126 lines
3.7 KiB
Go
126 lines
3.7 KiB
Go
// Copyright (c) 2019 Uber Technologies, Inc.
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//
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// Permission is hereby granted, free of charge, to any person obtaining a copy
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// of this software and associated documentation files (the "Software"), to deal
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// in the Software without restriction, including without limitation the rights
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// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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// copies of the Software, and to permit persons to whom the Software is
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// furnished to do so, subject to the following conditions:
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//
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// The above copyright notice and this permission notice shall be included in
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// all copies or substantial portions of the Software.
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//
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// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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// THE SOFTWARE.
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package digreflect
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import (
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"fmt"
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"net/url"
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"reflect"
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"runtime"
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"strings"
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)
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// Func contains runtime information about a function.
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type Func struct {
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// Name of the function.
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Name string
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// Name of the package in which this function is defined.
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Package string
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// Path to the file in which this function is defined.
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File string
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// Line number in the file at which this function is defined.
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Line int
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}
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// String returns a string representation of the function.
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func (f *Func) String() string {
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return fmt.Sprint(f)
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}
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// Format implements fmt.Formatter for Func, printing a single-line
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// representation for %v and a multi-line one for %+v.
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func (f *Func) Format(w fmt.State, c rune) {
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if w.Flag('+') && c == 'v' {
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// "path/to/package".MyFunction
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// path/to/file.go:42
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fmt.Fprintf(w, "%q.%v", f.Package, f.Name)
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fmt.Fprintf(w, "\n\t%v:%v", f.File, f.Line)
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} else {
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// "path/to/package".MyFunction (path/to/file.go:42)
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fmt.Fprintf(w, "%q.%v (%v:%v)", f.Package, f.Name, f.File, f.Line)
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}
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}
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// InspectFunc inspects and returns runtime information about the given
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// function.
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func InspectFunc(function interface{}) *Func {
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fptr := reflect.ValueOf(function).Pointer()
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return InspectFuncPC(fptr)
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}
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// InspectFuncPC inspects and returns runtime information about the function
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// at the given program counter address.
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func InspectFuncPC(pc uintptr) *Func {
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f := runtime.FuncForPC(pc)
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if f == nil {
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return nil
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}
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pkgName, funcName := splitFuncName(f.Name())
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fileName, lineNum := f.FileLine(pc)
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return &Func{
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Name: funcName,
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Package: pkgName,
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File: fileName,
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Line: lineNum,
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}
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}
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const _vendor = "/vendor/"
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func splitFuncName(function string) (pname string, fname string) {
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if len(function) == 0 {
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return
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}
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// We have something like "path.to/my/pkg.MyFunction". If the function is
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// a closure, it is something like, "path.to/my/pkg.MyFunction.func1".
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idx := 0
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// Everything up to the first "." after the last "/" is the package name.
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// Everything after the "." is the full function name.
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if i := strings.LastIndex(function, "/"); i >= 0 {
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idx = i
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}
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if i := strings.Index(function[idx:], "."); i >= 0 {
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idx += i
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}
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pname, fname = function[:idx], function[idx+1:]
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// The package may be vendored.
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if i := strings.Index(pname, _vendor); i > 0 {
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pname = pname[i+len(_vendor):]
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}
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// Package names are URL-encoded to avoid ambiguity in the case where the
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// package name contains ".git". Otherwise, "foo/bar.git.MyFunction" would
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// mean that "git" is the top-level function and "MyFunction" is embedded
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// inside it.
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if unescaped, err := url.QueryUnescape(pname); err == nil {
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pname = unescaped
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}
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return
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}
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