nixd: support path completion

nixd/lib/Controller/Completion.cpp

@@ -12,6 +12,8 @@
 
 #include <boost/asio/post.hpp>
 
+#include <llvm/Support/FileSystem.h>
+#include <llvm/Support/Path.h>
 #include <semaphore>
 #include <set>
 #include <utility>
@@ -250,6 +252,43 @@ class OptionCompletionProvider {
   }
 };
 
+void completeExprPath(const std::string &CurFilePath,
+                      const nixf::ExprPath &ExprPath,
+                      std::vector<CompletionItem> &Items) {
+  using namespace llvm::sys;
+
+  if (!ExprPath.parts().isLiteral()) {
+    return;
+  }
+
+  const auto &PathLiteral = ExprPath.parts().literal();
+  if (PathLiteral.empty()) {
+    return;
+  }
+
+  llvm::SmallVector<char, 32> Path{PathLiteral.begin(), PathLiteral.end()};
+  if (PathLiteral[0] == '.') {
+    const auto &CurFileDir = path::parent_path(CurFilePath);
+    fs::make_absolute(CurFileDir, Path);
+  }
+
+  if (fs::exists(Path) && fs::is_directory(Path)) {
+    std::error_code EC;
+    for (auto Iter = fs::directory_iterator(Path, EC, false);
+         Iter != fs::directory_iterator(); Iter.increment(EC)) {
+      if (EC) {
+        vlog("failed to read directory: {0}", EC.message());
+        break;
+      }
+      addItem(Items, CompletionItem{
+                         .label = path::filename(Iter->path()).str(),
+                         .kind = CompletionItemKind::File,
+                         .data = ExprPath.parts().literal(),
+                     });
+    }
+  }
+}
+
 void completeAttrName(const std::vector<std::string> &Scope,
                       const std::string &Prefix,
                       Controller::OptionMapTy &Options, bool CompletionSnippets,
@@ -285,11 +324,12 @@ void Controller::onCompletion(const CompletionParams &Params,
         }
         CompletionList List;
         try {
+          bool FinishedCompletion = false;
           const ParentMapAnalysis &PM = *TU->parentMap();
+
+          // if we are in an attribute path, use AttrCompletionProvider only
           std::vector<std::string> Scope;
-          using PathResult = FindAttrPathResult;
-          auto R = findAttrPath(*Desc, PM, Scope);
-          if (R == PathResult::OK) {
+          if (findAttrPath(*Desc, PM, Scope) == FindAttrPathResult::OK) {
             // Construct request.
             std::string Prefix = Scope.back();
             Scope.pop_back();
@@ -298,7 +338,23 @@ void Controller::onCompletion(const CompletionParams &Params,
               completeAttrName(Scope, Prefix, Options,
                                ClientCaps.CompletionSnippets, List.items);
             }
-          } else {
+            FinishedCompletion = true;
+          }
+
+          // if we are in a literal path, use PathCompletionProvider only
+          if (!FinishedCompletion) {
+            const auto *Parent = PM.upExpr(*Desc);
+            if (Parent->kind() == Node::NK_ExprPath) {
+              const auto &Path = static_cast<const nixf::ExprPath &>(*Parent);
+              if (Path.parts().isLiteral()) {
+                completeExprPath(File, Path, List.items);
+                FinishedCompletion = true;
+              }
+            }
+          }
+
+          // otherwise, fallback to VLACompletionProvider
+          if (!FinishedCompletion) {
             const VariableLookupAnalysis &VLA = *TU->variableLookup();
             VLACompletionProvider VLAP(VLA);
             VLAP.complete(*Desc, List.items, PM);

nixd/tools/nixd/test/completion-path.md

@@ -0,0 +1,85 @@
+# RUN: sed "s|ROOT|%S|g" < %s | nixd --lit-test | FileCheck %s
+
+<-- initialize(0)
+
+```json
+{
+   "jsonrpc":"2.0",
+   "id":0,
+   "method":"initialize",
+   "params":{
+      "processId":123,
+      "rootPath":"",
+      "capabilities": {
+      },
+      "trace":"off"
+   }
+}
+```
+
+
+<-- textDocument/didOpen
+
+
+```json
+{
+   "jsonrpc":"2.0",
+   "method":"textDocument/didOpen",
+   "params":{
+      "textDocument":{
+         "uri":"file://ROOT/completion-path-root/main.nix",
+         "languageId":"nix",
+         "version":1,
+         "text":"{ bar = ./ }"
+      }
+   }
+}
+```
+
+```json
+{
+    "jsonrpc": "2.0",
+    "id": 1,
+    "method": "textDocument/completion",
+    "params": {
+        "textDocument": {
+            "uri": "file://ROOT/completion-path-root/main.nix"
+        },
+        "position": {
+            "line": 0,
+            "character": 9
+        },
+        "context": {
+            "triggerKind": 1,
+            "triggerCharacter": "/"
+        }
+    }
+}
+```
+
+```
+     CHECK:  "id": 1,
+CHECK-NEXT:  "jsonrpc": "2.0",
+CHECK-NEXT:  "result": {
+CHECK-NEXT:    "isIncomplete": false,
+CHECK-NEXT:    "items": [
+CHECK-NEXT:      {
+CHECK-NEXT:        "data": "./",
+CHECK-NEXT:        "kind": 17,
+CHECK-NEXT:        "label": "foo",
+CHECK-NEXT:        "score": 0
+CHECK-NEXT:      },
+CHECK-NEXT:      {
+CHECK-NEXT:        "data": "./",
+CHECK-NEXT:        "kind": 17,
+CHECK-NEXT:        "label": "main.nix",
+CHECK-NEXT:        "score": 0
+CHECK-NEXT:      }
+CHECK-NEXT:    ]
+CHECK-NEXT:  }
+```
+
+
+```json
+{"jsonrpc":"2.0","method":"exit"}
+```