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// Copyright (c) 2010 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "base/vlog.h"
#include <stddef.h>
#include <algorithm>
#include <limits>
#include <ostream>
#include <utility>
#include "base/logging.h"
#include "base/strings/string_number_conversions.h"
#include "base/strings/string_split.h"
#include "base/strings/string_util.h"
namespace logging {
const int VlogInfo::kDefaultVlogLevel = 0;
struct VlogInfo::VmodulePattern {
enum MatchTarget { MATCH_MODULE, MATCH_FILE };
explicit VmodulePattern(const std::string& pattern);
VmodulePattern() = default;
std::string pattern;
int vlog_level = VlogInfo::kDefaultVlogLevel;
MatchTarget match_target = MATCH_MODULE;
size_t score = 0;
};
VlogInfo::VmodulePattern::VmodulePattern(const std::string& pattern)
: pattern(pattern) {
// If the pattern contains a {forward,back} slash, we assume that
// it's meant to be tested against the entire __FILE__ string.
std::string::size_type first_slash = pattern.find_first_of("\\/");
if (first_slash != std::string::npos)
match_target = MATCH_FILE;
}
VlogInfo::VlogInfo(const std::string& v_switch,
const std::string& vmodule_switch,
int* min_log_level)
: min_log_level_(min_log_level) {
DCHECK_NE(min_log_level, nullptr);
int vlog_level = 0;
if (!v_switch.empty()) {
if (base::StringToInt(v_switch, &vlog_level)) {
SetMaxVlogLevel(vlog_level);
} else {
DLOG(WARNING) << "Could not parse v switch \"" << v_switch << "\"";
}
}
base::StringPairs kv_pairs;
if (!base::SplitStringIntoKeyValuePairs(
vmodule_switch, '=', ',', &kv_pairs)) {
DLOG(WARNING) << "Could not fully parse vmodule switch \""
<< vmodule_switch << "\"";
}
for (base::StringPairs::const_iterator it = kv_pairs.begin();
it != kv_pairs.end(); ++it) {
VmodulePattern pattern(it->first);
if (!base::StringToInt(it->second, &pattern.vlog_level)) {
DLOG(WARNING) << "Parsed vlog level for \""
<< it->first << "=" << it->second
<< "\" as " << pattern.vlog_level;
}
vmodule_levels_.push_back(pattern);
}
}
VlogInfo::~VlogInfo() = default;
namespace {
// Given a path, returns the basename with the extension chopped off
// (and any -inl suffix). We avoid using FilePath to minimize the
// number of dependencies the logging system has.
base::StringPiece GetModule(base::StringPiece file) {
base::StringPiece module = file;
// Chop off the file extension.
base::StringPiece::size_type extension_start = module.rfind('.');
module = module.substr(0, extension_start);
// Chop off the -inl suffix.
static constexpr base::StringPiece kInlSuffix("-inl");
if (base::EndsWith(module, kInlSuffix))
module.remove_suffix(kInlSuffix.size());
// Chop off the path up to the start of the file name. Using single-character
// overload of `base::StringPiece::find_last_of` for speed; this overload does
// not build a lookup table.
base::StringPiece::size_type last_slash_pos = module.find_last_of('/');
if (last_slash_pos != base::StringPiece::npos) {
module.remove_prefix(last_slash_pos + 1);
return module;
}
last_slash_pos = module.find_last_of('\\');
if (last_slash_pos != base::StringPiece::npos)
module.remove_prefix(last_slash_pos + 1);
return module;
}
} // namespace
int VlogInfo::GetVlogLevel(base::StringPiece file) {
base::AutoLock lock(vmodule_levels_lock_);
if (!vmodule_levels_.empty()) {
base::StringPiece module(GetModule(file));
for (size_t i = 0; i < vmodule_levels_.size(); i++) {
VmodulePattern& it = vmodule_levels_[i];
const bool kUseFile = it.match_target == VmodulePattern::MATCH_FILE;
if (!MatchVlogPattern(kUseFile ? file : module, it.pattern)) {
continue;
}
const int ret = it.vlog_level;
// Since `it` matched, increase its score because we believe it has a
// higher probability of winning next time.
if (it.score == std::numeric_limits<size_t>::max()) {
for (VmodulePattern& pattern : vmodule_levels_) {
pattern.score = 0;
}
}
++it.score;
if (i > 0 && it.score > vmodule_levels_[i - 1].score)
std::swap(it, vmodule_levels_[i - 1]);
return ret;
}
}
return GetMaxVlogLevel();
}
void VlogInfo::SetMaxVlogLevel(int level) {
// Log severity is the negative verbosity.
*min_log_level_ = -level;
}
int VlogInfo::GetMaxVlogLevel() const {
return -*min_log_level_;
}
bool MatchVlogPattern(base::StringPiece string,
base::StringPiece vlog_pattern) {
// The code implements the glob matching using a greedy approach described in
// https://research.swtch.com/glob.
size_t s = 0, nexts = 0;
size_t p = 0, nextp = 0;
const size_t slen = string.size(), plen = vlog_pattern.size();
while (s < slen || p < plen) {
if (p < plen) {
switch (vlog_pattern[p]) {
// A slash (forward or back) must match a slash (forward or back).
case '/':
case '\\':
if (s < slen && (string[s] == '/' || string[s] == '\\')) {
p++, s++;
continue;
}
break;
// A '?' matches anything.
case '?':
if (s < slen) {
p++, s++;
continue;
}
break;
case '*':
nextp = p;
nexts = s + 1;
p++;
continue;
// Anything else must match literally.
default:
if (s < slen && string[s] == vlog_pattern[p]) {
p++, s++;
continue;
}
break;
}
}
// Mismatch - maybe restart.
if (0 < nexts && nexts <= slen) {
p = nextp;
s = nexts;
continue;
}
return false;
}
return true;
}
} // namespace logging