Added new ReadFileToString API with a max_size argument

base/file_util.cc

Index: base/file_util.cc
diff --git a/base/file_util.cc b/base/file_util.cc
index e44f713cdb31828010ad9be92739a3d021dc4685..902c010aa48752ae0cb62450613a81f323b5f981 100644
--- a/base/file_util.cc
+++ b/base/file_util.cc
@@ -10,6 +10,7 @@
 #include <stdio.h>
 
 #include <fstream>
+#include <limits>
 
 #include "base/files/file_enumerator.h"
 #include "base/files/file_path.h"
@@ -126,7 +127,9 @@ bool TextContentsEqual(const FilePath& filename1, const FilePath& filename2) {
   return true;
 }
 
-bool ReadFileToString(const FilePath& path, std::string* contents) {
+bool ReadFileToString(const FilePath& path,
+                      std::string* contents,
+                      size_t max_size) {
   if (path.ReferencesParent())
     return false;
   FILE* file = OpenFile(path, "rb");
@@ -136,7 +139,18 @@ bool ReadFileToString(const FilePath& path, std::string* contents) {
 
   char buf[1 << 16];
   size_t len;
+  size_t size = 0;
+
+  // Many files supplied in path have incorrect size (proc files, streams etc)

[bartfab (slow), 2014/02/12 16:27:11]

Nit 1: s/path/|path|/
Nit 2: s/etc/etc./
Nit 3: End the sentence after the bracket. Then, start a new sentence by
capitalizing "Hence" on the next line.

[kaliamoorthi, 2014/02/17 11:09:41]

Done.

+  // hence the file is read sequentially as opposed to one-shot read.

[bartfab (slow), 2014/02/12 16:27:11]

Nit 1: Add comma after "hence."
Nit 2: s/one-shot/a one-shot/

[kaliamoorthi, 2014/02/17 11:09:41]

Done.

   while ((len = fread(buf, 1, sizeof(buf), file)) > 0) {
+    if ((max_size - size) < len) {
+      if (contents)
+        contents->clear();
+      CloseFile(file);
+      return false;
+    }
+    size += len;
     if (contents)
       contents->append(buf, len);
   }
@@ -145,6 +159,10 @@ bool ReadFileToString(const FilePath& path, std::string* contents) {
   return true;
 }
 
+bool ReadFileToString(const FilePath& path, std::string* contents) {
+  return ReadFileToString(path, contents, std::numeric_limits<size_t>::max());
+}
+
 bool IsDirectoryEmpty(const FilePath& dir_path) {
   FileEnumerator files(dir_path, false,
       FileEnumerator::FILES | FileEnumerator::DIRECTORIES);