Docker: Implement DockerDevice::systemEnvironment() function

For synchronous retrieval of the system environment of the device.

Change-Id: I057f9591866b72e37733d495a2a6b203fae91ac4
Reviewed-by: Christian Kandeler <christian.kandeler@qt.io>

src/plugins/docker/dockerdevice.cpp

@@ -294,6 +294,8 @@ public:
     QList<ToolChain *> autoDetectToolChains();
     void autoDetectCMake();
 
+    void fetchSystemEnviroment();
+
     DockerDevice *q;
     DockerDeviceData m_data;
 
@@ -302,6 +304,8 @@ public:
     QString m_container;
     QString m_mergedDir;
     QFileSystemWatcher m_mergedDirWatcher;
+
+    Environment m_cachedEnviroment;
 };
 
 DockerDevice::DockerDevice(const DockerDeviceData &data)
@@ -730,6 +734,26 @@ void DockerDevice::runProcess(QtcProcess &process) const
     process.start();
 }
 
+Environment DockerDevice::systemEnvironment() const
+{
+    if (d->m_cachedEnviroment.size() == 0)
+        d->fetchSystemEnviroment();
+
+    QTC_CHECK(d->m_cachedEnviroment.size() != 0);
+    return d->m_cachedEnviroment;
+}
+
+void DockerDevicePrivate::fetchSystemEnviroment()
+{
+    SynchronousProcess proc;
+    proc.setCommand({"env", {}});
+
+    proc.runBlocking();
+
+    const QString remoteOutput = proc.stdOut();
+    m_cachedEnviroment = Environment(remoteOutput.split('\n', Qt::SkipEmptyParts), q->osType());
+}
+
 int DockerDevicePrivate::runSynchronously(const CommandLine &cmd) const
 {
     CommandLine dcmd{"docker", {"exec", m_container}};

src/plugins/docker/dockerdevice.h

@@ -84,6 +84,8 @@ public:
     QByteArray fileContents(const Utils::FilePath &filePath, int limit) const override;
     void runProcess(Utils::QtcProcess &process) const override;
 
+    Utils::Environment systemEnvironment() const override;
+
     const DockerDeviceData &data() const;
 
     void tryCreateLocalFileAccess() const;