just analyse: add --dump-result command line option

The result of the analysis is a JSON object containing the keys
`"artifacts"`, `"runfiles"`, and `"provides"`. This JSON object, by
default, is logged. However, it might be useful to process the data
contained in it, while, for example, developing new rules.

This patch adds a new command line option (`--dump-result`), reserved
to the subcommand `analyse`, to dump the analysis result to the given
file or stdout (if `-` is given).

2 files changed, 25 insertions, 0 deletions

diff --git a/src/buildtool/common/cli.hpp b/src/buildtool/common/cli.hpp
index eded8112..57567cf7 100644
--- a/src/buildtool/common/cli.hpp
+++ b/src/buildtool/common/cli.hpp
@@ -91,6 +91,7 @@ struct DiagnosticArguments {
     std::optional<std::string> dump_targets_graph{std::nullopt};
     std::optional<std::string> dump_anonymous{std::nullopt};
     std::optional<std::string> dump_nodes{std::nullopt};
+    std::optional<std::string> dump_result{std::nullopt};
 };
 
 /// \brief Arguments required for specifying build endpoint.
@@ -398,6 +399,10 @@ static inline auto SetupDiagnosticArguments(
                     clargs->dump_nodes,
                     "Dump nodes of target to file (use - for stdout).")
         ->type_name("PATH");
+    app->add_option("--dump-result",
+                    clargs->dump_result,
+                    "Dump the result of analyse to file (use - for stdout).")
+        ->type_name("PATH");
 }
 
 static inline auto SetupCacheArguments(
diff --git a/src/buildtool/main/diagnose.cpp b/src/buildtool/main/diagnose.cpp
index 2da1c89a..49aefc86 100644
--- a/src/buildtool/main/diagnose.cpp
+++ b/src/buildtool/main/diagnose.cpp
@@ -290,6 +290,23 @@ void DumpNodes(std::string const& file_path, AnalysisResult const& result) {
         os << dump_string << std::endl;
     }
 }
+
+void DumpResult(std::string const& file_path, AnalysisResult const& result) {
+    auto const dump_string = ResultToJson(result.target->Result()).dump();
+    if (file_path == "-") {
+        Logger::Log(
+            LogLevel::Info, "Result of target {}:", result.id.ToString());
+        std::cout << dump_string << std::endl;
+    }
+    else {
+        Logger::Log(LogLevel::Info,
+                    "Dumping result of target {} to file '{}'.",
+                    result.id.ToString(),
+                    file_path);
+        std::ofstream os{file_path};
+        os << dump_string << std::endl;
+    }
+}
 }  // namespace
 
 void DiagnoseResults(AnalysisResult const& result,
@@ -307,6 +324,9 @@ void DiagnoseResults(AnalysisResult const& result,
             2,
             2,
             std::unordered_map<std::string, std::size_t>{{"/provides", 3}}));
+    if (clargs.dump_result) {
+        DumpResult(*clargs.dump_result, result);
+    }
     if (clargs.dump_actions) {
         DumpActions(*clargs.dump_actions, result);
     }