apphandler: Add storage for Get/Set System Info Parameter

All but one standard System Info Parameter and most (all?) OEM
parameters are string type. Add a interface to connect string callbacks
to System Info Parameter selector codes. Also add a convenience call
that can connect a static string to a parameter selector code.

Change-Id: I5e35d0418b8ddf5b2575fac093acfc7d7ca2217c
Signed-off-by: Xo Wang <xow@google.com>
Signed-off-by: Patrick Venture <venture@google.com>

1 files changed, 33 insertions, 0 deletions

diff --git a/sys_info_param.cpp b/sys_info_param.cpp
new file mode 100644
index 0000000..c9bee32
--- /dev/null
+++ b/sys_info_param.cpp
@@ -0,0 +1,33 @@
+#include "sys_info_param.hpp"
+
+std::tuple<bool, std::string>
+    SysInfoParamStore::lookup(uint8_t paramSelector) const
+{
+    const auto iterator = params.find(paramSelector);
+    if (iterator == params.end())
+    {
+        return std::make_tuple(false, "");
+    }
+
+    auto& callback = iterator->second;
+    auto s = callback();
+    return std::make_tuple(true, s);
+}
+
+void SysInfoParamStore::update(uint8_t paramSelector, const std::string& s)
+{
+    // Add a callback that captures a copy of the string passed and returns it
+    // when invoked.
+
+    // clang-format off
+    update(paramSelector, [s]() {
+        return s;
+    });
+    // clang-format on
+}
+
+void SysInfoParamStore::update(uint8_t paramSelector,
+                               const std::function<std::string()>& callback)
+{
+    params[paramSelector] = callback;
+}