ProjectExplorer: Implement (Docker)Device::exists(filePath)

While the original plan was to use more specific functions like
'isReadableFile' to cut down the number of accesses, it is
unrealistic to re-write all occurrences in reasonable time.
So make the basic building blocks accessible, too.

Change-Id: I2586ebd19e1e7ae2c884fd2a4180869421293e3a
Reviewed-by: David Schulz <david.schulz@qt.io>

src/libs/utils/fileutils.cpp

@@ -832,7 +832,10 @@ void FilePath::setHost(const QString &host)
 /// FilePath exists.
 bool FilePath::exists() const
 {
-    QTC_ASSERT(!needsDevice(), return false);
+    if (needsDevice()) {
+        QTC_ASSERT(s_deviceHooks.exists, return false);
+        return s_deviceHooks.exists(*this);
+    }
     return !isEmpty() && QFileInfo::exists(m_data);
 }
 

src/libs/utils/fileutils.h

@@ -75,6 +75,7 @@ public:
     std::function<bool(const FilePath &)> isWritableDir;
     std::function<bool(const FilePath &)> ensureWritableDir;
     std::function<bool(const FilePath &)> createDir;
+    std::function<bool(const FilePath &)> exists;
     std::function<QList<FilePath>(const FilePath &, const QStringList &, QDir::Filters)> dirEntries;
     std::function<QByteArray(const FilePath &, int)> fileContents;
 };

src/plugins/docker/dockerdevice.cpp

@@ -688,6 +688,22 @@ bool DockerDevice::createDirectory(const FilePath &filePath) const
     return exitCode == 0;
 }
 
+bool DockerDevice::exists(const FilePath &filePath) const
+{
+    QTC_ASSERT(handlesFile(filePath), return false);
+    tryCreateLocalFileAccess();
+    if (hasLocalFileAccess()) {
+        const FilePath localAccess = mapToLocalAccess(filePath);
+        const bool res = localAccess.exists();
+        LOG("Exists? " << filePath.toUserOutput() << localAccess.toUserOutput() << res);
+        return res;
+    }
+    const QString path = filePath.path();
+    const CommandLine cmd("test", {"-e", path});
+    const int exitCode = d->runSynchronously(cmd);
+    return exitCode == 0;
+}
+
 QList<FilePath> DockerDevice::directoryEntries(const FilePath &filePath,
                                                const QStringList &nameFilters,
                                                QDir::Filters filters) const

src/plugins/docker/dockerdevice.h

@@ -78,6 +78,7 @@ public:
     bool isReadableDirectory(const Utils::FilePath &filePath) const override;
     bool isWritableDirectory(const Utils::FilePath &filePath) const override;
     bool createDirectory(const Utils::FilePath &filePath) const override;
+    bool exists(const Utils::FilePath &filePath) const override;
     QList<Utils::FilePath> directoryEntries(const Utils::FilePath &filePath,
                                             const QStringList &nameFilters,
                                             QDir::Filters filters) const override;

src/plugins/projectexplorer/devicesupport/devicemanager.cpp

@@ -401,6 +401,12 @@ DeviceManager::DeviceManager(bool isInstance) : d(std::make_unique<DeviceManager
         return device->createDirectory(filePath);
     };
 
+    deviceHooks.exists = [](const FilePath &filePath) {
+        auto device = DeviceManager::deviceForPath(filePath);
+        QTC_ASSERT(device, return false);
+        return device->exists(filePath);
+    };
+
     deviceHooks.dirEntries = [](const FilePath &filePath,
             const QStringList &nameFilters, QDir::Filters filters) {
         auto device = DeviceManager::deviceForPath(filePath);

src/plugins/projectexplorer/devicesupport/idevice.cpp

@@ -259,6 +259,13 @@ bool IDevice::createDirectory(const Utils::FilePath &filePath) const
     return false;
 }
 
+bool IDevice::exists(const Utils::FilePath &filePath) const
+{
+    Q_UNUSED(filePath);
+    QTC_CHECK(false);
+    return false;
+}
+
 QList<FilePath> IDevice::directoryEntries(const FilePath &filePath,
                                           const QStringList &nameFilters,
                                           QDir::Filters filters) const

src/plugins/projectexplorer/devicesupport/idevice.h

@@ -242,6 +242,7 @@ public:
     virtual bool isWritableDirectory(const Utils::FilePath &filePath) const;
     virtual bool ensureWritableDirectory(const Utils::FilePath &filePath) const;
     virtual bool createDirectory(const Utils::FilePath &filePath) const;
+    virtual bool exists(const Utils::FilePath &filePath) const;
     virtual QList<Utils::FilePath> directoryEntries(const Utils::FilePath &filePath,
                                                     const QStringList &nameFilters,
                                                     QDir::Filters filters) const;