From d34f78b435768f571227ae43cb779f1c42c043fd Mon Sep 17 00:00:00 2001
From: Tristan Penman <tristan@tristanpenman.com>
Date: Sun, 6 Feb 2022 20:14:37 +1100
Subject: [PATCH] Improve error messaging when parsing schemas and documents

---
 inspector/src/window.cpp | 75 ++++++++++++++++++++++------------------
 inspector/src/window.h   |  6 ++--
 2 files changed, 44 insertions(+), 37 deletions(-)

diff --git a/inspector/src/window.cpp b/inspector/src/window.cpp
index 9d649ac..ac3fb0a 100644
--- a/inspector/src/window.cpp
+++ b/inspector/src/window.cpp
@@ -47,8 +47,10 @@ Window::Window(QWidget * parent)
     setCentralWidget(verticalSplitter);
     setStatusBar(statusBar);
 
-    connect(m_documentEditor, SIGNAL(textChanged()), this, SLOT(refreshDocumentJson()));
-    connect(m_schemaEditor, SIGNAL(textChanged()), this, SLOT(refreshSchemaJson()));
+    connect(m_documentEditor, SIGNAL(textChanged()), this, SLOT(refreshJson()));
+    connect(m_schemaEditor, SIGNAL(textChanged()), this, SLOT(refreshJson()));
+
+    refreshJson();
 }
 
 QTextEdit * Window::createEditor(bool readOnly)
@@ -114,50 +116,55 @@ QToolBar * Window::createToolBar()
     return toolbar;
 }
 
-void Window::refreshDocumentJson()
+void Window::refreshJson()
 {
-    const auto doc = m_documentEditor->toPlainText().toUtf8();
-    if (doc.isEmpty()) {
-        m_errors->setText("");
-        return;
-    }
+    QString errors;
+    m_errors->setText("");
 
-    QJsonParseError error;
-    m_document = QJsonDocument::fromJson(doc, &error);
-    if (m_document.isNull()) {
-        m_errors->setText(QString("Document error: ") + error.errorString());
-        return;
-    }
-
-    if (m_schema) {
-        validate();
-    } else {
-        m_errors->setText("");
-    }
-}
-
-void Window::refreshSchemaJson()
-{
     const auto schema = m_schemaEditor->toPlainText().toUtf8();
+    const auto doc = m_documentEditor->toPlainText().toUtf8();
+
     if (schema.isEmpty()) {
-        m_errors->setText("");
-        return;
+        if (doc.isEmpty()) {
+            m_errors->setText(
+              "Please provide a schema and a document to be validated.\n\n"
+              "Note that this example uses QtJson, which does not consider non-array and "
+              "non-object values to be valid JSON documents.");
+            return;
+        } else {
+            errors += "Schema error: must not be empty\n\n";
+        }
+    } else {
+        QJsonParseError error;
+        m_schemaJson = QJsonDocument::fromJson(schema, &error);
+        if (m_schemaJson.isNull()) {
+            errors += QString("Schema error: ") + error.errorString() + "\n\n";
+        }
     }
 
-    QJsonParseError error;
-    auto schemaDoc = QJsonDocument::fromJson(m_schemaEditor->toPlainText().toUtf8(), &error);
-    if (schemaDoc.isNull()) {
-        m_errors->setText(QString("Schema error: ") + error.errorString());
-        return;
+    if (doc.isEmpty()) {
+        if (!schema.isEmpty()) {
+            errors += "Document error: must not be empty\n\n";
+        }
+    } else {
+        QJsonParseError error;
+        m_documentJson = QJsonDocument::fromJson(doc, &error);
+        if (m_documentJson.isNull()) {
+            errors += QString("Document error: ") + error.errorString() + "\n\n";
+        }
+    }
+
+    if (!errors.isEmpty()) {
+      m_errors->setText(errors);
+      return;
     }
 
     try {
-        valijson::adapters::QtJsonAdapter adapter(schemaDoc.object());
+        valijson::adapters::QtJsonAdapter adapter(m_schemaJson.object());
         valijson::SchemaParser parser;
         delete m_schema;
         m_schema = new valijson::Schema();
         parser.populateSchema(adapter, *m_schema);
-        m_errors->setText("");
         validate();
     } catch (std::runtime_error & error) {
         delete m_schema;
@@ -190,7 +197,7 @@ void Window::validate()
 {
     valijson::ValidationResults results;
     valijson::Validator validator;
-    valijson::adapters::QtJsonAdapter adapter(m_document.object());
+    valijson::adapters::QtJsonAdapter adapter(m_documentJson.object());
 
     if (validator.validate(*m_schema, adapter, &results)) {
         m_errors->setText("Document is valid.");
diff --git a/inspector/src/window.h b/inspector/src/window.h
index 0e71628..a7fe516 100644
--- a/inspector/src/window.h
+++ b/inspector/src/window.h
@@ -22,8 +22,7 @@ public:
     explicit Window(QWidget * parent = 0);
 
 public slots:
-    void refreshDocumentJson();
-    void refreshSchemaJson();
+    void refreshJson();
 
     void showOpenDocumentDialog();
     void showOpenSchemaDialog();
@@ -42,7 +41,8 @@ private:
 
     QTextEdit * m_errors;
 
-    QJsonDocument m_document;
+    QJsonDocument m_documentJson;
+    QJsonDocument m_schemaJson;
 
     valijson::Schema * m_schema;
 };