36   assert(_pos == 0, "still outstanding bytes in the line buffer");
  37   if (_buf != _smallbuf) {
  38     os::free(_buf);
  39   }
  40 }
  41 
  42 // try_ensure_cap tries to enlarge the capacity of the internal buffer
  43 // to the given atleast value. May fail if either OOM happens or atleast
  44 // is larger than a reasonable max of 1 M. Caller must not assume
  45 // capacity without checking.
  46 void LogStream::LineBuffer::try_ensure_cap(size_t atleast) {
  47   assert(_cap >= sizeof(_smallbuf), "sanity");
  48   if (_cap < atleast) {
  49     // Cap out at a reasonable max to prevent runaway leaks.
  50     const size_t reasonable_max = 1 * M;
  51     assert(_cap <= reasonable_max, "sanity");
  52     if (_cap == reasonable_max) {
  53       return;
  54     }
  55 
  56     size_t newcap = align_up(atleast + 64, 64);

  57     if (newcap > reasonable_max) {
  58       log_info(logging)("Suspiciously long log line: \"%.100s%s",
  59               _buf, (_pos >= 100 ? "..." : ""));
  60       newcap = reasonable_max;
  61     }
  62 
  63     char* const newbuf = (char*) os::malloc(newcap, mtLogging);
  64     if (newbuf == NULL) { // OOM. Leave object unchanged.
  65       return;
  66     }
  67     if (_pos > 0) { // preserve old content
  68       memcpy(newbuf, _buf, _pos + 1); // ..including trailing zero
  69     }
  70     if (_buf != _smallbuf) {
  71       os::free(_buf);
  72     }
  73     _buf = newbuf;
  74     _cap = newcap;
  75   }
  76   assert(_cap >= atleast, "sanity");
  77 }
  78 
  79 void LogStream::LineBuffer::append(const char* s, size_t len) {
  80   assert(_buf[_pos] == '\0', "sanity");
  81   assert(_pos < _cap, "sanity");
  82   try_ensure_cap(_pos + len + 1);

  83   // try_ensure_cap may not have enlarged the capacity to the full requested
  84   // extend or may have not worked at all. In that case, just gracefully work
  85   // with what we have already; just truncate if necessary.
  86   if (_pos + len + 1 > _cap) {
  87     len = _cap - _pos - 1;
  88     if (len == 0) {
  89       return;
  90     }
  91   }
  92   memcpy(_buf + _pos, s, len);
  93   _pos += len;
  94   _buf[_pos] = '\0';
  95 }
  96 
  97 void LogStream::LineBuffer::reset() {
  98   _pos = 0;
  99   _buf[_pos] = '\0';
 100 }
 101 
 102 void LogStream::write(const char* s, size_t len) {
 103   if (len > 0 && s[len - 1] == '\n') {
 104     _current_line.append(s, len - 1); // omit the newline.
 105     _log_handle.print("%s", _current_line.ptr());
 106     _current_line.reset();
 107   } else {
 108     _current_line.append(s, len);
 109   }
 110   update_position(s, len);
 111 }
 112 

  36   assert(_pos == 0, "still outstanding bytes in the line buffer");
  37   if (_buf != _smallbuf) {
  38     os::free(_buf);
  39   }
  40 }
  41 
  42 // try_ensure_cap tries to enlarge the capacity of the internal buffer
  43 // to the given atleast value. May fail if either OOM happens or atleast
  44 // is larger than a reasonable max of 1 M. Caller must not assume
  45 // capacity without checking.
  46 void LogStream::LineBuffer::try_ensure_cap(size_t atleast) {
  47   assert(_cap >= sizeof(_smallbuf), "sanity");
  48   if (_cap < atleast) {
  49     // Cap out at a reasonable max to prevent runaway leaks.
  50     const size_t reasonable_max = 1 * M;
  51     assert(_cap <= reasonable_max, "sanity");
  52     if (_cap == reasonable_max) {
  53       return;
  54     }
  55 
  56     const size_t additional_expansion = 256;
  57     size_t newcap = align_up(atleast + additional_expansion, additional_expansion);
  58     if (newcap > reasonable_max) {
  59       log_info(logging)("Suspiciously long log line: \"%.100s%s",
  60               _buf, (_pos >= 100 ? "..." : ""));
  61       newcap = reasonable_max;
  62     }
  63 
  64     char* const newbuf = (char*) os::malloc(newcap, mtLogging);
  65     if (newbuf == NULL) { // OOM. Leave object unchanged.
  66       return;
  67     }
  68     if (_pos > 0) { // preserve old content
  69       memcpy(newbuf, _buf, _pos + 1); // ..including trailing zero
  70     }
  71     if (_buf != _smallbuf) {
  72       os::free(_buf);
  73     }
  74     _buf = newbuf;
  75     _cap = newcap;
  76   }
  77   assert(_cap >= atleast, "sanity");
  78 }
  79 
  80 void LogStream::LineBuffer::append(const char* s, size_t len) {
  81   assert(_buf[_pos] == '\0', "sanity");
  82   assert(_pos < _cap, "sanity");
  83   const size_t minimum_capacity_needed = _pos + len + 1;
  84   try_ensure_cap(minimum_capacity_needed);
  85   // try_ensure_cap may not have enlarged the capacity to the full requested
  86   // extend or may have not worked at all. In that case, just gracefully work
  87   // with what we have already; just truncate if necessary.
  88   if (_cap < minimum_capacity_needed) {
  89     len = _cap - _pos - 1;
  90     if (len == 0) {
  91       return;
  92     }
  93   }
  94   memcpy(_buf + _pos, s, len);
  95   _pos += len;
  96   _buf[_pos] = '\0';
  97 }
  98 
  99 void LogStream::LineBuffer::reset() {
 100   _pos = 0;
 101   _buf[_pos] = '\0';
 102 }
 103 
 104 void LogStream::write(const char* s, size_t len) {
 105   if (len > 0 && s[len - 1] == '\n') {
 106     _current_line.append(s, len - 1); // omit the newline.
 107     _log_handle.print("%s", _current_line.buffer());
 108     _current_line.reset();
 109   } else {
 110     _current_line.append(s, len);
 111   }
 112   update_position(s, len);
 113 }
 114