log_files: add blocking download_file; add erase log file function

examples/logfile_download/CMakeLists.txt

@@ -0,0 +1,23 @@
+cmake_minimum_required(VERSION 3.10.2)
+
+set(CMAKE_CXX_STANDARD 17)
+set(CMAKE_CXX_STANDARD_REQUIRED ON)
+
+project(logfile_download)
+
+add_executable(logfile_download
+    logfile_download.cpp
+)
+
+find_package(MAVSDK REQUIRED)
+
+target_link_libraries(logfile_download
+    MAVSDK::mavsdk_log_files
+    MAVSDK::mavsdk
+)
+
+if(NOT MSVC)
+    add_compile_options(logfile_download PRIVATE -Wall -Wextra)
+else()
+    add_compile_options(logfile_download PRIVATE -WX -W2)
+endif()

examples/logfile_download/logfile_download.cpp

@@ -0,0 +1,122 @@
+//
+// Example how to download logfiles with MAVSDK.
+//
+
+#include <mavsdk/mavsdk.h>
+#include <mavsdk/plugins/log_files/log_files.h>
+
+#include <chrono>
+#include <functional>
+#include <future>
+#include <iostream>
+#include <iomanip>
+#include <cstring>
+#include <thread>
+
+using namespace mavsdk;
+using std::chrono::seconds;
+using std::this_thread::sleep_for;
+
+void usage(const std::string& bin_name)
+{
+    std::cerr << "Usage : " << bin_name << " <connection_url> [--rm]\n"
+              << '\n'
+              << "Connection URL format should be :\n"
+              << " For TCP : tcp://[server_host][:server_port]\n"
+              << " For UDP : udp://[bind_host][:bind_port]\n"
+              << " For Serial : serial:///path/to/serial/dev[:baudrate]\n"
+              << "For example, to connect to the simulator use URL: udp://:14540\n"
+              << '\n'
+              << "To remove log files after all downloads completed,\n"
+              << "please add the --rm argument" << std::endl;
+}
+
+std::shared_ptr<System> get_system(Mavsdk& mavsdk)
+{
+    std::cerr << "Waiting to discover system...\n";
+    auto prom = std::promise<std::shared_ptr<System>>{};
+    auto fut = prom.get_future();
+
+    // We wait for new systems to be discovered, once we find one that has an
+    // autopilot, we decide to use it.
+    mavsdk.subscribe_on_new_system([&mavsdk, &prom]() {
+        auto system = mavsdk.systems().back();
+
+        // Unsubscribe again as we only want to find one system.
+        mavsdk.subscribe_on_new_system(nullptr);
+        prom.set_value(system);
+    });
+
+    // We usually receive heartbeats at 1Hz, therefore we should find a
+    // system after around 3 seconds max, surely.
+    if (fut.wait_for(seconds(3)) == std::future_status::timeout) {
+        std::cerr << "No autopilot found.\n";
+        return {};
+    }
+
+    // Get discovered system now.
+    return fut.get();
+}
+
+int main(int argc, char** argv)
+{
+    if (argc > 3) {
+        usage(argv[0]);
+        return 1;
+    }
+
+    /* parse arguments */
+    bool remove_log_files = false;
+
+    for (int i = 2; i < argc; ++i) {
+        if (argv[i] == "--rm") {
+            remove_log_files = true;
+        }
+    }
+
+    Mavsdk mavsdk;
+    ConnectionResult connection_result = mavsdk.add_any_connection(argv[1]);
+
+    if (connection_result != ConnectionResult::Success) {
+        std::cerr << "Connection failed: " << connection_result << std::endl;
+        return 1;
+    }
+
+    auto system = get_system(mavsdk);
+    if (!system) {
+        return 1;
+    }
+
+    // Instantiate plugins.
+
+    auto log_files = LogFiles{system};
+
+    auto get_entries_result = log_files.get_entries();
+    if (get_entries_result.first == LogFiles::Result::Success) {
+        bool download_failure = false;
+        for (auto entry : get_entries_result.second) {
+            std::cerr << "Got log file with ID " << entry.id << " and date " << entry.date
+                      << std::endl;
+            LogFiles::Result result =
+                log_files.download_log_file(entry, std::string("log-") + entry.date + ".ulg");
+            if (result != LogFiles::Result::Success) {
+                download_failure = true;
+                std::cerr << "LogFiles::download_log_file failed: " << result << std::endl;
+            }
+        }
+        if (!download_failure && remove_log_files) {
+            /*
+             * If you want to be sure the log has been deleted, call get_entries again
+             * that there are no log files present anymore
+             *
+             * TODO: provide a more reliable solution
+             */
+            log_files.erase_log_files();
+        }
+    } else {
+        std::cerr << "LogFiles::get_entries failed: " << get_entries_result.first << std::endl;
+        return 1;
+    }
+
+    return 0;
+}

src/mavsdk/plugins/log_files/include/plugins/log_files/log_files.h

@@ -160,6 +160,25 @@ class LogFiles : public PluginBase {
      */
     void download_log_file_async(Entry entry, std::string path, DownloadLogFileCallback callback);
 
+    /**
+     * @brief Download log file synchronously.
+     *
+     * This function is blocking.
+     *
+     * @return Result of request.
+     */
+    std::pair<Result, LogFiles::ProgressData>
+    download_log_file(Entry entry, std::string path) const;
+
+    /**
+     * @brief Erase all log files.
+     *
+     * This function is blocking.
+     *
+     * @return Result of request.
+     */
+    Result erase_all_log_files() const;
+
     /**
      * @brief Copy constructor.
      */

src/mavsdk/plugins/log_files/log_files.cpp

@@ -37,6 +37,17 @@ void LogFiles::download_log_file_async(
     _impl->download_log_file_async(entry, path, callback);
 }
 
+std::pair<LogFiles::Result, LogFiles::ProgressData>
+LogFiles::download_log_file(Entry entry, std::string path) const
+{
+    return _impl->download_log_file(entry, path);
+}
+
+LogFiles::Result LogFiles::erase_all_log_files() const
+{
+    return _impl->erase_all_log_files();
+}
+
 bool operator==(const LogFiles::ProgressData& lhs, const LogFiles::ProgressData& rhs)
 {
     return ((std::isnan(rhs.progress) && std::isnan(lhs.progress)) || rhs.progress == lhs.progress);

src/mavsdk/plugins/log_files/log_files_impl.cpp

@@ -1,6 +1,7 @@
 #include "log_files_impl.h"
 #include "mavsdk_impl.h"
 #include "filesystem_include.h"
+#include "unused.h"
 
 #include <algorithm>
 #include <cmath>
@@ -202,6 +203,23 @@ void LogFilesImpl::list_timeout()
     }
 }
 
+std::pair<LogFiles::Result, LogFiles::ProgressData>
+LogFilesImpl::download_log_file(LogFiles::Entry entry, const std::string& file_path)
+{
+    auto prom =
+        std::make_shared<std::promise<std::pair<LogFiles::Result, LogFiles::ProgressData>>>();
+    auto future_result = prom->get_future();
+
+    download_log_file_async(
+        entry, file_path, [prom](LogFiles::Result result, LogFiles::ProgressData progress) {
+            UNUSED(progress);
+            if (result != LogFiles::Result::Next) {
+                prom->set_value(std::make_pair(result, progress));
+            }
+        });
+    return future_result.get();
+}
+
 void LogFilesImpl::download_log_file_async(
     LogFiles::Entry entry, const std::string& file_path, LogFiles::DownloadLogFileCallback callback)
 {
@@ -295,6 +313,21 @@ void LogFilesImpl::download_log_file_async(
     }
 }
 
+LogFiles::Result LogFilesImpl::erase_all_log_files()
+{
+    mavlink_message_t msg;
+    mavlink_msg_log_erase_pack(
+        _parent->get_own_system_id(),
+        _parent->get_own_component_id(),
+        &msg,
+        _parent->get_system_id(),
+        MAV_COMP_ID_AUTOPILOT1);
+    _parent->send_message(msg);
+
+    // TODO: find a good way to know about the success or failure of the operation
+    return LogFiles::Result::Success;
+}
+
 std::size_t LogFilesImpl::determine_part_end()
 {
     // Assumes to have the lock for _data.mutex.

src/mavsdk/plugins/log_files/log_files_impl.h

@@ -23,11 +23,15 @@ class LogFilesImpl : public PluginImplBase {
     std::pair<LogFiles::Result, std::vector<LogFiles::Entry>> get_entries();
     void get_entries_async(LogFiles::GetEntriesCallback callback);
 
+    std::pair<LogFiles::Result, LogFiles::ProgressData>
+    download_log_file(LogFiles::Entry entry, const std::string& file_path);
     void download_log_file_async(
         LogFiles::Entry entry,
         const std::string& file_path,
         LogFiles::DownloadLogFileCallback callback);
 
+    LogFiles::Result erase_all_log_files();
+
 private:
     void request_end();