Utils: Add FilePath::tmpDir and createTempFile

Change-Id: I6f3143e59a87edffeee5e08708ba721293a8a369
Reviewed-by: hjk <hjk@qt.io>

src/libs/utils/devicefileaccess.cpp

@@ -19,6 +19,8 @@
 #include <QOperatingSystemVersion>
 #include <QRegularExpression>
 #include <QStorageInfo>
+#include <QTemporaryFile>
+#include <QRandomGenerator>
 
 #ifdef Q_OS_WIN
 #ifdef QTCREATOR_PCH_H
@@ -30,6 +32,8 @@
 #include <qplatformdefs.h>
 #endif
 
+#include <algorithm>
+
 namespace Utils {
 
 // DeviceFileAccess
@@ -397,6 +401,15 @@ void DeviceFileAccess::asyncCopyFile(const FilePath &filePath,
     cont(copyFile(filePath, target));
 }
 
+expected_str<FilePath> DeviceFileAccess::createTempFile(const FilePath &filePath)
+{
+    Q_UNUSED(filePath)
+    QTC_CHECK(false);
+    return make_unexpected(Tr::tr("createTempFile is not implemented for \"%1\"")
+                               .arg(filePath.toUserOutput()));
+}
+
+
 // DesktopDeviceFileAccess
 
 DesktopDeviceFileAccess::~DesktopDeviceFileAccess() = default;
@@ -690,6 +703,16 @@ expected_str<qint64> DesktopDeviceFileAccess::writeFileContents(const FilePath &
     return res;
 }
 
+expected_str<FilePath> DesktopDeviceFileAccess::createTempFile(const FilePath &filePath)
+{
+    QTemporaryFile file(filePath.path());
+    file.setAutoRemove(false);
+    if (!file.open())
+        return make_unexpected(Tr::tr("Could not create temporary file in \"%1\" (%2)").arg(filePath.toUserOutput()).arg(file.errorString()));
+    return FilePath::fromString(file.fileName()).onDevice(filePath);
+}
+
+
 QDateTime DesktopDeviceFileAccess::lastModified(const FilePath &filePath) const
 {
     return QFileInfo(filePath.path()).lastModified();
@@ -965,6 +988,65 @@ expected_str<qint64> UnixDeviceFileAccess::writeFileContents(const FilePath &fil
     return data.size();
 }
 
+expected_str<FilePath> UnixDeviceFileAccess::createTempFile(const FilePath &filePath)
+{
+    if (!m_hasMkTemp.has_value())
+        m_hasMkTemp = runInShellSuccess({"which", {"mktemp"}, OsType::OsTypeLinux});
+
+    QString tmplate = filePath.path();
+    // Some mktemp implementations require a suffix of XXXXXX.
+    // They will only accept the template if at least the last 6 characters are X.
+    if (!tmplate.endsWith("XXXXXX"))
+        tmplate += ".XXXXXX";
+
+    if (m_hasMkTemp) {
+        const RunResult result = runInShell({"mktemp", {tmplate}, OsType::OsTypeLinux});
+
+        if (result.exitCode != 0) {
+            return make_unexpected(
+                Tr::tr("Failed creating temporary file \"%1\": %2")
+                    .arg(filePath.toUserOutput(), QString::fromUtf8(result.stdErr)));
+        }
+
+        return FilePath::fromString(QString::fromUtf8(result.stdOut.trimmed())).onDevice(filePath);
+    }
+
+    // Manually create a temporary/unique file.
+    std::reverse_iterator<QChar *> firstX = std::find_if_not(std::rbegin(tmplate),
+                                                             std::rend(tmplate),
+                                                             [](QChar ch) { return ch == 'X'; });
+
+    static constexpr std::array<QChar, 62> chars = {'0', '1', '2', '3', '4', '5', '6', '7', '8',
+                                                    '9', 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h',
+                                                    'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q',
+                                                    'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z',
+                                                    'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I',
+                                                    'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R',
+                                                    'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z'};
+
+    std::uniform_int_distribution<> dist(0, chars.size() - 1);
+
+    int maxTries = 10;
+    FilePath newPath;
+    do {
+        for (QChar *it = firstX.base(); it != std::end(tmplate); ++it) {
+            *it = chars[dist(*QRandomGenerator::global())];
+        }
+        newPath = FilePath::fromString(tmplate).onDevice(filePath);
+        if (--maxTries == 0) {
+            return make_unexpected(Tr::tr("Failed creating temporary file \"%1\" (too many tries)")
+                                       .arg(filePath.toUserOutput()));
+        }
+    } while (newPath.exists());
+
+    const expected_str<qint64> createResult = newPath.writeFileContents({});
+
+    if (!createResult)
+        return make_unexpected(createResult.error());
+
+    return newPath;
+}
+
 OsType UnixDeviceFileAccess::osType(const FilePath &filePath) const
 {
     Q_UNUSED(filePath)

src/libs/utils/devicefileaccess.h

@@ -81,6 +81,8 @@ protected:
     virtual void asyncCopyFile(const FilePath &filePath,
                                const Continuation<expected_str<void>> &cont,
                                const FilePath &target) const;
+
+    virtual expected_str<FilePath> createTempFile(const FilePath &filePath);
 };
 
 class QTCREATOR_UTILS_EXPORT DesktopDeviceFileAccess : public DeviceFileAccess
@@ -135,6 +137,9 @@ protected:
     expected_str<qint64> writeFileContents(const FilePath &filePath,
                                            const QByteArray &data,
                                            qint64 offset) const override;
+
+    expected_str<FilePath> createTempFile(const FilePath &filePath) override;
+
 };
 
 class QTCREATOR_UTILS_EXPORT UnixDeviceFileAccess : public DeviceFileAccess
@@ -186,6 +191,9 @@ protected:
                                            const QByteArray &data,
                                            qint64 offset) const override;
 
+    expected_str<FilePath> createTempFile(const FilePath &filePath) override;
+
+
 private:
     bool iterateWithFind(
             const FilePath &filePath,
@@ -197,6 +205,7 @@ private:
             QStringList *found) const;
 
     mutable bool m_tryUseFind = true;
+    mutable std::optional<bool> m_hasMkTemp;
 };
 
 } // Utils

src/libs/utils/filepath.cpp

@@ -20,6 +20,7 @@
 #include <QStringView>
 #include <QUrl>
 #include <QtGlobal>
+#include <QTemporaryFile>
 
 #ifdef Q_OS_WIN
 #ifdef QTCREATOR_PCH_H
@@ -490,6 +491,40 @@ std::optional<FilePath> FilePath::refersToExecutableFile(MatchScope matchScope)
     return fileAccess()->refersToExecutableFile(*this,  matchScope);
 }
 
+expected_str<FilePath> FilePath::tmpDir() const
+{
+    if (needsDevice()) {
+        const Environment env = deviceEnvironment();
+        if (env.hasKey("TMPDIR"))
+            return FilePath::fromUserInput(env.value("TMPDIR")).onDevice(*this);
+        if (env.hasKey("TEMP"))
+            return FilePath::fromUserInput(env.value("TEMP")).onDevice(*this);
+        if (env.hasKey("TMP"))
+            return FilePath::fromUserInput(env.value("TMP")).onDevice(*this);
+
+        if (osType() != OsTypeWindows)
+            return FilePath("/tmp").onDevice(*this);
+        return make_unexpected(QString("Could not find temporary directory on device %1")
+                               .arg(displayName()));
+    }
+
+    return FilePath::fromUserInput(QDir::tempPath());
+}
+
+expected_str<FilePath> FilePath::createTempFile() const
+{
+    if (!needsDevice()) {
+        QTemporaryFile file(toFSPathString());
+        file.setAutoRemove(false);
+        if (file.open())
+            return FilePath::fromString(file.fileName());
+
+        return make_unexpected(QString("Could not create temporary file: %1").arg(file.errorString()));
+    }
+
+    return fileAccess()->createTempFile(*this);
+}
+
 bool FilePath::isReadableFile() const
 {
     return fileAccess()->isReadableFile(*this);

src/libs/utils/filepath.h

@@ -184,6 +184,9 @@ public:
                       WithExeOrBatSuffix, WithAnySuffix };
     std::optional<FilePath> refersToExecutableFile(MatchScope considerScript) const;
 
+    [[nodiscard]] expected_str<FilePath> tmpDir() const;
+    [[nodiscard]] expected_str<FilePath> createTempFile() const;
+
     // makes sure that capitalization of directories is canonical
     // on Windows and macOS. This is rarely needed.
     [[nodiscard]] FilePath normalizedPathName() const;

tests/auto/utils/fileutils/tst_fileutils.cpp

@@ -115,6 +115,9 @@ private slots:
     void hostSpecialChars_data();
     void hostSpecialChars();
 
+    void tmp_data();
+    void tmp();
+
 private:
     QTemporaryDir tempDir;
     QString rootPath;
@@ -1325,6 +1328,36 @@ void tst_fileutils::hostSpecialChars()
     QCOMPARE(toFromExpected, expected);
 }
 
+void tst_fileutils::tmp_data()
+{
+    QTest::addColumn<QString>("templatepath");
+    QTest::addColumn<bool>("expected");
+
+    QTest::addRow("empty") << "" << true;
+    QTest::addRow("no-template") << "foo" << true;
+    QTest::addRow("realtive-template") << "my-file-XXXXXXXX" << true;
+    QTest::addRow("absolute-template") << QDir::tempPath() + "/my-file-XXXXXXXX" << true;
+    QTest::addRow("non-existing-dir") << "/this/path/does/not/exist/my-file-XXXXXXXX" << false;
+
+    QTest::addRow("on-device") << "device://test/./my-file-XXXXXXXX" << true;
+}
+
+void tst_fileutils::tmp()
+{
+    QFETCH(QString, templatepath);
+    QFETCH(bool, expected);
+
+    FilePath fp = FilePath::fromString(templatepath);
+
+    const auto result = fp.createTempFile();
+    QCOMPARE(result.has_value(), expected);
+
+    if (result.has_value()) {
+        QVERIFY(result->exists());
+        QVERIFY(result->removeFile());
+    }
+}
+
 QTEST_GUILESS_MAIN(tst_fileutils)
 
 #include "tst_fileutils.moc"