I don't know how to change that.
I had an issue w/ the main routine ending before some of the worker
routines were done so I saw incomplete results.
How do I tweak my logic so that I don't need a WaitGroup?
I forgot about my platform specific code. Here is the rest of that, that
is in a file to be compiled on windows.
package main
import (
"fmt"
"os"
"path/filepath"
"strings"
) // Glob is case sensitive. I want case insensitive.
const estimatedNumberOfFiles = 100
func globCommandLineFiles(patterns []string) []string {
matchingNames := make([]string, 0, estimatedNumberOfFiles)
for _, pattern := range patterns {
matches, err := filepath.Glob(pattern) // Glob returns names of all
files matching the case-sensitive pattern.
if err != nil {
fmt.Fprintln(os.Stderr, " Error from filepath.Glob is", err)
os.Exit(1)
} else if matches != nil { // At least one match
matchingNames = append(matchingNames, matches...)
}
}
return matchingNames
}
func commandLineFiles(patterns []string) []string {
workingDirname, err := os.Getwd()
if err != nil {
fmt.Fprintln(os.Stderr, "from commandlinefiles:", err)
return nil
}
dirEntries, e := os.ReadDir(workingDirname) // became available as of
Go 1.16
if e != nil {
return nil
}
matchingNames := make([]string, 0, len(dirEntries))
for _, pattern := range patterns { // outer loop to test against
multiple patterns.
for _, d := range dirEntries { // inner loop to test each pattern
against the filenames.
if d.IsDir() {
continue // skip a subdirectory name
}
boolean, er := filepath.Match(pattern,
strings.ToLower(d.Name()))
if er != nil {
fmt.Fprintln(os.Stderr, er)
continue
}
if boolean {
matchingNames = append(matchingNames, d.Name())
}
}
}
return matchingNames
}
On Sunday, October 2, 2022 at 3:20:22 PM UTC-4 harr...@spu.edu wrote:
> I think Matthew is correct about the immediate source of the deadlock -
> because the defer is placed too late in the body of grepFile(), the
> deferred decrement of the waitGroup isn't run on an os.Open() error.
>
> I had the same impression as Jan, I think there is a concern here: the
> condition for closing grepChan could be, when all files have been sent into
> the channel. Currently, it's when all work is done. The difference is that
> one pattern is to increment/decrement waitGroup per unit of work, but
> another one is to increment/decrement just workers. For the latter, the
> worker decrements when it infers there is no more work to be done, i.e. it
> reads that grepChan has closed. I think changing the pattern would avoid
> the deadlock because, then, there's no reason to interact with the
> waitGroup per file.
>
> On Sunday, October 2, 2022 at 11:59:26 AM UTC-7 Jan Mercl wrote:
>
>> On Sun, Oct 2, 2022 at 8:52 PM rob <drro...@gmail.com> wrote:
>>
>> > When I do that, I get this error:
>> >
>> > panic: sync: negative WaitGroup number
>>
>> I tried to investigate, but the code does not build.
>>
>> ./main.go:99:11: undefined: globCommandLineFiles
>> ./main.go:101:11: undefined: commandLineFiles
>>
>> Can you please make it a self-contained, minimal program that
>> reproduces the failure?
>>
>
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