Added new ReadFileToString API with a max_size argument

The CL creates a new API that takes a max_size argument. When the file size exceed the max_size, the API primes the cache and returns false.

BUG=339417

Review URL: https://codereview.chromium.org/157593005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@251771 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 16 insertions, 2 deletions

diff --git a/base/file_util.h b/base/file_util.h
index 7690703..9143c60 100644
--- a/base/file_util.h
+++ b/base/file_util.h
@@ -139,10 +139,24 @@ BASE_EXPORT bool TextContentsEqual(const FilePath& filename1,
 // Read the file at |path| into |contents|, returning true on success.
 // This function fails if the |path| contains path traversal components ('..').
 // |contents| may be NULL, in which case this function is useful for its
-// side effect of priming the disk cache.
-// Useful for unit tests.
+// side effect of priming the disk cache, which is useful for unit tests.
+// The function replaces rather than append to |contents|, further |contents|
+// could be cleared on error.
 BASE_EXPORT bool ReadFileToString(const FilePath& path, std::string* contents);
 
+// Read the file at |path| into |contents|, returning true on success.
+// This function has an additional check on the maximum size of the file.
+// When the file size is greater than |max_size|, the function reads |max_size|
+// bytes into |contents| and returns false.
+// This function fails if the |path| contains path traversal components ('..').
+// |contents| may be NULL, in which case this function is useful for its
+// side effect of priming the disk cache, which is useful for unit tests.
+// The function replaces rather than append to |contents|, further |contents|
+// could be cleared on error.
+BASE_EXPORT bool ReadFileToString(const FilePath& path,
+                                  std::string* contents,
+                                  size_t max_size);
+
 #if defined(OS_POSIX)
 
 // Read exactly |bytes| bytes from file descriptor |fd|, storing the result