filter.go

     1  // Copyright 2014 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  // Implements methods to filter samples from profiles.
     6  
     7  package profile
     8  
     9  import "regexp"
    10  
    11  // FilterSamplesByName filters the samples in a profile and only keeps
    12  // samples where at least one frame matches focus but none match ignore.
    13  // Returns true is the corresponding regexp matched at least one sample.
    14  func (p *Profile) FilterSamplesByName(focus, ignore, hide *regexp.Regexp) (fm, im, hm bool) {
    15  	focusOrIgnore := make(map[uint64]bool)
    16  	hidden := make(map[uint64]bool)
    17  	for _, l := range p.Location {
    18  		if ignore != nil && l.matchesName(ignore) {
    19  			im = true
    20  			focusOrIgnore[l.ID] = false
    21  		} else if focus == nil || l.matchesName(focus) {
    22  			fm = true
    23  			focusOrIgnore[l.ID] = true
    24  		}
    25  		if hide != nil && l.matchesName(hide) {
    26  			hm = true
    27  			l.Line = l.unmatchedLines(hide)
    28  			if len(l.Line) == 0 {
    29  				hidden[l.ID] = true
    30  			}
    31  		}
    32  	}
    33  
    34  	s := make([]*Sample, 0, len(p.Sample))
    35  	for _, sample := range p.Sample {
    36  		if focusedAndNotIgnored(sample.Location, focusOrIgnore) {
    37  			if len(hidden) > 0 {
    38  				var locs []*Location
    39  				for _, loc := range sample.Location {
    40  					if !hidden[loc.ID] {
    41  						locs = append(locs, loc)
    42  					}
    43  				}
    44  				if len(locs) == 0 {
    45  					// Remove sample with no locations (by not adding it to s).
    46  					continue
    47  				}
    48  				sample.Location = locs
    49  			}
    50  			s = append(s, sample)
    51  		}
    52  	}
    53  	p.Sample = s
    54  
    55  	return
    56  }
    57  
    58  // matchesName reports whether the function name or file in the
    59  // location matches the regular expression.
    60  func (loc *Location) matchesName(re *regexp.Regexp) bool {
    61  	for _, ln := range loc.Line {
    62  		if fn := ln.Function; fn != nil {
    63  			if re.MatchString(fn.Name) {
    64  				return true
    65  			}
    66  			if re.MatchString(fn.Filename) {
    67  				return true
    68  			}
    69  		}
    70  	}
    71  	return false
    72  }
    73  
    74  // unmatchedLines returns the lines in the location that do not match
    75  // the regular expression.
    76  func (loc *Location) unmatchedLines(re *regexp.Regexp) []Line {
    77  	var lines []Line
    78  	for _, ln := range loc.Line {
    79  		if fn := ln.Function; fn != nil {
    80  			if re.MatchString(fn.Name) {
    81  				continue
    82  			}
    83  			if re.MatchString(fn.Filename) {
    84  				continue
    85  			}
    86  		}
    87  		lines = append(lines, ln)
    88  	}
    89  	return lines
    90  }
    91  
    92  // focusedAndNotIgnored looks up a slice of ids against a map of
    93  // focused/ignored locations. The map only contains locations that are
    94  // explicitly focused or ignored. Returns whether there is at least
    95  // one focused location but no ignored locations.
    96  func focusedAndNotIgnored(locs []*Location, m map[uint64]bool) bool {
    97  	var f bool
    98  	for _, loc := range locs {
    99  		if focus, focusOrIgnore := m[loc.ID]; focusOrIgnore {
   100  			if focus {
   101  				// Found focused location. Must keep searching in case there
   102  				// is an ignored one as well.
   103  				f = true
   104  			} else {
   105  				// Found ignored location. Can return false right away.
   106  				return false
   107  			}
   108  		}
   109  	}
   110  	return f
   111  }
   112  
   113  // TagMatch selects tags for filtering
   114  type TagMatch func(key, val string, nval int64) bool
   115  
   116  // FilterSamplesByTag removes all samples from the profile, except
   117  // those that match focus and do not match the ignore regular
   118  // expression.
   119  func (p *Profile) FilterSamplesByTag(focus, ignore TagMatch) (fm, im bool) {
   120  	samples := make([]*Sample, 0, len(p.Sample))
   121  	for _, s := range p.Sample {
   122  		focused, ignored := focusedSample(s, focus, ignore)
   123  		fm = fm || focused
   124  		im = im || ignored
   125  		if focused && !ignored {
   126  			samples = append(samples, s)
   127  		}
   128  	}
   129  	p.Sample = samples
   130  	return
   131  }
   132  
   133  // focusedTag checks a sample against focus and ignore regexps.
   134  // Returns whether the focus/ignore regexps match any tags
   135  func focusedSample(s *Sample, focus, ignore TagMatch) (fm, im bool) {
   136  	fm = focus == nil
   137  	for key, vals := range s.Label {
   138  		for _, val := range vals {
   139  			if ignore != nil && ignore(key, val, 0) {
   140  				im = true
   141  			}
   142  			if !fm && focus(key, val, 0) {
   143  				fm = true
   144  			}
   145  		}
   146  	}
   147  	for key, vals := range s.NumLabel {
   148  		for _, val := range vals {
   149  			if ignore != nil && ignore(key, "", val) {
   150  				im = true
   151  			}
   152  			if !fm && focus(key, "", val) {
   153  				fm = true
   154  			}
   155  		}
   156  	}
   157  	return fm, im
   158  }
   159
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