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// Copyright 2013 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.
// oracle: a tool for answering questions about Go source code.
// http://golang.org/s/oracle-design
// http://golang.org/s/oracle-user-manual
//
// Run with -help flag or help subcommand for usage information.
//
package main
import (
"bufio"
"encoding/json"
"encoding/xml"
"flag"
"fmt"
"go/build"
"io"
"log"
"os"
"runtime"
"runtime/pprof"
"code.google.com/p/go.tools/go/loader"
"code.google.com/p/go.tools/oracle"
)
var posFlag = flag.String("pos", "",
"Filename and byte offset or extent of a syntax element about which to query, "+
"e.g. foo.go:#123,#456, bar.go:#123.")
var ptalogFlag = flag.String("ptalog", "",
"Location of the points-to analysis log file, or empty to disable logging.")
var formatFlag = flag.String("format", "plain", "Output format. One of {plain,json,xml}.")
// TODO(adonovan): flip this flag after PTA presolver is implemented.
var reflectFlag = flag.Bool("reflect", false, "Analyze reflection soundly (slow).")
const useHelp = "Run 'oracle -help' for more information.\n"
const helpMessage = `Go source code oracle.
Usage: oracle [<flag> ...] <mode> <args> ...
The -format flag controls the output format:
plain an editor-friendly format in which every line of output
is of the form "pos: text", where pos is "-" if unknown.
json structured data in JSON syntax.
xml structured data in XML syntax.
The -pos flag is required in all modes except 'callgraph'.
The mode argument determines the query to perform:
callees show possible targets of selected function call
callers show possible callers of selected function
callgraph show complete callgraph of program
callstack show path from callgraph root to selected function
describe describe selected syntax: definition, methods, etc
freevars show free variables of selection
implements show 'implements' relation for selected package
peers show send/receive corresponding to selected channel op
referrers show all refs to entity denoted by selected identifier
The user manual is available here: http://golang.org/s/oracle-user-manual
Examples:
Describe the syntax at offset 530 in this file (an import spec):
% oracle -pos=src/code.google.com/p/go.tools/cmd/oracle/main.go:#530 describe \
code.google.com/p/go.tools/cmd/oracle
Print the callgraph of the trivial web-server in JSON format:
% oracle -format=json src/pkg/net/http/triv.go callgraph
` + loader.FromArgsUsage
var cpuprofile = flag.String("cpuprofile", "", "write cpu profile to file")
func init() {
// If $GOMAXPROCS isn't set, use the full capacity of the machine.
// For small machines, use at least 4 threads.
if os.Getenv("GOMAXPROCS") == "" {
n := runtime.NumCPU()
if n < 4 {
n = 4
}
runtime.GOMAXPROCS(n)
}
}
func printHelp() {
fmt.Fprintln(os.Stderr, helpMessage)
fmt.Fprintln(os.Stderr, "Flags:")
flag.PrintDefaults()
}
func main() {
// Don't print full help unless -help was requested.
// Just gently remind users that it's there.
flag.Usage = func() { fmt.Fprint(os.Stderr, useHelp) }
flag.CommandLine.Init(os.Args[0], flag.ContinueOnError) // hack
if err := flag.CommandLine.Parse(os.Args[1:]); err != nil {
// (err has already been printed)
if err == flag.ErrHelp {
printHelp()
}
os.Exit(2)
}
args := flag.Args()
if len(args) == 0 || args[0] == "" {
fmt.Fprint(os.Stderr, "Error: a mode argument is required.\n"+useHelp)
os.Exit(2)
}
mode := args[0]
args = args[1:]
if mode == "help" {
printHelp()
os.Exit(2)
}
if len(args) == 0 && mode != "what" {
fmt.Fprint(os.Stderr, "Error: no package arguments.\n"+useHelp)
os.Exit(2)
}
// Set up points-to analysis log file.
var ptalog io.Writer
if *ptalogFlag != "" {
if f, err := os.Create(*ptalogFlag); err != nil {
log.Fatalf("Failed to create PTA log file: %s", err)
} else {
buf := bufio.NewWriter(f)
ptalog = buf
defer func() {
buf.Flush()
f.Close()
}()
}
}
// Profiling support.
if *cpuprofile != "" {
f, err := os.Create(*cpuprofile)
if err != nil {
log.Fatal(err)
}
pprof.StartCPUProfile(f)
defer pprof.StopCPUProfile()
}
// -format flag
switch *formatFlag {
case "json", "plain", "xml":
// ok
default:
fmt.Fprintf(os.Stderr, "Error: illegal -format value: %q.\n"+useHelp, *formatFlag)
os.Exit(2)
}
// Ask the oracle.
res, err := oracle.Query(args, mode, *posFlag, ptalog, &build.Default, *reflectFlag)
if err != nil {
fmt.Fprintf(os.Stderr, "Error: %s.\n", err)
os.Exit(1)
}
// Print the result.
switch *formatFlag {
case "json":
b, err := json.MarshalIndent(res.Serial(), "", "\t")
if err != nil {
fmt.Fprintf(os.Stderr, "JSON error: %s.\n", err)
os.Exit(1)
}
os.Stdout.Write(b)
case "xml":
b, err := xml.MarshalIndent(res.Serial(), "", "\t")
if err != nil {
fmt.Fprintf(os.Stderr, "XML error: %s.\n", err)
os.Exit(1)
}
os.Stdout.Write(b)
case "plain":
res.WriteTo(os.Stdout)
}
}
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