ResultsFile: Support storing results in a CSV file

The first row of the CSV file contains the general glmark2
invocation information. Subsequent lines contain the benchmark
results.

doc/glmark2.1.in

@@ -55,7 +55,7 @@ Run in fullscreen mode (equivalent to --size -1x-1)
 The types of results to report for each benchmark, as a ':' separated list [fps,cpu,shader]
 .TP
 \fB\-\-results-file\fR RESULTS-FILE
-The file to save the results to, in the format determined by the file extension
+The file to save the results to, in the format determined by the file extension [csv]
 .TP
 \fB\-\-winsys-options\fR OPTS
 A list of 'opt=value' pairs for window system specific options, separated by ':'

src/options.cpp

@@ -223,7 +223,7 @@ Options::print_help()
            "      --results RESULTS  The types of results to report for each benchmark,\n"
            "                         as a ':' separated list [fps,cpu,shader]\n"
            "      --results-file F   The file to save the results to, in the format determined\n"
-           "                         by the file extension\n"
+           "                         by the file extension [csv]\n"
            "      --winsys-options O A list of 'opt=value' pairs for window system specific\n"
            "                         options, separated by ':'\n"
            "  -l, --list-scenes      Display information about the available scenes\n"

src/results-file.cpp

@@ -24,6 +24,7 @@
 #include "log.h"
 
 #include <fstream>
+#include <sstream>
 
 namespace
 {
@@ -45,6 +46,64 @@ class NullResultsFile : public ResultsFile
     }
 };
 
+std::string escape_csv_text(const std::string &str)
+{
+    std::stringstream ss;
+
+    for (auto c : str)
+    {
+        switch (c)
+        {
+            case '"': ss << "\"\""; break;
+            default: ss << c; break;
+        }
+    }
+
+    return ss.str();
+}
+
+class CSVResultsFile : public ResultsFile
+{
+public:
+    CSVResultsFile(std::ofstream &&fs) : fs{std::move(fs)} {}
+
+    std::string type() override { return "CSV"; }
+
+    void begin() override {}
+    void end() override {}
+
+    void begin_info() override
+    {
+        first_field = true;
+    }
+
+    void end_info() override
+    {
+        fs << std::endl;
+    }
+
+    void begin_benchmark() override
+    {
+        first_field = true;
+    }
+
+    void end_benchmark() override
+    {
+        fs << std::endl;
+    }
+
+    void add_field(const std::string &name, const std::string &value) override
+    {
+        static_cast<void>(name);
+        fs << (first_field ? "\"" : ",\"") << escape_csv_text(value) << "\"";
+        first_field = false;
+    }
+
+private:
+    std::ofstream fs;
+    bool first_field = true;
+};
+
 std::string get_file_extension(const std::string &str)
 {
     auto i = str.rfind('.');
@@ -81,9 +140,20 @@ bool ResultsFile::init(const std::string &file)
         return false;
     }
 
-    Log::error("Results file type %s is not supported\n", file.c_str());
+    if (ext == ".csv")
+    {
+        ResultsFile::singleton = std::make_unique<CSVResultsFile>(std::move(fs));
+    }
+    else
+    {
+        Log::error("Results file type %s is not supported\n", file.c_str());
+        return false;
+    }
+
+    Log::debug("Writing results to %s file %s\n",
+               ResultsFile::get().type().c_str(), file.c_str());
 
-    return false;
+    return true;
 }
 
 ResultsFile& ResultsFile::get()