| // 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. |
| // |
| // With -format=plain, the oracle prints query results to the standard |
| // output in an editor-friendly format in which every line of output |
| // is of the form "pos: text", where pos = "-" if unknown. |
| // |
| // With -format=json, the oracle prints structured data in JSON syntax. |
| // |
| package main |
| |
| import ( |
| "bufio" |
| "bytes" |
| "encoding/json" |
| "flag" |
| "fmt" |
| "go/build" |
| "io" |
| "log" |
| "os" |
| "runtime" |
| "runtime/pprof" |
| |
| "code.google.com/p/go.tools/importer" |
| "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 modeFlag = flag.String("mode", "", |
| "Mode of query to perform: e.g. callers, describe, etc.") |
| |
| 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: 'plain' or 'json'.") |
| |
| const usage = `Go source code oracle. |
| Usage: oracle [<flag> ...] <args> ... |
| Use -help flag to display options. |
| |
| The -mode flag is required; the -pos flag is required in most modes. |
| |
| Examples: |
| |
| Describe the syntax at offset 532 in this file (an import spec): |
| % oracle -mode=describe -pos=src/code.google.com/p/go.tools/cmd/oracle/main.go:#532 \ |
| code.google.com/p/go.tools/cmd/oracle |
| |
| Print the callgraph of the trivial web-server in JSON format: |
| % oracle -mode=callgraph -format=json src/pkg/net/http/triv.go |
| |
| ` + importer.InitialPackagesUsage |
| |
| 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 main() { |
| flag.Parse() |
| args := flag.Args() |
| |
| if len(args) == 0 { |
| fmt.Fprint(os.Stderr, usage) |
| os.Exit(1) |
| } |
| |
| // Set up points-to analysis log file. |
| var ptalog io.Writer |
| if *ptalogFlag != "" { |
| if f, err := os.Create(*ptalogFlag); err != nil { |
| log.Fatal(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 |
| if *formatFlag != "json" && *formatFlag != "plain" { |
| fmt.Fprintf(os.Stderr, "Error: illegal -format value: %q", *formatFlag) |
| os.Exit(1) |
| } |
| |
| // Ask the oracle. |
| res, err := oracle.Query(args, *modeFlag, *posFlag, ptalog, &build.Default) |
| if err != nil { |
| fmt.Fprintf(os.Stderr, "%s\n", err) |
| os.Exit(1) |
| } |
| |
| // Print the result. |
| switch *formatFlag { |
| case "json": |
| b, err := json.Marshal(res) |
| if err != nil { |
| fmt.Fprintf(os.Stderr, "JSON error: %s\n", err) |
| os.Exit(1) |
| } |
| var buf bytes.Buffer |
| if err := json.Indent(&buf, b, "", "\t"); err != nil { |
| fmt.Fprintf(os.Stderr, "json.Indent failed: %s", err) |
| os.Exit(1) |
| } |
| os.Stdout.Write(buf.Bytes()) |
| |
| case "plain": |
| res.WriteTo(os.Stdout) |
| } |
| } |