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trace: Frontend for reading trace-buffer entries

This commit is contained in:
Norman Feske 2013-09-15 17:27:06 +02:00
parent 31d2730c9a
commit 20883c52b5
1 changed files with 44 additions and 8 deletions
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52
base/include/base/trace/buffer.h
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@ -31,15 +31,15 @@ class Genode::Trace::Buffer
unsigned volatile _head_offset; /* in bytes, relative to 'entries' */
unsigned volatile _size; /* in bytes */
struct Entry
struct _Entry
{
size_t len;
char data[0];
};
Entry _entries[0];
_Entry _entries[0];
Entry *_head_entry() { return (Entry *)((addr_t)_entries + _head_offset); }
_Entry *_head_entry() { return (_Entry *)((addr_t)_entries + _head_offset); }
/*
* The 'entries' member marks the beginning of the trace buffer
@ -64,11 +64,13 @@ class Genode::Trace::Buffer
char *reserve(size_t len)
{
if (_head_offset + sizeof(Entry) + len <= _size)
if (_head_offset + sizeof(_Entry) + len <= _size)
return _head_entry()->data;
/* mark last entry with len 0 and wrap */
_head_entry()->len = 0;
if (_head_offset + sizeof(_Entry) <= _size)
_head_entry()->len = 0;
_head_offset = 0;
return _head_entry()->data;
@ -83,7 +85,7 @@ class Genode::Trace::Buffer
_head_entry()->len = len;
/* advance head offset, wrap when reaching buffer boundary */
_head_offset += sizeof(Entry) + len;
_head_offset += sizeof(_Entry) + len;
if (_head_offset == _size)
_head_offset = 0;
}
@ -93,8 +95,42 @@ class Genode::Trace::Buffer
** Functions called from the TRACE client **
********************************************/
addr_t entries() const { return (addr_t)_entries; }
addr_t head_offset() const { return (addr_t)_head_offset; }
class Entry
{
private:
_Entry const *_entry;
friend class Buffer;
Entry(_Entry const *entry) : _entry(entry) { }
public:
size_t length() const { return _entry->len; }
char const *data() const { return _entry->data; }
bool is_last() const { return _entry == 0; }
};
Entry first() const
{
return _entries->len ? Entry(_entries) : Entry(0);
}
Entry next(Entry entry) const
{
if (entry.is_last())
return Entry(0);
if (entry.length() == 0)
return Entry(0);
addr_t const offset = (addr_t)entry._entry - (addr_t)_entries;
if (offset + entry.length() + sizeof(_Entry) > _size)
return Entry(0);
return Entry((_Entry const *)((addr_t)entry.data() + entry.length()));
}
};
#endif /* _INCLUDE__BASE__TRACE__BUFFER_H_ */