Remove locks from leveldb's stdio on linux/CrOS.

After being in stable for a few weeks it has not found any unsafe thread
usage.

BUG=230154

Review URL: https://chromiumcodereview.appspot.com/23440039

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@224649 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 7 insertions, 43 deletions

diff --git a/third_party/leveldatabase/env_chromium.cc b/third_party/leveldatabase/env_chromium.cc
index ed0acfd..f36d691 100644
--- a/third_party/leveldatabase/env_chromium.cc
+++ b/third_party/leveldatabase/env_chromium.cc
@@ -51,15 +51,15 @@ namespace {
 #if (defined(OS_POSIX) && !defined(OS_LINUX)) || defined(OS_WIN)
 // The following are glibc-specific
 
-size_t fread_wrapper(void *ptr, size_t size, size_t n, FILE *file) {
+size_t fread_unlocked(void *ptr, size_t size, size_t n, FILE *file) {
   return fread(ptr, size, n, file);
 }
 
-size_t fwrite_wrapper(const void *ptr, size_t size, size_t n, FILE *file) {
+size_t fwrite_unlocked(const void *ptr, size_t size, size_t n, FILE *file) {
   return fwrite(ptr, size, n, file);
 }
 
-int fflush_wrapper(FILE *file) {
+int fflush_unlocked(FILE *file) {
   return fflush(file);
 }
 
@@ -73,42 +73,6 @@ int fdatasync(int fildes) {
 }
 #endif
 
-#else
-
-class TryToLockFILE {
-  // This class should be deleted if it doesn't turn up anything useful after
-  // going to stable (chrome 29).
- public:
-  TryToLockFILE(FILE* file) : file_to_unlock_(NULL) {
-    if (ftrylockfile(file) == 0)
-      file_to_unlock_ = file;
-    else
-      UMA_HISTOGRAM_BOOLEAN("LevelDBEnv.All.SafeThreadAccess", false);
-  }
-  ~TryToLockFILE() {
-    if (file_to_unlock_)
-      funlockfile(file_to_unlock_);
-  }
-
- private:
-  FILE* file_to_unlock_;
-};
-
-size_t fread_wrapper(void *ptr, size_t size, size_t n, FILE *file) {
-  TryToLockFILE lock(file);
-  return fread_unlocked(ptr, size, n, file);
-}
-
-size_t fwrite_wrapper(const void *ptr, size_t size, size_t n, FILE *file) {
-  TryToLockFILE lock(file);
-  return fwrite_unlocked(ptr, size, n, file);
-}
-
-int fflush_wrapper(FILE *file) {
-  TryToLockFILE lock(file);
-  return fflush_unlocked(file);
-}
-
 #endif
 
 // Wide-char safe fopen wrapper.
@@ -188,7 +152,7 @@ class ChromiumSequentialFile: public SequentialFile {
 
   virtual Status Read(size_t n, Slice* result, char* scratch) {
     Status s;
-    size_t r = fread_wrapper(scratch, 1, n, file_);
+    size_t r = fread_unlocked(scratch, 1, n, file_);
     *result = Slice(scratch, r);
     if (r < n) {
       if (feof(file_)) {
@@ -474,7 +438,7 @@ Status ChromiumWritableFile::Append(const Slice& data) {
     tracker_->DidSyncDir(filename_);
   }
 
-  size_t r = fwrite_wrapper(data.data(), 1, data.size(), file_);
+  size_t r = fwrite_unlocked(data.data(), 1, data.size(), file_);
   if (r != data.size()) {
     int saved_errno = errno;
     uma_logger_->RecordOSError(kWritableFileAppend, saved_errno);
@@ -496,7 +460,7 @@ Status ChromiumWritableFile::Close() {
 
 Status ChromiumWritableFile::Flush() {
   Status result;
-  if (HANDLE_EINTR(fflush_wrapper(file_))) {
+  if (HANDLE_EINTR(fflush_unlocked(file_))) {
     int saved_errno = errno;
     result = MakeIOError(
         filename_, strerror(saved_errno), kWritableFileFlush, saved_errno);
@@ -510,7 +474,7 @@ Status ChromiumWritableFile::Sync() {
   Status result;
   int error = 0;
 
-  if (HANDLE_EINTR(fflush_wrapper(file_)))
+  if (HANDLE_EINTR(fflush_unlocked(file_)))
     error = errno;
   // Sync even if fflush gave an error; perhaps the data actually got out,
   // even though something went wrong.