Record UMA statistics for file_stream operations.

net/base/file_stream_posix.cc

Index: net/base/file_stream_posix.cc
diff --git a/net/base/file_stream_posix.cc b/net/base/file_stream_posix.cc
index 68732e3aac39fa6db4e34ffe93b96c79b3d64b7f..85808ff1807f9aa934bc10cb87d65e812047525f 100644
--- a/net/base/file_stream_posix.cc
+++ b/net/base/file_stream_posix.cc
@@ -25,6 +25,7 @@
 #include "base/threading/thread_restrictions.h"
 #include "base/threading/worker_pool.h"
 #include "base/synchronization/waitable_event.h"
+#include "net/base/file_stream_metrics.h"
 #include "net/base/net_errors.h"
 
 #if defined(OS_ANDROID)
@@ -62,50 +63,64 @@ int64 MapErrorCode(int err) {
 
 // ReadFile() is a simple wrapper around read() that handles EINTR signals and
 // calls MapErrorCode() to map errno to net error codes.
-int ReadFile(base::PlatformFile file, char* buf, int buf_len) {
+int ReadFile(base::PlatformFile file, char* buf, int buf_len, bool record_uma) {
   base::ThreadRestrictions::AssertIOAllowed();
   // read(..., 0) returns 0 to indicate end-of-file.
 
   // Loop in the case of getting interrupted by a signal.
   ssize_t res = HANDLE_EINTR(read(file, buf, static_cast<size_t>(buf_len)));
-  if (res == static_cast<ssize_t>(-1))
-    return MapErrorCode(errno);
+  if (res == static_cast<ssize_t>(-1)) {
+    int error = errno;
+    if (record_uma)
+      RecordFileError(error, FILE_ERROR_SOURCE_READ);
+    return MapErrorCode(error);
+  }
   return static_cast<int>(res);
 }
 
 void ReadFileTask(base::PlatformFile file,
                   char* buf,
                   int buf_len,
+                  bool record_uma,
                   CompletionCallback* callback) {
-  callback->Run(ReadFile(file, buf, buf_len));
+  callback->Run(ReadFile(file, buf, buf_len, record_uma));
 }
 
 // WriteFile() is a simple wrapper around write() that handles EINTR signals and
 // calls MapErrorCode() to map errno to net error codes.  It tries to write to
 // completion.
-int WriteFile(base::PlatformFile file, const char* buf, int buf_len) {
+int WriteFile(base::PlatformFile file, const char* buf, int buf_len,
+              bool record_uma) {
   base::ThreadRestrictions::AssertIOAllowed();
   ssize_t res = HANDLE_EINTR(write(file, buf, buf_len));
-  if (res == -1)
-    return MapErrorCode(errno);
+  if (res == -1) {
+    int error = errno;
+    if (record_uma)
+      RecordFileError(error, FILE_ERROR_SOURCE_WRITE);
+    return MapErrorCode(error);
+  }
   return res;
 }
 
 void WriteFileTask(base::PlatformFile file,
                    const char* buf,
-                   int buf_len,
+                   int buf_len, bool record_uma,
                    CompletionCallback* callback) {
-  callback->Run(WriteFile(file, buf, buf_len));
+  callback->Run(WriteFile(file, buf, buf_len, record_uma));
 }
 
 // FlushFile() is a simple wrapper around fsync() that handles EINTR signals and
 // calls MapErrorCode() to map errno to net error codes.  It tries to flush to
 // completion.
-int FlushFile(base::PlatformFile file) {
+int FlushFile(base::PlatformFile file, bool record_uma) {
   base::ThreadRestrictions::AssertIOAllowed();
   ssize_t res = HANDLE_EINTR(fsync(file));
-  if (res == -1)
-    return MapErrorCode(errno);
+  if (res == -1) {
+    int error = errno;
+    if (record_uma)
+      RecordFileError(error, FILE_ERROR_SOURCE_FLUSH);
+    return MapErrorCode(error);
+  }
   return res;
 }
 
@@ -141,10 +156,10 @@ class FileStream::AsyncContext {
 
   // These methods post synchronous read() and write() calls to a WorkerThread.
   void InitiateAsyncRead(
-      base::PlatformFile file, char* buf, int buf_len,
+      base::PlatformFile file, char* buf, int buf_len, bool record_uma,
       CompletionCallback* callback);
   void InitiateAsyncWrite(
-      base::PlatformFile file, const char* buf, int buf_len,
+      base::PlatformFile file, const char* buf, int buf_len, bool record_uma,
       CompletionCallback* callback);
 
   CompletionCallback* callback() const { return callback_; }
@@ -211,7 +226,7 @@ FileStream::AsyncContext::~AsyncContext() {
 }
 
 void FileStream::AsyncContext::InitiateAsyncRead(
-    base::PlatformFile file, char* buf, int buf_len,
+    base::PlatformFile file, char* buf, int buf_len, bool record_uma,
     CompletionCallback* callback) {
   DCHECK(!callback_);
   callback_ = callback;
@@ -219,13 +234,13 @@ void FileStream::AsyncContext::InitiateAsyncRead(
   base::WorkerPool::PostTask(FROM_HERE,
                              NewRunnableFunction(
                                  &ReadFileTask,
-                                 file, buf, buf_len,
+                                 file, buf, buf_len, record_uma,
                                  &background_io_completed_callback_),
                              true /* task_is_slow */);
 }
 
 void FileStream::AsyncContext::InitiateAsyncWrite(
-    base::PlatformFile file, const char* buf, int buf_len,
+    base::PlatformFile file, const char* buf, int buf_len, bool record_uma,
     CompletionCallback* callback) {
   DCHECK(!callback_);
   callback_ = callback;
@@ -233,7 +248,7 @@ void FileStream::AsyncContext::InitiateAsyncWrite(
   base::WorkerPool::PostTask(FROM_HERE,
                              NewRunnableFunction(
                                  &WriteFileTask,
-                                 file, buf, buf_len,
+                                 file, buf, buf_len, record_uma,
                                  &background_io_completed_callback_),
                              true /* task_is_slow */);
 }
@@ -274,14 +289,16 @@ void FileStream::AsyncContext::RunAsynchronousCallback() {
 FileStream::FileStream()
     : file_(base::kInvalidPlatformFileValue),
       open_flags_(0),
-      auto_closed_(true) {
+      auto_closed_(false),
+      record_uma_(false) {
   DCHECK(!IsOpen());
 }
 
 FileStream::FileStream(base::PlatformFile file, int flags)
     : file_(file),
       open_flags_(flags),
-      auto_closed_(false) {
+      auto_closed_(false),
+      record_uma_(false) {
   // If the file handle is opened with base::PLATFORM_FILE_ASYNC, we need to
   // make sure we will perform asynchronous File IO to it.
   if (flags & base::PLATFORM_FILE_ASYNC) {
@@ -315,7 +332,10 @@ int FileStream::Open(const FilePath& path, int open_flags) {
   open_flags_ = open_flags;
   file_ = base::CreatePlatformFile(path, open_flags_, NULL, NULL);
   if (file_ == base::kInvalidPlatformFileValue) {
-    return MapErrorCode(errno);
+    int error = errno;
+    if (record_uma_)
+      RecordFileError(error, FILE_ERROR_SOURCE_OPEN);
+    return MapErrorCode(error);
   }
 
   if (open_flags_ & base::PLATFORM_FILE_ASYNC) {
@@ -332,16 +352,23 @@ bool FileStream::IsOpen() const {
 int64 FileStream::Seek(Whence whence, int64 offset) {
   base::ThreadRestrictions::AssertIOAllowed();
 
-  if (!IsOpen())
+  if (!IsOpen()) {
+    if (record_uma_)
+      RecordFileError(EINVAL, FILE_ERROR_SOURCE_IS_NOT_OPEN);
     return ERR_UNEXPECTED;
+  }
 
   // If we're in async, make sure we don't have a request in flight.
   DCHECK(!async_context_.get() || !async_context_->callback());
 
   off_t res = lseek(file_, static_cast<off_t>(offset),
                     static_cast<int>(whence));
-  if (res == static_cast<off_t>(-1))
-    return MapErrorCode(errno);
+  if (res == static_cast<off_t>(-1)) {
+    int error = errno;

[cbentzel, 2011/08/16 13:36:02]

Perhaps a helper function like

MapAndRecordErrorCode(error, record_uma_)

to help minimize duplication here.

[ahendrickson, 2011/08/17 20:12:04]

Done.

+    if (record_uma_)
+      RecordFileError(error, FILE_ERROR_SOURCE_SEEK);
+    return MapErrorCode(error);
+  }
 
   return res;
 }
@@ -349,17 +376,23 @@ int64 FileStream::Seek(Whence whence, int64 offset) {
 int64 FileStream::Available() {
   base::ThreadRestrictions::AssertIOAllowed();
 
-  if (!IsOpen())
+  if (!IsOpen()) {
+    if (record_uma_)

[cbentzel, 2011/08/16 13:36:02]

I don't think it's worth recording these errors related to 

if (!IsOpen())

at the top of many of the functions. It's more of a programming error than
return codes we are seeing from the OS/library calls. 

[ahendrickson, 2011/08/17 20:12:04]

Done.

+      RecordFileError(EINVAL, FILE_ERROR_SOURCE_IS_NOT_OPEN);
     return ERR_UNEXPECTED;
+  }
 
   int64 cur_pos = Seek(FROM_CURRENT, 0);
   if (cur_pos < 0)
     return cur_pos;
 
   struct stat info;
-  if (fstat(file_, &info) != 0)
-    return MapErrorCode(errno);
-
+  if (fstat(file_, &info) != 0) {
+    int error = errno;
+    if (record_uma_)
+      RecordFileError(error, FILE_ERROR_SOURCE_GET_SIZE);
+    return MapErrorCode(error);
+  }
   int64 size = static_cast<int64>(info.st_size);
   DCHECK_GT(size, cur_pos);
 
@@ -368,8 +401,11 @@ int64 FileStream::Available() {
 
 int FileStream::Read(
     char* buf, int buf_len, CompletionCallback* callback) {
-  if (!IsOpen())
+  if (!IsOpen()) {
+    if (record_uma_)
+      RecordFileError(EINVAL, FILE_ERROR_SOURCE_IS_NOT_OPEN);
     return ERR_UNEXPECTED;
+  }
 
   // read(..., 0) will return 0, which indicates end-of-file.
   DCHECK(buf_len > 0);
@@ -379,10 +415,11 @@ int FileStream::Read(
     DCHECK(open_flags_ & base::PLATFORM_FILE_ASYNC);
     // If we're in async, make sure we don't have a request in flight.
     DCHECK(!async_context_->callback());
-    async_context_->InitiateAsyncRead(file_, buf, buf_len, callback);
+    async_context_->InitiateAsyncRead(file_, buf, buf_len, record_uma_,
+                                      callback);
     return ERR_IO_PENDING;
   } else {
-    return ReadFile(file_, buf, buf_len);
+    return ReadFile(file_, buf, buf_len, record_uma_);
   }
 }
 
@@ -412,25 +449,32 @@ int FileStream::Write(
   // write(..., 0) will return 0, which indicates end-of-file.
   DCHECK_GT(buf_len, 0);
 
-  if (!IsOpen())
+  if (!IsOpen()) {
+    if (record_uma_)
+      RecordFileError(EINVAL, FILE_ERROR_SOURCE_IS_NOT_OPEN);
     return ERR_UNEXPECTED;
+  }
 
   if (async_context_.get()) {
     DCHECK(open_flags_ & base::PLATFORM_FILE_ASYNC);
     // If we're in async, make sure we don't have a request in flight.
     DCHECK(!async_context_->callback());
-    async_context_->InitiateAsyncWrite(file_, buf, buf_len, callback);
+    async_context_->InitiateAsyncWrite(file_, buf, buf_len, record_uma_,
+                                       callback);
     return ERR_IO_PENDING;
   } else {
-    return WriteFile(file_, buf, buf_len);
+    return WriteFile(file_, buf, buf_len, record_uma_);
   }
 }
 
 int64 FileStream::Truncate(int64 bytes) {
   base::ThreadRestrictions::AssertIOAllowed();
 
-  if (!IsOpen())
+  if (!IsOpen()) {
+    if (record_uma_)
+      RecordFileError(EINVAL, FILE_ERROR_SOURCE_IS_NOT_OPEN);
     return ERR_UNEXPECTED;
+  }
 
   // We better be open for reading.
   DCHECK(open_flags_ & base::PLATFORM_FILE_WRITE);
@@ -442,14 +486,27 @@ int64 FileStream::Truncate(int64 bytes) {
 
   // And truncate the file.
   int result = ftruncate(file_, bytes);

[cbentzel, 2011/08/16 13:36:02]

This existed before - but we may want to make this HANDLE_EINTR(ftruncate(file_,
bytes)). It looks like EINTR can be a return value during ftruncate - perhaps
only when trying to expand the file rather than shrink it.

[ahendrickson, 2011/08/17 20:12:04]

What does HANDLE_EINTR do?

[cbentzel, 2011/08/18 13:31:27]

HANDLE_EINTR re-executes the function if the errno was EINTR. Many POSIX
functions do this if it's possible that they can be stopped early due to an
interrupt. 

I think this is discussed in W. Richard Stevens Unix Network Programming vol. 1.
 There's probably online resources about it as well.

It's probably a good idea to do this in a separate CL, however.

[ahendrickson, 2011/08/18 15:56:45]

OK, removed.

-  return result == 0 ? seek_position : MapErrorCode(errno);
+  if (result == 0)
+    return seek_position;
+
+  int error = errno;
+  if (record_uma_)
+    RecordFileError(error, FILE_ERROR_SOURCE_SET_EOF);
+  return MapErrorCode(error);
 }
 
 int FileStream::Flush() {
-  if (!IsOpen())
+  if (!IsOpen()) {
+    if (record_uma_)
+      RecordFileError(EINVAL, FILE_ERROR_SOURCE_IS_NOT_OPEN);
     return ERR_UNEXPECTED;
+  }
+
+  return FlushFile(file_, record_uma_);
+}
 
-  return FlushFile(file_);
+void FileStream::EnableRecording() {
+  record_uma_ = true;

[cbentzel, 2011/08/16 13:36:02]

Do you need to do the 

if (async_context_)
  async_context_->EnableRecording()

here as well? You have it in the Win version, and then you could replace passing
in record_uma to all of the function calls on the async_context_.

[ahendrickson, 2011/08/17 20:12:04]

Doing something similar now:  Setting it at the time of the asynchronous
invocation.

[cbentzel, 2011/08/18 13:31:27]

Yup. After the fact I realized how different the two implementations were. Note:
I'm not a huge fan of how the POSIX implementation uses worker threads to handle
IO. Perhaps we should look at async file IO on Posix. Certainly not in this CL
though.

 }
 
 }  // namespace net