src/share/vm/logging/logStream.cpp

rev 13106 : imported patch 8181917-refactor-ul-logstream-alt1-api-changes
rev 13107 : imported patch 8181917-refactor-ul-logstream-alt1-logstream-optimization

*** 24,40 ****
  
  #include "precompiled.hpp"
  #include "logging/log.hpp"
  #include "logging/logStream.hpp"
  
  void LogStream::write(const char* s, size_t len) {
    if (len > 0 && s[len - 1] == '\n') {
!     _current_line.write(s, len - 1);
!     _current_line.write("\0", 1);
!     _log_handle.print("%s", _current_line.base());
      _current_line.reset();
    } else {
!     _current_line.write(s, len);
    }
    update_position(s, len);
  }
  
--- 24,83 ----
  
  #include "precompiled.hpp"
  #include "logging/log.hpp"
  #include "logging/logStream.hpp"
  
+ LogStream::LineBuffer::LineBuffer()
+  : _buf(_smallbuf), _cap(sizeof(_smallbuf)), _pos(0)
+ {
+   _buf[0] = '\0';
+ }
+ 
+ LogStream::LineBuffer::~LineBuffer() {
+   assert(_pos == 0, "still outstanding bytes in the line buffer");
+   if (_buf != _smallbuf) {
+     os::free(_buf);
+   }
+ }
+ 
+ void LogStream::LineBuffer::ensure_cap(size_t atleast) {
+   assert(_cap >= sizeof(_smallbuf), "sanity");
+   if (_cap < atleast) { 
+     const size_t newcap = MAX2(_cap * 2, atleast * 2);
+     char* const newbuf = (char*) os::malloc(newcap, mtLogging);
+     if (_pos > 0) { // preserve old content
+       memcpy(newbuf, _buf, _pos + 1); // ..including trailing zero
+     }
+     if (_buf != _smallbuf) {
+       os::free(_buf);
+     }
+     _buf = newbuf;
+     _cap = newcap;
+   }
+   assert(_cap >= atleast, "sanity");
+ }
+ 
+ void LogStream::LineBuffer::append(const char* s, size_t len) {
+   assert(_buf[_pos] == '\0', "sanity");
+   const size_t remaining = _cap - _pos;
+   ensure_cap(remaining + len + 1);
+   memcpy(_buf + _pos, s, len);
+   _pos += len;
+   _buf[_pos] = '\0';
+ }
+     
+ void LogStream::LineBuffer::reset() {
+   _pos = 0;
+   _buf[_pos] = '\0';
+ }
+ 
  void LogStream::write(const char* s, size_t len) {
    if (len > 0 && s[len - 1] == '\n') {
!     _current_line.append(s, len - 1); // omit the newline.
!     _log_handle.print("%s", _current_line.ptr());
      _current_line.reset();
    } else {
!     _current_line.append(s, len);
    }
    update_position(s, len);
  }