Introducing MemoryMappedExternalResource for creating an external...

src/utils.cc

Index: src/utils.cc
===================================================================
--- src/utils.cc	(revision 6353)
+++ src/utils.cc	(working copy)
@@ -276,4 +276,96 @@
 }
 
 
+MemoryMappedExternalResource::MemoryMappedExternalResource(const char* filename)
+    : filename_(NULL),
+      data_(NULL),
+      length_(0),
+      remove_file_on_cleanup_(false) {
+  Init(filename);
+}
+
+
+MemoryMappedExternalResource::
+    MemoryMappedExternalResource(const char* filename,
+                                 bool remove_file_on_cleanup)
+    : filename_(NULL),
+      data_(NULL),
+      length_(0),
+      remove_file_on_cleanup_(remove_file_on_cleanup) {
+  Init(filename);
+}
+
+
+MemoryMappedExternalResource::~MemoryMappedExternalResource() {
+  // Release the resources if we had successfully acquired them:
+  if (file_ != NULL) {
+    delete file_;
+    if (remove_file_on_cleanup_) {
+      OS::Remove(filename_);
+    }
+    DeleteArray<char>(filename_);
+  }
+}
+
+
+void MemoryMappedExternalResource::Init(const char* filename) {
+  file_ = OS::MemoryMappedFile::open(filename);
+  if (file_ != NULL) {
+    filename_ = StrDup(filename);
+    data_ = reinterpret_cast<char*>(file_->memory());
+    length_ = file_->size();
+  }
+}
+
+
+bool MemoryMappedExternalResource::EnsureIsAscii(bool abort_if_failed) const {
+  bool is_ascii = true;
+
+  int line_no = 1;
+  const char* start_of_line = data_;
+  const char* end = data_ + length_;
+  for (const char* p = data_; p < end; p++) {
+    char c = *p;
+    if ((c & 0x80) != 0) {
+      // Non-ascii detected:
+      is_ascii = false;
+
+      // Report the error and abort if appropriate:
+      if (abort_if_failed) {
+        int char_no = (p - start_of_line) - 1;
+
+        ASSERT(filename_ != NULL);
+        PrintF("\n\n\n"
+               "Abort: Non-Ascii character 0x%.2x in file %s line %d char %d",
+               c, filename_, line_no, char_no);
+
+        // Allow for some context up to kNumberOfLeadingContextChars chars
+        // before the offending non-ascii char to help the user see where
+        // the offending char is.
+        const int kNumberOfLeadingContextChars = 10;
+        const char* err_context = p - kNumberOfLeadingContextChars;
+        if (err_context < data_) {
+          err_context = data_;
+        }
+        // Compute the length of the error context and print it.
+        int err_context_length = p - err_context;
+        if (err_context_length != 0) {
+          PrintF(" after \"%.*s\"", err_context_length, err_context);
+        }
+        PrintF(".\n\n\n");
+        OS::Abort();
+      }
+
+      break;  // Non-ascii detected.  No need to continue scanning.
+    }
+    if (c == '\n') {
+      start_of_line = p;
+      line_no++;
+    }
+  }
+
+  return is_ascii;
+}
+
+
 } }  // namespace v8::internal