["result"][0]["insertText"],
+            json!("$TM_SELECTED_TEXT")
+        );
+    }
+
+    #[test]
+    fn postfix_var_completion_keeps_jdtls_spacing() {
+        let insertion = "var name = \"hello world\";";
+        let mut response = json!({
+            "result": [{
+                "label": ".var",
+                "kind": 15,
+                "insertTextFormat": 2,
+                "textEdit": {
+                    "newText": insertion,
+                    "range": {
+                        "start": { "line": 0, "character": 0 },
+                        "end": { "line": 0, "character": 17 }
+                    }
+                }
+            }]
+        });
+
+        process_completions(&mut response);
+
+        assert_eq!(
+            response["result"][0]["textEdit"]["newText"],
+            json!(insertion)
+        );
+    }
+
+    #[test]
+    fn counts_nested_generic_parameters() {
+        assert_eq!(count_params("(Map<String, List<Integer>>, int)"), 2);
+        assert_eq!(count_params("()"), 0);
+        assert_eq!(count_params("not-a-signature"), 0);
+    }
+}