New dart CLI option to create a snapshot depfile. (#29165)

runtime/bin/loader.cc

@@ -12,6 +12,7 @@
 #include "bin/lockers.h"
 #include "bin/utils.h"
 #include "include/dart_tools_api.h"
+#include "platform/growable_array.h"
 
 namespace dart {
 namespace bin {
@@ -283,6 +284,28 @@ static bool PathContainsSeparator(const char* path) {
 }
 
 
+void Loader::AddDependencyLocked(Loader* loader, const char* resolved_uri) {
+  MallocGrowableArray<char*>* dependencies =
+      loader->isolate_data_->dependencies();
+  if (dependencies == NULL) {
+    return;
+  }
+  uint8_t* scoped_file_path = NULL;
+  intptr_t scoped_file_path_length = -1;
+  Dart_Handle uri = Dart_NewStringFromCString(resolved_uri);
+  ASSERT(!Dart_IsError(uri));
+  Dart_Handle result = Loader::ResolveAsFilePath(uri, &scoped_file_path,
+                                                 &scoped_file_path_length);
+  if (Dart_IsError(result)) {
+    Log::Print("Error resolving dependency: %s\n", Dart_GetError(result));
+    return;
+  }
+  dependencies->Add(StringUtils::StrNDup(
+      reinterpret_cast<const char*>(scoped_file_path),
+      scoped_file_path_length));
+}
+
+
 bool Loader::ProcessResultLocked(Loader* loader, Loader::IOResult* result) {
   // We have to copy everything we care about out of |result| because after
   // dropping the lock below |result| may no longer valid.
@@ -296,6 +319,8 @@ bool Loader::ProcessResultLocked(Loader* loader, Loader::IOResult* result) {
         Dart_NewStringFromCString(reinterpret_cast<char*>(result->library_uri));
   }
 
+  AddDependencyLocked(loader, result->resolved_uri);
+
   // A negative result tag indicates a loading error occurred in the service
   // isolate. The payload is a C string of the error message.
   if (result->tag < 0) {

runtime/bin/loader.h

@@ -108,6 +108,9 @@ class Loader {
   /// Blocks the caller until the loader is finished.
   void BlockUntilComplete(ProcessResult process_result);
 
+  /// Saves a script dependency when applicable.
+  static void AddDependencyLocked(Loader* loader, const char* resolved_uri);
+
   /// Returns false if |result| is an error and the loader should quit.
   static bool ProcessResultLocked(Loader* loader, IOResult* result);
 

runtime/bin/main.cc

@@ -27,6 +27,7 @@
 #include "bin/utils.h"
 #include "bin/vmservice_impl.h"
 #include "platform/globals.h"
+#include "platform/growable_array.h"
 #include "platform/hashmap.h"
 #include "platform/text_buffer.h"
 #if !defined(DART_PRECOMPILER)
@@ -60,6 +61,7 @@ enum SnapshotKind {
   kAppJIT,
 };
 static SnapshotKind gen_snapshot_kind = kNone;
+static const char* snapshot_deps_filename = NULL;
 
 static bool use_dart_frontend = false;
 
@@ -372,6 +374,13 @@ static bool ProcessSnapshotKindOption(const char* kind,
 }
 
 
+static bool ProcessSnapshotDepsFilenameOption(const char* filename,
+                                              CommandLineOptions* vm_options) {
+  snapshot_deps_filename = filename;
+  return true;
+}
+
+
 static bool ProcessEnableVmServiceOption(const char* option_value,
                                          CommandLineOptions* vm_options) {
   ASSERT(option_value != NULL);
@@ -553,6 +562,7 @@ static struct {
     {"--observe", ProcessObserveOption},
     {"--snapshot=", ProcessSnapshotFilenameOption},
     {"--snapshot-kind=", ProcessSnapshotKindOption},
+    {"--snapshot-depfile=", ProcessSnapshotDepsFilenameOption},
     {"--use-blobs", ProcessUseBlobsOption},
     {"--save-feedback=", ProcessSaveFeedbackOption},
     {"--load-feedback=", ProcessLoadFeedbackOption},
@@ -688,7 +698,8 @@ static int ParseArguments(int argc,
     Log::PrintErr("Empty package file name specified.\n");
     return -1;
   }
-  if ((gen_snapshot_kind != kNone) && (snapshot_filename == NULL)) {
+  if (((gen_snapshot_kind != kNone) || (snapshot_deps_filename != NULL)) &&
+      (snapshot_filename == NULL)) {
     Log::PrintErr("Generating a snapshot requires a filename (--snapshot).\n");
     return -1;
   }
@@ -783,7 +794,6 @@ static void SnapshotOnExitHook(int64_t exit_code) {
   }
 }
 
-
 // Returns newly created Isolate on success, NULL on failure.
 static Dart_Isolate CreateIsolateAndSetupHelper(bool is_main_isolate,
                                                 const char* script_uri,
@@ -880,6 +890,9 @@ static Dart_Isolate CreateIsolateAndSetupHelper(bool is_main_isolate,
 
   IsolateData* isolate_data =
       new IsolateData(script_uri, package_root, packages_config, app_snapshot);
+  if (is_main_isolate && (snapshot_deps_filename != NULL)) {
+    isolate_data->set_dependencies(new MallocGrowableArray<char*>());
+  }
   // If the script is a Kernel binary, then we will try to bootstrap from the
   // script.
   Dart_Isolate isolate =
@@ -1419,7 +1432,38 @@ bool RunMainIsolate(const char* script_name, CommandLineOptions* dart_options) {
     }
   }
 
+  if (snapshot_deps_filename != NULL) {
+    IsolateData* isolate_data =
+        reinterpret_cast<IsolateData*>(Dart_IsolateData(isolate));
+    ASSERT(isolate_data != NULL);
+    MallocGrowableArray<char*>* dependencies = isolate_data->dependencies();
+    ASSERT(dependencies != NULL);
+    File* file = File::Open(snapshot_deps_filename, File::kWriteTruncate);
+    if (file == NULL) {
+      ErrorExit(kErrorExitCode,
+                "Error: Unable to open snapshot depfile: %s\n\n",
+                snapshot_deps_filename);
+    }
+    bool success = true;
+    success &= file->Print("%s: ", snapshot_filename);
+    for (intptr_t i = 0; i < dependencies->length(); i++) {
+      char* dep = dependencies->At(i);
+      success &= file->Print("%s ", dep);
+      free(dep);
+    }
+    success &= file->Print("\n");
+    if (!success) {
+      ErrorExit(kErrorExitCode,
+                "Error: Unable to write snapshot depfile: %s\n\n",
+                snapshot_deps_filename);
+    }
+    file->Release();
+    isolate_data->set_dependencies(NULL);
+    delete dependencies;
+  }
+
   Dart_ExitScope();
+
   // Shutdown the isolate.
   Dart_ShutdownIsolate();