Add temporary file class

src/CMakeLists.txt

@@ -43,6 +43,7 @@ set(SOURCES
   core/localredirectserver.cpp
   core/mimedata.cpp
   core/potranslator.cpp
+  core/temporaryfile.cpp
   utilities/strutils.cpp
   utilities/envutils.cpp
   utilities/colorutils.cpp

src/core/temporaryfile.cpp

@@ -0,0 +1,73 @@
+/*
+ * Strawberry Music Player
+ * Copyright 2024, Jonas Kvinge <jonas@jkvinge.net>
+ *
+ * Strawberry is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * Strawberry is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with Strawberry.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#include <QString>
+#include <QFile>
+#include <QRandomGenerator>
+
+#include "core/logging.h"
+
+#include "temporaryfile.h"
+
+TemporaryFile::TemporaryFile(const QString &filename_pattern) {
+
+  int i = 0;
+  do {
+    filename_ = GenerateFilename(filename_pattern);
+    ++i;
+  } while (QFile::exists(filename_) && i < 100);
+
+  if (QFile::exists(filename_)) {
+    qLog(Error) << "Could not get a filename from pattern" << filename_pattern;
+    filename_.clear();
+  }
+  else {
+    qLog(Debug) << "Temporary file" << filename_ << "available";
+  }
+
+}
+
+TemporaryFile::~TemporaryFile() {
+
+  if (!filename_.isEmpty() && QFile::exists(filename_)) {
+    qLog(Debug) << "Deleting temporary file" << filename_;
+    if (!QFile::remove(filename_)) {
+      qLog(Debug) << "Could not delete temporary file" << filename_;
+    }
+  }
+
+}
+
+QString TemporaryFile::GenerateFilename(const QString &filename_pattern) const {
+
+  static const QString random_chars = QStringLiteral("abcdefghijklmnopqrstuvwxyz0123456789");
+
+  QString filename = filename_pattern;
+
+  Q_FOREVER {
+    const qint64 i = filename.indexOf(QLatin1Char('X'));
+    if (i == -1) break;
+    const qint64 index = QRandomGenerator::global()->bounded(0, random_chars.length());
+    const QChar random_char = random_chars.at(index);
+    filename[i] = random_char;
+  }
+
+  return filename;
+
+}

src/core/temporaryfile.h

@@ -0,0 +1,39 @@
+/*
+ * Strawberry Music Player
+ * Copyright 2024, Jonas Kvinge <jonas@jkvinge.net>
+ *
+ * Strawberry is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * Strawberry is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with Strawberry.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#ifndef TEMPORARYFILE_H
+#define TEMPORARYFILE_H
+
+#include <QString>
+
+class TemporaryFile {
+ public:
+  explicit TemporaryFile(const QString &filename_pattern);
+  ~TemporaryFile();
+
+  QString filename() const { return filename_; }
+
+ private:
+  QString GenerateFilename(const QString &filename_pattern) const;
+
+ private:
+  QString filename_;
+};
+
+#endif // TEMPORARYFILE_H

tests/src/utilities_test.cpp

@@ -24,6 +24,7 @@
 #include <QByteArray>
 #include <QString>
 #include <QDateTime>
+#include <QRegularExpression>
 #include <QtDebug>
 
 #include "test_utils.h"
@@ -35,6 +36,7 @@
 #include "utilities/colorutils.h"
 #include "utilities/transliterate.h"
 #include "core/logging.h"
+#include "core/temporaryfile.h"
 
 TEST(UtilitiesTest, PrettyTimeDelta) {
 
@@ -244,3 +246,19 @@ TEST(UtilitiesTest, ReplaceMessage) {
   ASSERT_EQ(Utilities::ReplaceMessage(QStringLiteral("%title% - %artist%"), song, QLatin1String("")), song.title() + QStringLiteral(" - ") + song.artist());
 
 }
+
+TEST(UtilitiesTest, TemporaryFile) {
+
+  QString filename_pattern = QStringLiteral("/tmp/test-XXXX.jpg");
+
+  TemporaryFile temp_file(filename_pattern);
+
+  EXPECT_FALSE(temp_file.filename().isEmpty());
+
+  EXPECT_FALSE(temp_file.filename() == filename_pattern);
+
+  static const QRegularExpression regex_temp_filename(QStringLiteral("^\\/tmp\\/test-....\\.jpg$"));
+
+  EXPECT_TRUE(regex_temp_filename.match(temp_file.filename()).hasMatch());
+
+}