CompilationDatabase: Use QJsonDocument for separate objects

It is pretty easy to split objects without QJsonDocument help.

Due to the QJsonObject data size restriction use it
only for the already split objects inside the database.

Change-Id: Ice7c7407ad00aaac151a767f4d943fdcecf6a6b8
Reviewed-by: Orgad Shaneh <orgads@gmail.com>

src/plugins/compilationdatabaseprojectmanager/compilationdatabaseproject.cpp

@@ -302,26 +302,51 @@ void createFolders(FolderNode *root, const Utils::FileName &rootPath)
     }
 }
 
+std::vector<QJsonObject> readJsonObjects(const QString &filePath)
+{
+    std::vector<QJsonObject> result;
+    QFile file(filePath);
+    if (!file.open(QIODevice::ReadOnly))
+        return result;
+
+    const QByteArray contents = file.readAll();
+    int objectStart = contents.indexOf('{');
+    int objectEnd = contents.indexOf('}', objectStart + 1);
+
+    while (objectStart >= 0 && objectEnd >= 0) {
+        const QJsonDocument document = QJsonDocument::fromJson(
+                    contents.mid(objectStart, objectEnd - objectStart + 1));
+        if (document.isNull()) {
+            // The end was found incorrectly, search for the next one.
+            objectEnd = contents.indexOf('}', objectEnd + 1);
+            continue;
+        }
+
+        result.push_back(document.object());
+        objectStart = contents.indexOf('{', objectEnd + 1);
+        objectEnd = contents.indexOf('}', objectStart + 1);
+    }
+
+    return result;
+}
+
 } // anonymous namespace
 
 void CompilationDatabaseProject::buildTreeAndProjectParts(const Utils::FileName &projectFile)
 {
-    QFile file(projectFilePath().toString());
+    std::vector<QJsonObject> array = readJsonObjects(projectFilePath().toString());
-    if (!file.open(QIODevice::ReadOnly)) {
+    if (array.empty()) {
         emitParsingFinished(false);
         return;
     }
 
-    const QJsonArray array = QJsonDocument::fromJson(file.readAll()).array();
-
     auto root = std::make_unique<DBProjectNode>(projectDirectory());
 
     CppTools::RawProjectParts rpps;
     Utils::FileName commonPath;
     ToolChain *cToolchain = nullptr;
     ToolChain *cxxToolchain = nullptr;
-    for (const QJsonValue &element : array) {
+    for (const QJsonObject &object : array) {
-        const QJsonObject object = element.toObject();
         Utils::FileName fileName = jsonObjectFilename(object);
         const QStringList flags = jsonObjectFlags(object);