Create shared/cpp library and move Diagnostics there

shared/cpp/Diagnostics.cpp

@@ -0,0 +1,75 @@
+#include "Diagnostics.h"
+
+#include <fmt/format.h>
+#include <fmt/chrono.h>
+
+#include "absl/strings/str_join.h"
+#include "absl/strings/str_cat.h"
+
+namespace codeql {
+
+namespace {
+std::string_view severityToString(Diagnostic::Severity severity) {
+  using S = Diagnostic::Severity;
+  switch (severity) {
+    case S::note:
+      return "note";
+    case S::warning:
+      return "warning";
+    case S::error:
+      return "error";
+    default:
+      return "unknown";
+  }
+}
+}  // namespace
+
+nlohmann::json Diagnostic::json(const std::chrono::system_clock::time_point& timestamp,
+                                std::string_view message) const {
+  nlohmann::json ret{
+      {"source",
+       {
+           {"id", absl::StrJoin({extractorName, programName, id}, "/")},
+           {"name", name},
+           {"extractorName", extractorName},
+       }},
+      {"visibility",
+       {
+           {"statusPage", has(Visibility::statusPage)},
+           {"cliSummaryTable", has(Visibility::cliSummaryTable)},
+           {"telemetry", has(Visibility::telemetry)},
+       }},
+      {"severity", severityToString(severity)},
+      {"markdownMessage", absl::StrCat(message, "\n\n", action)},
+      {"timestamp", fmt::format("{:%FT%T%z}", timestamp)},
+  };
+  if (location) {
+    ret["location"] = location->json();
+  }
+  return ret;
+}
+
+std::string Diagnostic::abbreviation() const {
+  if (location) {
+    return absl::StrCat(id, "@", location->str());
+  }
+  return std::string{id};
+}
+
+bool Diagnostic::has(Visibility v) const {
+  return (visibility & v) != Visibility::none;
+}
+
+nlohmann::json DiagnosticsLocation::json() const {
+  nlohmann::json ret{{"file", file}};
+  if (startLine) ret["startLine"] = startLine;
+  if (startColumn) ret["startColumn"] = startColumn;
+  if (endLine) ret["endLine"] = endLine;
+  if (endColumn) ret["endColumn"] = endColumn;
+  return ret;
+}
+
+std::string DiagnosticsLocation::str() const {
+  return absl::StrJoin(std::tuple{file, startLine, startColumn, endLine, endColumn}, ":");
+}
+}  // namespace codeql