Bug 1492090 - Part 1: Fix some comments, remove a #define, and make one fclose call more robust. r=tcampbell

Differential Revision: https://phabricator.services.mozilla.com/D151445

ipc/testshell/XPCShellEnvironment.cpp

@@ -259,9 +259,7 @@ void XPCShellEnvironment::ProcessFile(JSContext* cx, const char* filename,
      * It's not interactive - just execute it.
      *
      * Support the UNIX #! shell hack; gobble the first line if it starts
-     * with '#'.  TODO - this isn't quite compatible with sharp variables,
-     * as a legal js program (using sharp variables) might start with '#'.
-     * But that would require multi-character lookahead.
+     * with '#'.
      */
     int ch = fgetc(file);
     if (ch == '#') {

js/public/CompileOptions.h

@@ -233,8 +233,8 @@ class JS_PUBLIC_API TransitiveCompileOptions {
   bool deoptimizeModuleGlobalVars = false;
 
   /**
-   * |introductionType| is a statically allocated C string: one of "eval",
-   * "Function", or "GeneratorFunction".
+   * |introductionType| is a statically allocated C string. See JSScript.h
+   * for more information.
    */
   const char* introductionType = nullptr;
 

js/src/builtin/TestingFunctions.cpp

@@ -4173,6 +4173,11 @@ static bool DumpHeap(JSContext* cx, unsigned argc, Value* vp) {
   CallArgs args = CallArgsFromVp(argc, vp);
 
   FILE* dumpFile = stdout;
+  auto closeFile = mozilla::MakeScopeExit([&dumpFile] {
+    if (dumpFile != stdout) {
+      fclose(dumpFile);
+    }
+  });
 
   if (args.length() > 1) {
     RootedObject callee(cx, &args.callee());
@@ -4204,10 +4209,6 @@ static bool DumpHeap(JSContext* cx, unsigned argc, Value* vp) {
 
   js::DumpHeap(cx, dumpFile, js::IgnoreNurseryObjects);
 
-  if (dumpFile != stdout) {
-    fclose(dumpFile);
-  }
-
   args.rval().setUndefined();
   return true;
 }

js/src/ctypes/Library.cpp

@@ -177,13 +177,12 @@ JSObject* Library::Create(JSContext* cx, HandleValue path,
   PRLibrary* library = PR_LoadLibraryWithFlags(libSpec, PR_LD_NOW);
 
   if (!library) {
-#define MAX_ERROR_LEN 1024
-    char error[MAX_ERROR_LEN] = "Cannot get error from NSPR.";
+    constexpr size_t MaxErrorLength = 1024;
+    char error[MaxErrorLength] = "Cannot get error from NSPR.";
     uint32_t errorLen = PR_GetErrorTextLength();
-    if (errorLen && errorLen < MAX_ERROR_LEN) {
+    if (errorLen && errorLen < MaxErrorLength) {
       PR_GetErrorText(error);
     }
-#undef MAX_ERROR_LEN
 
     if (JS::StringIsASCII(error)) {
       if (JS::UniqueChars pathCharsUTF8 = JS_EncodeStringToUTF8(cx, pathStr)) {

js/src/vm/JSScript.h

@@ -583,6 +583,8 @@ class ScriptSource {
   // A string indicating how this source code was introduced into the system.
   // This is a constant, statically allocated C string, so does not need memory
   // management.
+  //
+  // TODO: Document the various additional introduction type constants.
   const char* introductionType_ = nullptr;
 
   // Bytecode offset in caller script that generated this code.  This is

js/xpconnect/src/XPCShellImpl.cpp

@@ -793,9 +793,7 @@ static bool ProcessFile(AutoJSAPI& jsapi, const char* filename, FILE* file,
      * It's not interactive - just execute it.
      *
      * Support the UNIX #! shell hack; gobble the first line if it starts
-     * with '#'.  TODO - this isn't quite compatible with sharp variables,
-     * as a legal js program (using sharp variables) might start with '#'.
-     * But that would require multi-character lookahead.
+     * with '#'.
      */
     int ch = fgetc(file);
     if (ch == '#') {