From f71bc5ad9ea580261a85a2bdbffa83090f3c57a1 Mon Sep 17 00:00:00 2001 From: Anton Kudryavtsev Date: Mon, 1 Feb 2016 10:42:04 +0300 Subject: [PATCH] qmake: optimize container usage in the json handling Iterate only once over QJsonObject, create key list by existing loop instead of create by QJsonObject::keys(), which contains internal loop. In common case if loop's statement is lightweight, then effect of optimization is significant, and vice versa. Also make addJsonArray() and addJsonObject() functions more homogeneous. Use reserve to optimize memory allocation. Change-Id: Id122cd1becfd34bb06640876b1c79e1d396d2a6b Reviewed-by: Oswald Buddenhagen (cherry picked from qtbase/69ab28031549ff1c9ceecdcb29197900e9bc4328) Reviewed-by: Jake Petroules Reviewed-by: Anton Kudryavtsev --- src/shared/proparser/qmakebuiltins.cpp | 16 +++++++++++----- 1 file changed, 11 insertions(+), 5 deletions(-) diff --git a/src/shared/proparser/qmakebuiltins.cpp b/src/shared/proparser/qmakebuiltins.cpp index 035a18493aa..203597aed44 100644 --- a/src/shared/proparser/qmakebuiltins.cpp +++ b/src/shared/proparser/qmakebuiltins.cpp @@ -296,7 +296,9 @@ static void insertJsonKeyValue(const QString &key, const QStringList &values, Pr static void addJsonArray(const QJsonArray &array, const QString &keyPrefix, ProValueMap *map) { QStringList keys; - for (int i = 0; i < array.count(); ++i) { + const int size = array.count(); + keys.reserve(size); + for (int i = 0; i < size; ++i) { keys.append(QString::number(i)); addJsonValue(array.at(i), keyPrefix + QString::number(i), map); } @@ -305,10 +307,14 @@ static void addJsonArray(const QJsonArray &array, const QString &keyPrefix, ProV static void addJsonObject(const QJsonObject &object, const QString &keyPrefix, ProValueMap *map) { - for (auto it = object.begin(), end = object.end(); it != end; ++it) - addJsonValue(it.value(), keyPrefix + it.key(), map); - - insertJsonKeyValue(keyPrefix + QLatin1String("_KEYS_"), object.keys(), map); + QStringList keys; + keys.reserve(object.size()); + for (auto it = object.begin(), end = object.end(); it != end; ++it) { + const QString key = it.key(); + keys.append(key); + addJsonValue(it.value(), keyPrefix + key, map); + } + insertJsonKeyValue(keyPrefix + QLatin1String("_KEYS_"), keys, map); } static void addJsonValue(const QJsonValue &value, const QString &keyPrefix, ProValueMap *map)