Add front page of Fuzzer

fuzzer/go/fuzz/stacktrace.go

Index: fuzzer/go/fuzz/stacktrace.go
diff --git a/fuzzer/go/fuzz/stacktrace.go b/fuzzer/go/fuzz/stacktrace.go
new file mode 100644
index 0000000000000000000000000000000000000000..98a5887b7bfa81ac29c03072b8125a5274ec4404
--- /dev/null
+++ b/fuzzer/go/fuzz/stacktrace.go
@@ -0,0 +1,93 @@
+package fuzz
+
+import (
+	"bufio"
+	"bytes"
+	"fmt"
+	"regexp"
+	"strconv"
+	"strings"
+
+	"github.com/skia-dev/glog"
+)
+
+type StackTrace struct {
+	Frames []StackTraceFrame `json:"frames"`
+}
+
+type StackTraceFrame struct {
+	PackageName  string `json:"packageName"`
+	FileName     string `json:"fileName"`
+	LineNumber   int    `json:"lineNumber"`
+	FunctionName string `json:"functionName"`
+}
+
+// The `?:` at the beginning of the groups prevent them from being captured
+var stackTraceLine = regexp.MustCompile(`(?:\.\./)+((?:\w+/)+)(.+):(\d+)\(`)
+
+// Given the files of a dump file (created through get_stack_trace [which uses catchsegv], return the stack trace)
+func ParseStackTrace(contents string) StackTrace {
+	r := bytes.NewReader([]byte(contents))
+	scan := bufio.NewScanner(r)
+
+	hasBegun := false
+
+	frames := make([]StackTraceFrame, 0, 5)
+
+	for scan.Scan() {
+		line := scan.Text()
+		if strings.Contains(line, "Backtrace") {
+			hasBegun = true
+		}
+		if strings.Contains(line, "Memory map") {
+			break
+		}
+		if !hasBegun {
+			continue
+		}
+
+		if match := stackTraceLine.FindStringSubmatch(line); match != nil {
+			// match[0] is the entire matched portion, [1] is the "package", [2] is the file name, [3] is the line number
+
+			lineNumber, err := strconv.Atoi(match[3])
+			if err != nil {
+				glog.Errorf("Could not parse line number from stacktrace line %q: %s", match[0], err)
+				continue
+			}
+			newFrame := BasicStackFrame(match[1], match[2], lineNumber)
+			frames = append(frames, newFrame)
+		}
+	}
+
+	return StackTrace{frames}
+}
+
+func BasicStackFrame(packageName, fileName string, lineNumber int) StackTraceFrame {
+	return StackTraceFrame{packageName, fileName, lineNumber, ""}
+}
+
+type FindFunctionName func(packageName string, fileName string, lineNumber int) string
+
+// LookUpFunctions will go through all the stacktraces and call the passed in function to find the approximate function name the stacktrace is referring to
+func (st *StackTrace) LookUpFunctions(findFunctionName FindFunctionName) {
+	for i, f := range st.Frames {
+		// this awkward syntax is required to write to the actual StackTraceFrame, not the copy generated by range
+		st.Frames[i].FunctionName = findFunctionName(f.PackageName, f.FileName, f.LineNumber)
+	}
+}
+
+func (f *StackTraceFrame) String() string {
+	return fmt.Sprintf("%s%s:%d %s", f.PackageName, f.FileName, f.LineNumber, f.FunctionName)
+}
+
+func (st *StackTrace) String() string {
+	s := fmt.Sprintf("StackTrace with %d frames:\n", len(st.Frames))
+	for _, f := range st.Frames {
+		s += fmt.Sprintf("\t%s\n", f.String())
+	}
+	return s
+}
+
+func (st *StackTrace) IsEmpty() bool {
+	return len(st.Frames) == 0
+}