Add manual template for git_commit_extract_signature

This is to date the only known (by the nodegit team) use case of a double return type from libgit2. If we spot other use cases for this, we will need to revisit this decision and build in the correct templating mechanism.

generate/input/descriptor.json

@@ -523,7 +523,7 @@
           "ignore": true
         },
         "git_commit_extract_signature": {
-          "ignore": true
+          "isAsync": true
         },
         "git_commit_id": {
           "return": {

generate/input/libgit2-supplement.json

@@ -86,6 +86,40 @@
   },
   "new" : {
     "functions": {
+      "git_commit_extract_signature": {
+        "args": [
+          {
+            "name": "signature",
+            "type": "git_buf"
+          },
+          {
+            "name": "signed_data",
+            "type": "git_buf"
+          },
+          {
+            "name": "repo",
+            "type": "git_repository *"
+          },
+          {
+            "name": "commit_id",
+            "type": "git_oid *"
+          },
+          {
+            "name": "field",
+            "type": "char *"
+          }
+        ],
+        "type": "function",
+        "isManual": true,
+        "cFile": "generate/templates/manual/commit/extract_signature.cc",
+        "isAsync": true,
+        "isPrototypeMethod": false,
+        "group": "commit",
+        "return": {
+          "type": "int",
+          "isErrorCode": true
+        }
+      },
       "git_patch_convenient_from_diff": {
         "args": [
           {

generate/templates/manual/commit/extract_signature.cc

@@ -0,0 +1,156 @@
+NAN_METHOD(GitCommit::ExtractSignature)
+{
+  if (info.Length() == 0 || !info[0]->IsObject()) {
+    return Nan::ThrowError("Repository repo is required.");
+  }
+
+  if (info.Length() == 1 || (!info[1]->IsObject() && !info[1]->IsString())) {
+    return Nan::ThrowError("Oid commit_id is required.");
+  }
+
+  if (info.Length() == 2 || (info.Length() == 3 && !info[2]->IsFunction())) {
+    return Nan::ThrowError("Callback is required and must be a Function.");
+  }
+
+  if (info.Length() >= 4) {
+    if (!info[2]->IsString() && !info[2]->IsUndefined() && !info[2]->IsNull()) {
+      return Nan::ThrowError("String signature_field must be a string or undefined/null.");
+    }
+
+    if (!info[3]->IsFunction()) {
+      return Nan::ThrowError("Callback is required and must be a Function.");
+    }
+  }
+
+  ExtractSignatureBaton* baton = new ExtractSignatureBaton;
+
+  baton->error_code = GIT_OK;
+  baton->error = NULL;
+  baton->signature = GIT_BUF_INIT_CONST(NULL, 0);
+  baton->signed_data = GIT_BUF_INIT_CONST(NULL, 0);
+  baton->repo = Nan::ObjectWrap::Unwrap<GitRepository>(info[0]->ToObject())->GetValue();
+
+  // baton->commit_id
+  if (info[1]->IsString()) {
+    String::Utf8Value oidString(info[1]->ToString());
+    baton->commit_id = (git_oid *)malloc(sizeof(git_oid));
+    if (git_oid_fromstr(baton->commit_id, (const char *)strdup(*oidString)) != GIT_OK) {
+      free(baton->commit_id);
+
+      if (giterr_last()) {
+        return Nan::ThrowError(giterr_last()->message);
+      } else {
+        return Nan::ThrowError("Unknown Error");
+      }
+    }
+  } else {
+    baton->commit_id = Nan::ObjectWrap::Unwrap<GitOid>(info[1]->ToObject())->GetValue();
+  }
+
+  // baton->field
+  if (info[2]->IsString()) {
+    String::Utf8Value field(info[2]->ToString());
+    baton->field = (char *)malloc(field.length() + 1);
+    memcpy((void *)baton->field, *field, field.length());
+    baton->field[field.length()] = 0;
+  } else {
+    baton->field = NULL;
+  }
+
+  Nan::Callback *callback;
+  if (info[2]->IsFunction()) {
+    callback = new Nan::Callback(Local<Function>::Cast(info[2]));
+  } else {
+    callback = new Nan::Callback(Local<Function>::Cast(info[3]));
+  }
+
+  ExtractSignatureWorker *worker = new ExtractSignatureWorker(baton, callback);
+  worker->SaveToPersistent("repo", info[0]->ToObject());
+  worker->SaveToPersistent("commit_id", info[1]->ToObject());
+  Nan::AsyncQueueWorker(worker);
+  return;
+}
+
+void GitCommit::ExtractSignatureWorker::Execute()
+{
+  giterr_clear();
+
+  {
+    LockMaster lockMaster(
+      /*asyncAction: */true,
+      baton->repo
+    );
+
+    baton->error_code = git_commit_extract_signature(
+      &baton->signature,
+      &baton->signed_data,
+      baton->repo,
+      baton->commit_id,
+      (const char *)baton->field
+    );
+
+    if (baton->error_code != GIT_OK && giterr_last() != NULL) {
+      baton->error = git_error_dup(giterr_last());
+    }
+  }
+}
+
+void GitCommit::ExtractSignatureWorker::HandleOKCallback()
+{
+  if (baton->error_code == GIT_OK)
+  {
+    Local<v8::Object> result = Nan::New<Object>();
+    Nan::Set(
+      result,
+      Nan::New("signature").ToLocalChecked(),
+      Nan::New<String>(baton->signature.ptr, baton->signature.size).ToLocalChecked()
+    );
+    Nan::Set(
+      result,
+      Nan::New("signedData").ToLocalChecked(),
+      Nan::New<String>(baton->signed_data.ptr, baton->signed_data.size).ToLocalChecked()
+    );
+
+    Local<v8::Value> argv[2] = {
+      Nan::Null(),
+      result
+    };
+    callback->Call(2, argv);
+  }
+  else if (baton->error)
+  {
+    Local<v8::Value> argv[1] = {
+      Nan::Error(baton->error->message)
+    };
+    callback->Call(1, argv);
+    if (baton->error->message)
+    {
+      free((void *)baton->error->message);
+    }
+
+    free((void *)baton->error);
+  }
+  else if (baton->error_code < 0)
+  {
+    Local<v8::Object> err = Nan::Error("Extract Signature has thrown an error.")->ToObject();
+    err->Set(Nan::New("errno").ToLocalChecked(), Nan::New(baton->error_code));
+    err->Set(Nan::New("errorFunction").ToLocalChecked(), Nan::New("Commit.extractSignature").ToLocalChecked());
+    Local<v8::Value> argv[1] = {
+      err
+    };
+    callback->Call(1, argv);
+  }
+  else
+  {
+    callback->Call(0, NULL);
+  }
+
+  git_buf_free(&baton->signature);
+  git_buf_free(&baton->signed_data);
+
+  if (baton->field != NULL) {
+    free((void *)baton->field);
+  }
+
+  delete baton;
+}