Roland Conybeare
f4e5261a72
This is because xputc() only *might* be called. ostream may update streambuf's buffer without calling streambuf virtual methods
384 lines
15 KiB
C++
384 lines
15 KiB
C++
/* @file log_streambuf.hpp */
|
|
|
|
#pragma once
|
|
|
|
#include "print/quoted_char.hpp"
|
|
#include <iostream>
|
|
#include <vector>
|
|
#include <cstring> // e.g. for std::memcpy()
|
|
#include <cstdint>
|
|
#include <cassert>
|
|
|
|
namespace xo {
|
|
/** recycling buffer for logging and pretty-printing
|
|
* - write to self-extending storage array
|
|
* - track position relative to start of line
|
|
**/
|
|
template <typename CharT, typename Traits = std::char_traits<CharT>>
|
|
class log_streambuf : public std::streambuf {
|
|
public:
|
|
struct rewind_state {
|
|
explicit rewind_state(std::size_t solpos, std::size_t color_esc, std::uint32_t p)
|
|
: solpos{solpos}, color_escape_chars{color_esc}, pos{p} {}
|
|
|
|
std::size_t solpos = 0;
|
|
std::size_t color_escape_chars = 0;
|
|
std::uint32_t pos = 0;
|
|
};
|
|
|
|
public:
|
|
log_streambuf(std::uint32_t buf_z, bool debug_flag = false) : debug_flag_{debug_flag} {
|
|
this->buf_v_.resize(buf_z);
|
|
this->reset_stream();
|
|
} /*ctor*/
|
|
|
|
std::streamsize capacity() const { return this->buf_v_.size(); }
|
|
const char * lo() const { return this->pbase(); }
|
|
const char * hi() const { return this->lo() + this->capacity(); }
|
|
std::uint32_t pos() const { return this->pptr() - this->pbase(); }
|
|
|
|
/** output position (relative to pbase) when local state last computed. Exposed here for unit tests **/
|
|
const char * _local_ppos() const { return local_ppos_; }
|
|
/** position (relative to pbase) one character after last \n or \r. For unit tests **/
|
|
std::uint32_t _solpos() const { return solpos_; }
|
|
/** start of incomplete color-escape sequence **/
|
|
const char * _color_escape_start() const { return color_escape_start_; }
|
|
/** number of non-printing chars after @ref solpos_ from completed color-escape sequences **/
|
|
std::uint32_t _color_escape_chars() const { return color_escape_chars_; }
|
|
|
|
/** number of visible characters since start of line (last \n or \r) **/
|
|
std::uint32_t lpos() const {
|
|
if (debug_flag_) {
|
|
std::cerr << "log_streambuf::lpos: enter" << std::endl;
|
|
}
|
|
|
|
// logically-const. lazy implementation
|
|
log_streambuf * self = const_cast<log_streambuf *>(this);
|
|
|
|
self->_check_update_local_state();
|
|
|
|
return pos() - solpos_ - color_escape_chars_;
|
|
}
|
|
|
|
rewind_state checkpoint() const {
|
|
// logically-const. lazy implementation
|
|
log_streambuf * self = const_cast<log_streambuf *>(this);
|
|
|
|
self->_check_update_local_state();
|
|
|
|
return rewind_state(solpos_, color_escape_chars_, pos());
|
|
}
|
|
|
|
bool debug_flag() const { return debug_flag_; }
|
|
|
|
void reset_stream() {
|
|
char * p_lo = &(this->buf_v_[0]);
|
|
char * p_hi = p_lo + this->capacity();
|
|
|
|
/* tells parent our buffer extent */
|
|
this->setp(p_lo, p_hi);
|
|
|
|
this->local_ppos_ = 0;
|
|
this->solpos_ = 0;
|
|
this->color_escape_chars_ = 0;
|
|
this->color_escape_start_ = nullptr;
|
|
} /*reset_stream*/
|
|
|
|
void rewind_to(rewind_state s) {
|
|
if (debug_flag_) {
|
|
std::cout << "rewind_to: pos " << pos() << "->" << s.pos
|
|
<< " solpos " << solpos_ << "->" << s.solpos
|
|
<< " color_esc " << color_escape_chars_ << "->" << s.color_escape_chars
|
|
<< std::endl;
|
|
}
|
|
|
|
/* .setp(): using just for side effect: sets .pptr to .pbase */
|
|
this->setp(this->pbase(), this->epptr());
|
|
/* advance pptr to saved position */
|
|
this->pbump(s.pos);
|
|
|
|
this->local_ppos_ = this->pptr() - this->pbase();
|
|
this->solpos_ = s.solpos;
|
|
this->color_escape_chars_ = s.color_escape_chars;
|
|
/* assuming we never try to capture rewind state with incomplete color escape */
|
|
this->color_escape_start_ = nullptr;
|
|
}
|
|
|
|
protected:
|
|
/** expand buffer storage (by 2x), preserve current contents **/
|
|
void
|
|
expand_to(std::size_t new_z) {
|
|
char * old_pptr = pptr();
|
|
std::streamsize old_n = old_pptr - pbase();
|
|
|
|
assert(old_n <= static_cast<std::streamsize>(buf_v_.size()));
|
|
assert(new_z > buf_v_.capacity());
|
|
|
|
/* note: local_ppos_ invariant across expand_to() */
|
|
|
|
this->buf_v_.resize(new_z);
|
|
|
|
char * p_base = &(this->buf_v_[0]);
|
|
char * p_hi = p_base + this->buf_v_.capacity();
|
|
|
|
this->setp(p_base, p_hi);
|
|
this->pbump(old_n);
|
|
}
|
|
|
|
virtual std::streamsize
|
|
xsputn(char const * s, std::streamsize n) override {
|
|
/* s must be an address in [this->lo() .. this->lo() + capacity()] */
|
|
|
|
assert(hi() >= pptr());
|
|
|
|
if (pptr() + n > hi()) {
|
|
this->expand_to(std::max(2 * this->buf_v_.capacity(), std::size_t(this->pos() + n + 1)));
|
|
}
|
|
|
|
if (debug_flag_) {
|
|
std::cout << "xsputn: pbase=" << (void *)(this->pbase())
|
|
<< ", pptr=" << (void*)(this->pptr())
|
|
<< "(+" << (this->pptr() - this->lo()) << ")"
|
|
<< ", n=" << n << " -> (+" << (this->pptr() + n - this->lo()) << ")"
|
|
<< ", buf_v.size=" << this->buf_v_.size()
|
|
<< std::endl;
|
|
}
|
|
|
|
std::streamsize ncopied = 0;
|
|
|
|
if (this->pptr() + n > this->hi()) {
|
|
ncopied = this->hi() - this->pptr();
|
|
} else {
|
|
ncopied = n;
|
|
}
|
|
|
|
if (false /*debug_flag_*/) {
|
|
std::cout << "xsputn: copying ncopied=" << ncopied << " (/n=" << n << ") bytes into range [lo,hi)"
|
|
<< ", lo=" << (void*)this->pptr()
|
|
<< ", hi=" << (void*)(this->pptr() + n)
|
|
<< std::endl;
|
|
}
|
|
|
|
std::memcpy(this->pptr(), s, ncopied);
|
|
|
|
this->pbump(ncopied);
|
|
|
|
/* now {pbase, pptr} consistent with new input */
|
|
|
|
this->_check_update_local_state();
|
|
|
|
return ncopied;
|
|
} /*xsputn*/
|
|
|
|
virtual int_type
|
|
overflow(int_type new_ch) override {
|
|
char * old_base = this->pbase();
|
|
char * old_pptr = this->pptr();
|
|
/* #of chars buffered */
|
|
std::streamsize old_n = old_pptr - old_base;
|
|
|
|
assert(old_n <= static_cast<std::streamsize>(this->buf_v_.size()));
|
|
|
|
if (debug_flag_) {
|
|
std::cout << "overflow: new_ch=" << quoted_char(new_ch) << std::endl;
|
|
}
|
|
|
|
/* increase buffer size */
|
|
this->expand_to(2 * buf_v_.size());
|
|
|
|
this->buf_v_[old_n] = new_ch;
|
|
this->pbump(1);
|
|
|
|
if ((new_ch == static_cast<int_type>('\n')) || (new_ch == static_cast<int_type>('\r'))) {
|
|
this->solpos_ = this->pos();
|
|
|
|
// what if new_ch starts color escape ?
|
|
}
|
|
|
|
if (new_ch == Traits::eof()) {
|
|
/* reminder: returning eof sets badbit on ostream */
|
|
return Traits::not_eof(new_ch);
|
|
} else {
|
|
return new_ch;
|
|
}
|
|
} /*overflow*/
|
|
|
|
/* off. offset, relative to starting point dir.
|
|
* dir.
|
|
* which. in|out|both
|
|
*
|
|
* Note that off=0,dir=cur,which=out reads offset
|
|
*/
|
|
virtual pos_type seekoff(off_type off,
|
|
std::ios_base::seekdir dir,
|
|
std::ios_base::openmode which) override {
|
|
//std::cout << "seekoff: off=" << off << ", dir=" << dir << ", which=" << which << std::endl;
|
|
if (debug_flag_) {
|
|
std::cout << "seekoff(off,dir,which)" << std::endl;
|
|
}
|
|
|
|
// Only output stream is supported
|
|
if (which != std::ios_base::out)
|
|
throw std::runtime_error("log_streambuf: only output mode supported");
|
|
|
|
if (dir == std::ios_base::cur) {
|
|
this->pbump(off);
|
|
} else if (dir == std::ios_base::end) {
|
|
/* .setp(): using for side effect: sets .pptr to .pbase */
|
|
this->setp(this->pbase(), this->epptr());
|
|
this->pbump(off);
|
|
} else if (dir == std::ios_base::beg) {
|
|
/* .setp(): using for side effect: sets .pptr to .pbase */
|
|
this->setp(this->pbase(), this->epptr());
|
|
this->pbump(this->capacity() + off);
|
|
}
|
|
|
|
return this->pptr() - this->pbase();
|
|
} /*seekoff*/
|
|
|
|
private:
|
|
void _update_local_state_char(const char * p_lo, const char * p)
|
|
{
|
|
if ((*p == '\n') || (*p == '\r')) {
|
|
this->solpos_ = (p+1 - this->pbase());
|
|
/* reset, since these chars relevant as correction to solpos */
|
|
this->color_escape_chars_ = 0;
|
|
/* -> incomplete color escape, broken by newline */
|
|
this->color_escape_start_ = nullptr;
|
|
} else if (*p == '\033') {
|
|
if (debug_flag_) [[unlikely]] {
|
|
std::cout << "xsputn: \\033 at p-p_lo=" << (p - p_lo) << std::endl;
|
|
}
|
|
this->color_escape_start_ = p;
|
|
} else if (this->color_escape_start_ != nullptr) {
|
|
if (*p == 'm') {
|
|
/* escape seq non-printing including both endpoints */
|
|
std::int64_t esc_chars = (p+1 - color_escape_start_);
|
|
|
|
this->color_escape_chars_ += esc_chars;
|
|
|
|
if (debug_flag_) [[unlikely]] {
|
|
std::cout << "xsputn: m at p-p_lo" << (p - p_lo) << " +" << esc_chars
|
|
<< " -> color_escape_chars=" << color_escape_chars_ << std::endl;
|
|
}
|
|
this->color_escape_start_ = nullptr;
|
|
} else if (!isdigit(*p) && (*p != '[') && (*p != ';')) {
|
|
/* not color escape after all */
|
|
this->color_escape_start_ = nullptr;
|
|
}
|
|
}
|
|
}
|
|
|
|
/** recognize stale local state vars:
|
|
* @ref solpos_, @ref color_escape_chars_, @ref color_escape_start_.
|
|
*
|
|
* Require:
|
|
* - {pbase, pptr} in consistent state
|
|
* Promise:
|
|
* - @c local_ppos_ + @c pbase = @c pptr
|
|
* - @c solpos_, @c color_escape_chars_, @c color_escape_start_ all up-to-date
|
|
**/
|
|
void _check_update_local_state() {
|
|
const char * p0 = this->pbase();
|
|
const char * pn = this->pptr();
|
|
|
|
if (debug_flag_) {
|
|
std::cerr << "_check_update_local_state:" << std::endl;
|
|
std::cerr << " buf: (p0=" << (void*)p0 << ", pn=" << (void*)pn << ")" << std::endl;
|
|
std::cerr << " solpos_=" << solpos_ << ", color_escape_chars_=" << color_escape_chars_ << std::endl;
|
|
}
|
|
|
|
if (p0 + local_ppos_ == pn) [[likely]] {
|
|
// solpos_, color_escape_chars_, color_escape_start_ all up-to-date
|
|
} else {
|
|
// [pnew, pn): input that hasn't been incorporated into
|
|
// {solpos_, color_escape_chars_, color_escape_start_)
|
|
|
|
const char * pnew = this->pbase() + this->local_ppos_;
|
|
|
|
if (debug_flag_) {
|
|
std::cerr << "_check_update_local_state: range: (pnew=" << (void*)pnew << ", pn=" << (void*)pn << ")" << std::endl;
|
|
}
|
|
|
|
for(const char * p = pnew; p < pn; ++p) {
|
|
this->_update_local_state_char(p0, p);
|
|
}
|
|
}
|
|
|
|
// solpos_, color_escape_chars_, color_escape_start_ all up-to-date
|
|
// for current buffered contents
|
|
|
|
this->local_ppos_ = pn - p0;
|
|
|
|
if (debug_flag_) {
|
|
std::cerr << "_check_update_local_state: pos=" << pos();
|
|
std::cerr << ", solpos=" << solpos_;
|
|
std::cerr << ", color_escape_chars=" << color_escape_chars_ << std::endl;
|
|
}
|
|
|
|
assert(pos() >= solpos_ + color_escape_chars_);
|
|
}
|
|
|
|
private:
|
|
/*
|
|
* pbase: start of buffered text. Thils will be address of buf_v_[0]
|
|
*
|
|
*
|
|
* pbase pptr epptr
|
|
* v >e1< >e2< v v
|
|
* |xx\xxEEExxx\xxxxxxxEExxxxEExxxxxxxEExxx\xEExxxxxx..................|
|
|
* ^ ^<------new------->
|
|
* solpos local_ppos
|
|
*
|
|
* solpos : first character after newline (stale)
|
|
* color_escape_pos : e1+e2+.. (stale)
|
|
* new : new characters not reflected
|
|
* in local_ppos_, color_escape_chars_ etc.
|
|
*
|
|
* Legend:
|
|
* [\] newline
|
|
* [x] visible character
|
|
* [E] color escape chars
|
|
*
|
|
*
|
|
* after _check_update_local_state():
|
|
*
|
|
*
|
|
* pbase pptr epptr
|
|
* v >e1< v v
|
|
* |xx\xxEEExxx\xxxxxxxEExxxxEExxxxxxxEExxx\xEExxxxxx..................|
|
|
* ^ ^
|
|
* solpos local_ppos
|
|
*
|
|
*/
|
|
|
|
/** @defgroup logstreambuf-instance-vars **/
|
|
///@{
|
|
|
|
/** value of pptr (relative to pbase) when _check_update_local_state() last ran **/
|
|
std::size_t local_ppos_ = 0;
|
|
/** position (relative to pbase) one character after last \n or \r.
|
|
* Use to drive @ref lpos. This _has_ to be lazy, since
|
|
* xsputn() isn'g guaranteed to be called when there's room in
|
|
* in buffer.
|
|
**/
|
|
std::size_t solpos_ = 0;
|
|
/** number of non-printing chars after @ref solpos_, from
|
|
* completed color escape sequences.
|
|
* (ansi color escapes = text between '\033' and 'm')
|
|
**/
|
|
std::size_t color_escape_chars_ = 0;
|
|
/** non-null: start of incomplete color escape sequence **/
|
|
const char * color_escape_start_ = nullptr;
|
|
|
|
/** buffered output stored here **/
|
|
std::vector<char> buf_v_;
|
|
/** true to debug log_streambuf itself **/
|
|
bool debug_flag_ = false;
|
|
|
|
///@}
|
|
}; /*log_streambuf*/
|
|
|
|
} /*namespace xo*/
|
|
|
|
/* end log_streambuf.hpp */
|