Add explicit null checks after string conversions in the shells.

This fixes issue 224.
Review URL: http://codereview.chromium.org/20081

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@1233 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

diff --git a/include/v8.h b/include/v8.h
index 8ee99b4..c9ec030 100644 (file)
--- a/include/v8.h
+++ b/include/v8.h
@@ -859,7 +859,7 @@ class EXPORT String : public Primitive {
    public:
     explicit Utf8Value(Handle<v8::Value> obj);
     ~Utf8Value();
-    char* operator*() { return str_; }
+    char* operator*() const { return str_; }
     int length() { return length_; }
    private:
     char* str_;
@@ -878,7 +878,7 @@ class EXPORT String : public Primitive {
    public:
     explicit AsciiValue(Handle<v8::Value> obj);
     ~AsciiValue();
-    char* operator*() { return str_; }
+    char* operator*() const { return str_; }
     int length() { return length_; }
    private:
     char* str_;
@@ -896,7 +896,7 @@ class EXPORT String : public Primitive {
    public:
     explicit Value(Handle<v8::Value> obj);
     ~Value();
-    uint16_t* operator*() { return str_; }
+    uint16_t* operator*() const { return str_; }
     int length() { return length_; }
    private:
     uint16_t* str_;

diff --git a/samples/shell.cc b/samples/shell.cc
index 39236a9..a9a8350 100644 (file)
--- a/samples/shell.cc
+++ b/samples/shell.cc
@@ -99,6 +99,12 @@ int main(int argc, char* argv[]) {
 }
 
 
+// Extracts a C string from a V8 Utf8Value.
+const char* ToCString(const v8::String::Utf8Value& value) {
+  return *value ? *value : "<string conversion failed>";
+}
+
+
 // The callback that is invoked by v8 whenever the JavaScript 'print'
 // function is called.  Prints its arguments on stdout separated by
 // spaces and ending with a newline.
@@ -112,7 +118,8 @@ v8::Handle<v8::Value> Print(const v8::Arguments& args) {
       printf(" ");
     }
     v8::String::Utf8Value str(args[i]);
-    printf("%s", *str);
+    const char* cstr = ToCString(str);
+    printf("%s", cstr);
   }
   printf("\n");
   return v8::Undefined();
@@ -126,6 +133,9 @@ v8::Handle<v8::Value> Load(const v8::Arguments& args) {
   for (int i = 0; i < args.Length(); i++) {
     v8::HandleScope handle_scope;
     v8::String::Utf8Value file(args[i]);
+    if (*file == NULL) {
+      return v8::ThrowException(v8::String::New("Error loading file"));
+    }
     v8::Handle<v8::String> source = ReadFile(*file);
     if (source.IsEmpty()) {
       return v8::ThrowException(v8::String::New("Error loading file"));
@@ -220,7 +230,8 @@ bool ExecuteString(v8::Handle<v8::String> source,
         // If all went well and the result wasn't undefined then print
         // the returned value.
         v8::String::Utf8Value str(result);
-        printf("%s\n", *str);
+        const char* cstr = ToCString(str);
+        printf("%s\n", cstr);
       }
       return true;
     }
@@ -231,19 +242,22 @@ bool ExecuteString(v8::Handle<v8::String> source,
 void ReportException(v8::TryCatch* try_catch) {
   v8::HandleScope handle_scope;
   v8::String::Utf8Value exception(try_catch->Exception());
+  const char* exception_string = ToCString(exception);
   v8::Handle<v8::Message> message = try_catch->Message();
   if (message.IsEmpty()) {
     // V8 didn't provide any extra information about this error; just
     // print the exception.
-    printf("%s\n", *exception);
+    printf("%s\n", exception_string);
   } else {
     // Print (filename):(line number): (message).
     v8::String::Utf8Value filename(message->GetScriptResourceName());
+    const char* filename_string = ToCString(filename);
     int linenum = message->GetLineNumber();
-    printf("%s:%i: %s\n", *filename, linenum, *exception);
+    printf("%s:%i: %s\n", filename_string, linenum, exception_string);
     // Print line of source code.
     v8::String::Utf8Value sourceline(message->GetSourceLine());
-    printf("%s\n", *sourceline);
+    const char* sourceline_string = ToCString(sourceline);
+    printf("%s\n", sourceline_string);
     // Print wavy underline (GetUnderline is deprecated).
     int start = message->GetStartColumn();
     for (int i = 0; i < start; i++) {

diff --git a/src/d8.cc b/src/d8.cc
index 2f4e817..f3df9ee 100644 (file)
--- a/src/d8.cc
+++ b/src/d8.cc
@@ -93,6 +93,12 @@ Persistent<Context> Shell::utility_context_;
 Persistent<Context> Shell::evaluation_context_;
 
 
+// Converts a V8 value to a C string.
+const char* ToCString(const v8::String::Utf8Value& value) {
+  return *value ? *value : "<string conversion failed>";
+}
+
+
 // Executes a string within the current v8 context.
 bool Shell::ExecuteString(Handle<String> source,
                           Handle<Value> name,
@@ -121,8 +127,9 @@ bool Shell::ExecuteString(Handle<String> source,
       if (print_result && !result->IsUndefined()) {
         // If all went well and the result wasn't undefined then print
         // the returned value.
-        String::Utf8Value str(result);
-        printf("%s\n", *str);
+        v8::String::Utf8Value str(result);
+        const char* cstr = ToCString(str);
+        printf("%s\n", cstr);
       }
       return true;
     }
@@ -139,8 +146,9 @@ Handle<Value> Shell::Print(const Arguments& args) {
     } else {
       printf(" ");
     }
-    String::Utf8Value str(args[i]);
-    printf("%s", *str);
+    v8::String::Utf8Value str(args[i]);
+    const char* cstr = ToCString(str);
+    printf("%s", cstr);
   }
   printf("\n");
   return Undefined();
@@ -151,6 +159,9 @@ Handle<Value> Shell::Load(const Arguments& args) {
   for (int i = 0; i < args.Length(); i++) {
     HandleScope handle_scope;
     String::Utf8Value file(args[i]);
+    if (*file == NULL) {
+      return ThrowException(String::New("Error loading file"));
+    }
     Handle<String> source = ReadFile(*file);
     if (source.IsEmpty()) {
       return ThrowException(String::New("Error loading file"));
@@ -178,20 +189,23 @@ Handle<Value> Shell::Version(const Arguments& args) {
 
 void Shell::ReportException(v8::TryCatch* try_catch) {
   HandleScope handle_scope;
-  String::Utf8Value exception(try_catch->Exception());
+  v8::String::Utf8Value exception(try_catch->Exception());
+  const char* exception_string = ToCString(exception);
   Handle<Message> message = try_catch->Message();
   if (message.IsEmpty()) {
     // V8 didn't provide any extra information about this error; just
     // print the exception.
-    printf("%s\n", *exception);
+    printf("%s\n", exception_string);
   } else {
     // Print (filename):(line number): (message).
-    String::Utf8Value filename(message->GetScriptResourceName());
+    v8::String::Utf8Value filename(message->GetScriptResourceName());
+    const char* filename_string = ToCString(filename);
     int linenum = message->GetLineNumber();
-    printf("%s:%i: %s\n", *filename, linenum, *exception);
+    printf("%s:%i: %s\n", filename_string, linenum, exception_string);
     // Print line of source code.
-    String::Utf8Value sourceline(message->GetSourceLine());
-    printf("%s\n", *sourceline);
+    v8::String::Utf8Value sourceline(message->GetSourceLine());
+    const char* sourceline_string = ToCString(sourceline);
+    printf("%s\n", sourceline_string);
     // Print wavy underline (GetUnderline is deprecated).
     int start = message->GetStartColumn();
     for (int i = 0; i < start; i++) {