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// Copyright 2022 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package cformat
// This package provides apis for producing human-readable summaries
// of coverage data (e.g. a coverage percentage for a given package or
// set of packages) and for writing data in the legacy test format
// emitted by "go test -coverprofile=<outfile>".
//
// The model for using these apis is to create a Formatter object,
// then make a series of calls to SetPackage and AddUnit passing in
// data read from coverage meta-data and counter-data files. E.g.
//
// myformatter := cformat.NewFormatter()
// ...
// for each package P in meta-data file: {
// myformatter.SetPackage(P)
// for each function F in P: {
// for each coverable unit U in F: {
// myformatter.AddUnit(U)
// }
// }
// }
// myformatter.EmitPercent(os.Stdout, "", true, true)
// myformatter.EmitTextual(somefile)
//
// These apis are linked into tests that are built with "-cover", and
// called at the end of test execution to produce text output or
// emit coverage percentages.
import (
"fmt"
"internal/coverage"
"internal/coverage/cmerge"
"io"
"sort"
"text/tabwriter"
)
type Formatter struct {
// Maps import path to package state.
pm map[string]*pstate
// Records current package being visited.
pkg string
// Pointer to current package state.
p *pstate
// Counter mode.
cm coverage.CounterMode
}
// pstate records package-level coverage data state:
// - a table of functions (file/fname/literal)
// - a map recording the index/ID of each func encountered so far
// - a table storing execution count for the coverable units in each func
type pstate struct {
// slice of unique functions
funcs []fnfile
// maps function to index in slice above (index acts as function ID)
funcTable map[fnfile]uint32
// A table storing coverage counts for each coverable unit.
unitTable map[extcu]uint32
}
// extcu encapsulates a coverable unit within some function.
type extcu struct {
fnfid uint32 // index into p.funcs slice
coverage.CoverableUnit
}
// fnfile is a function-name/file-name tuple.
type fnfile struct {
file string
fname string
lit bool
}
func NewFormatter(cm coverage.CounterMode) *Formatter {
return &Formatter{
pm: make(map[string]*pstate),
cm: cm,
}
}
// SetPackage tells the formatter that we're about to visit the
// coverage data for the package with the specified import path.
// Note that it's OK to call SetPackage more than once with the
// same import path; counter data values will be accumulated.
func (fm *Formatter) SetPackage(importpath string) {
if importpath == fm.pkg {
return
}
fm.pkg = importpath
ps, ok := fm.pm[importpath]
if !ok {
ps = new(pstate)
fm.pm[importpath] = ps
ps.unitTable = make(map[extcu]uint32)
ps.funcTable = make(map[fnfile]uint32)
}
fm.p = ps
}
// AddUnit passes info on a single coverable unit (file, funcname,
// literal flag, range of lines, and counter value) to the formatter.
// Counter values will be accumulated where appropriate.
func (fm *Formatter) AddUnit(file string, fname string, isfnlit bool, unit coverage.CoverableUnit, count uint32) {
if fm.p == nil {
panic("AddUnit invoked before SetPackage")
}
fkey := fnfile{file: file, fname: fname, lit: isfnlit}
idx, ok := fm.p.funcTable[fkey]
if !ok {
idx = uint32(len(fm.p.funcs))
fm.p.funcs = append(fm.p.funcs, fkey)
fm.p.funcTable[fkey] = idx
}
ukey := extcu{fnfid: idx, CoverableUnit: unit}
pcount := fm.p.unitTable[ukey]
var result uint32
if fm.cm == coverage.CtrModeSet {
if count != 0 || pcount != 0 {
result = 1
}
} else {
// Use saturating arithmetic.
result, _ = cmerge.SaturatingAdd(pcount, count)
}
fm.p.unitTable[ukey] = result
}
// sortUnits sorts a slice of extcu objects in a package according to
// source position information (e.g. file and line). Note that we don't
// include function name as part of the sorting criteria, the thinking
// being that is better to provide things in the original source order.
func (p *pstate) sortUnits(units []extcu) {
sort.Slice(units, func(i, j int) bool {
ui := units[i]
uj := units[j]
ifile := p.funcs[ui.fnfid].file
jfile := p.funcs[uj.fnfid].file
if ifile != jfile {
return ifile < jfile
}
// NB: not taking function literal flag into account here (no
// need, since other fields are guaranteed to be distinct).
if units[i].StLine != units[j].StLine {
return units[i].StLine < units[j].StLine
}
if units[i].EnLine != units[j].EnLine {
return units[i].EnLine < units[j].EnLine
}
if units[i].StCol != units[j].StCol {
return units[i].StCol < units[j].StCol
}
if units[i].EnCol != units[j].EnCol {
return units[i].EnCol < units[j].EnCol
}
return units[i].NxStmts < units[j].NxStmts
})
}
// EmitTextual writes the accumulated coverage data in the legacy
// cmd/cover text format to the writer 'w'. We sort the data items by
// importpath, source file, and line number before emitting (this sorting
// is not explicitly mandated by the format, but seems like a good idea
// for repeatable/deterministic dumps).
func (fm *Formatter) EmitTextual(w io.Writer) error {
if fm.cm == coverage.CtrModeInvalid {
panic("internal error, counter mode unset")
}
if _, err := fmt.Fprintf(w, "mode: %s\n", fm.cm.String()); err != nil {
return err
}
pkgs := make([]string, 0, len(fm.pm))
for importpath := range fm.pm {
pkgs = append(pkgs, importpath)
}
sort.Strings(pkgs)
for _, importpath := range pkgs {
p := fm.pm[importpath]
units := make([]extcu, 0, len(p.unitTable))
for u := range p.unitTable {
units = append(units, u)
}
p.sortUnits(units)
for _, u := range units {
count := p.unitTable[u]
file := p.funcs[u.fnfid].file
if _, err := fmt.Fprintf(w, "%s:%d.%d,%d.%d %d %d\n",
file, u.StLine, u.StCol,
u.EnLine, u.EnCol, u.NxStmts, count); err != nil {
return err
}
}
}
return nil
}
// EmitPercent writes out a "percentage covered" string to the writer 'w'.
func (fm *Formatter) EmitPercent(w io.Writer, covpkgs string, noteEmpty bool, aggregate bool) error {
pkgs := make([]string, 0, len(fm.pm))
for importpath := range fm.pm {
pkgs = append(pkgs, importpath)
}
rep := func(cov, tot uint64) error {
if tot != 0 {
if _, err := fmt.Fprintf(w, "coverage: %.1f%% of statements%s\n",
100.0*float64(cov)/float64(tot), covpkgs); err != nil {
return err
}
} else if noteEmpty {
if _, err := fmt.Fprintf(w, "coverage: [no statements]\n"); err != nil {
return err
}
}
return nil
}
sort.Strings(pkgs)
var totalStmts, coveredStmts uint64
for _, importpath := range pkgs {
p := fm.pm[importpath]
if !aggregate {
totalStmts, coveredStmts = 0, 0
}
for unit, count := range p.unitTable {
nx := uint64(unit.NxStmts)
totalStmts += nx
if count != 0 {
coveredStmts += nx
}
}
if !aggregate {
if _, err := fmt.Fprintf(w, "\t%s\t\t", importpath); err != nil {
return err
}
if err := rep(coveredStmts, totalStmts); err != nil {
return err
}
}
}
if aggregate {
if err := rep(coveredStmts, totalStmts); err != nil {
return err
}
}
return nil
}
// EmitFuncs writes out a function-level summary to the writer 'w'. A
// note on handling function literals: although we collect coverage
// data for unnamed literals, it probably does not make sense to
// include them in the function summary since there isn't any good way
// to name them (this is also consistent with the legacy cmd/cover
// implementation). We do want to include their counts in the overall
// summary however.
func (fm *Formatter) EmitFuncs(w io.Writer) error {
if fm.cm == coverage.CtrModeInvalid {
panic("internal error, counter mode unset")
}
perc := func(covered, total uint64) float64 {
if total == 0 {
total = 1
}
return 100.0 * float64(covered) / float64(total)
}
tabber := tabwriter.NewWriter(w, 1, 8, 1, '\t', 0)
defer tabber.Flush()
allStmts := uint64(0)
covStmts := uint64(0)
pkgs := make([]string, 0, len(fm.pm))
for importpath := range fm.pm {
pkgs = append(pkgs, importpath)
}
sort.Strings(pkgs)
// Emit functions for each package, sorted by import path.
for _, importpath := range pkgs {
p := fm.pm[importpath]
if len(p.unitTable) == 0 {
continue
}
units := make([]extcu, 0, len(p.unitTable))
for u := range p.unitTable {
units = append(units, u)
}
// Within a package, sort the units, then walk through the
// sorted array. Each time we hit a new function, emit the
// summary entry for the previous function, then make one last
// emit call at the end of the loop.
p.sortUnits(units)
fname := ""
ffile := ""
flit := false
var fline uint32
var cstmts, tstmts uint64
captureFuncStart := func(u extcu) {
fname = p.funcs[u.fnfid].fname
ffile = p.funcs[u.fnfid].file
flit = p.funcs[u.fnfid].lit
fline = u.StLine
}
emitFunc := func(u extcu) error {
// Don't emit entries for function literals (see discussion
// in function header comment above).
if !flit {
if _, err := fmt.Fprintf(tabber, "%s:%d:\t%s\t%.1f%%\n",
ffile, fline, fname, perc(cstmts, tstmts)); err != nil {
return err
}
}
captureFuncStart(u)
allStmts += tstmts
covStmts += cstmts
tstmts = 0
cstmts = 0
return nil
}
for k, u := range units {
if k == 0 {
captureFuncStart(u)
} else {
if fname != p.funcs[u.fnfid].fname {
// New function; emit entry for previous one.
if err := emitFunc(u); err != nil {
return err
}
}
}
tstmts += uint64(u.NxStmts)
count := p.unitTable[u]
if count != 0 {
cstmts += uint64(u.NxStmts)
}
}
if err := emitFunc(extcu{}); err != nil {
return err
}
}
if _, err := fmt.Fprintf(tabber, "%s\t%s\t%.1f%%\n",
"total", "(statements)", perc(covStmts, allStmts)); err != nil {
return err
}
return nil
}