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[/] [openrisc/] [trunk/] [gnu-dev/] [or1k-gcc/] [libgo/] [go/] [exp/] [types/] [exportdata.go] - Blame information for rev 747

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// Copyright 2011 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.
 
// This file implements ExportData.
 
package types
 
import (
        "bufio"
        "errors"
        "fmt"
        "io"
        "os"
        "strconv"
        "strings"
)
 
func readGopackHeader(buf *bufio.Reader) (name string, size int, err error) {
        // See $GOROOT/include/ar.h.
        hdr := make([]byte, 16+12+6+6+8+10+2)
        _, err = io.ReadFull(buf, hdr)
        if err != nil {
                return
        }
        if trace {
                fmt.Printf("header: %s", hdr)
        }
        s := strings.TrimSpace(string(hdr[16+12+6+6+8:][:10]))
        size, err = strconv.Atoi(s)
        if err != nil || hdr[len(hdr)-2] != '`' || hdr[len(hdr)-1] != '\n' {
                err = errors.New("invalid archive header")
                return
        }
        name = strings.TrimSpace(string(hdr[:16]))
        return
}
 
type dataReader struct {
        *bufio.Reader
        io.Closer
}
 
// ExportData returns a readCloser positioned at the beginning of the
// export data section of the given object/archive file, or an error.
// It is the caller's responsibility to close the readCloser.
//
func ExportData(filename string) (rc io.ReadCloser, err error) {
        file, err := os.Open(filename)
        if err != nil {
                return
        }
 
        defer func() {
                if err != nil {
                        file.Close()
                        // Add file name to error.
                        err = fmt.Errorf("reading export data: %s: %v", filename, err)
                }
        }()
 
        buf := bufio.NewReader(file)
 
        // Read first line to make sure this is an object file.
        line, err := buf.ReadSlice('\n')
        if err != nil {
                return
        }
        if string(line) == "!\n" {
                // Archive file.  Scan to __.PKGDEF, which should
                // be second archive entry.
                var name string
                var size int
 
                // First entry should be __.SYMDEF.
                // Read and discard.
                if name, size, err = readGopackHeader(buf); err != nil {
                        return
                }
                if name != "__.SYMDEF" {
                        err = errors.New("go archive does not begin with __.SYMDEF")
                        return
                }
                const block = 4096
                tmp := make([]byte, block)
                for size > 0 {
                        n := size
                        if n > block {
                                n = block
                        }
                        _, err = io.ReadFull(buf, tmp[:n])
                        if err != nil {
                                return
                        }
                        size -= n
                }
 
                // Second entry should be __.PKGDEF.
                if name, size, err = readGopackHeader(buf); err != nil {
                        return
                }
                if name != "__.PKGDEF" {
                        err = errors.New("go archive is missing __.PKGDEF")
                        return
                }
 
                // Read first line of __.PKGDEF data, so that line
                // is once again the first line of the input.
                line, err = buf.ReadSlice('\n')
                if err != nil {
                        return
                }
        }
 
        // Now at __.PKGDEF in archive or still at beginning of file.
        // Either way, line should begin with "go object ".
        if !strings.HasPrefix(string(line), "go object ") {
                err = errors.New("not a go object file")
                return
        }
 
        // Skip over object header to export data.
        // Begins after first line with $$.
        for line[0] != '$' {
                line, err = buf.ReadSlice('\n')
                if err != nil {
                        return
                }
        }
 
        rc = &dataReader{buf, file}
        return
}

Line No.	Rev	Author	Line
1	747	jeremybenn	`// Copyright 2011 The Go Authors. All rights reserved.`
2			`// Use of this source code is governed by a BSD-style`
3			`// license that can be found in the LICENSE file.`
4
5			`// This file implements ExportData.`
6
7			`package types`
8
9			`import (`
10			`"bufio"`
11			`"errors"`
12			`"fmt"`
13			`"io"`
14			`"os"`
15			`"strconv"`
16			`"strings"`
17			`)`
18
19			`func readGopackHeader(buf *bufio.Reader) (name string, size int, err error) {`
20			`// See $GOROOT/include/ar.h.`
21			`hdr := make([]byte, 16+12+6+6+8+10+2)`
22			`_, err = io.ReadFull(buf, hdr)`
23			`if err != nil {`
24			`return`
25			`}`
26			`if trace {`
27			`fmt.Printf("header: %s", hdr)`
28			`}`
29			`s := strings.TrimSpace(string(hdr[16+12+6+6+8:][:10]))`
30			`size, err = strconv.Atoi(s)`
31			if err != nil \|\| hdr[len(hdr)-2] != '`' \|\| hdr[len(hdr)-1] != '\n' {
32			`err = errors.New("invalid archive header")`
33			`return`
34			`}`
35			`name = strings.TrimSpace(string(hdr[:16]))`
36			`return`
37			`}`
38
39			`type dataReader struct {`
40			`*bufio.Reader`
41			`io.Closer`
42			`}`
43
44			`// ExportData returns a readCloser positioned at the beginning of the`
45			`// export data section of the given object/archive file, or an error.`
46			`// It is the caller's responsibility to close the readCloser.`
47			`//`
48			`func ExportData(filename string) (rc io.ReadCloser, err error) {`
49			`file, err := os.Open(filename)`
50			`if err != nil {`
51			`return`
52			`}`
53
54			`defer func() {`
55			`if err != nil {`
56			`file.Close()`
57			`// Add file name to error.`
58			`err = fmt.Errorf("reading export data: %s: %v", filename, err)`
59			`}`
60			`}()`
61
62			`buf := bufio.NewReader(file)`
63
64			`// Read first line to make sure this is an object file.`
65			`line, err := buf.ReadSlice('\n')`
66			`if err != nil {`
67			`return`
68			`}`
69			`if string(line) == "!\n" {`
70			`// Archive file. Scan to __.PKGDEF, which should`
71			`// be second archive entry.`
72			`var name string`
73			`var size int`
74
75			`// First entry should be __.SYMDEF.`
76			`// Read and discard.`
77			`if name, size, err = readGopackHeader(buf); err != nil {`
78			`return`
79			`}`
80			`if name != "__.SYMDEF" {`
81			`err = errors.New("go archive does not begin with __.SYMDEF")`
82			`return`
83			`}`
84			`const block = 4096`
85			`tmp := make([]byte, block)`
86			`for size > 0 {`
87			`n := size`
88			`if n > block {`
89			`n = block`
90			`}`
91			`_, err = io.ReadFull(buf, tmp[:n])`
92			`if err != nil {`
93			`return`
94			`}`
95			`size -= n`
96			`}`
97
98			`// Second entry should be __.PKGDEF.`
99			`if name, size, err = readGopackHeader(buf); err != nil {`
100			`return`
101			`}`
102			`if name != "__.PKGDEF" {`
103			`err = errors.New("go archive is missing __.PKGDEF")`
104			`return`
105			`}`
106
107			`// Read first line of __.PKGDEF data, so that line`
108			`// is once again the first line of the input.`
109			`line, err = buf.ReadSlice('\n')`
110			`if err != nil {`
111			`return`
112			`}`
113			`}`
114
115			`// Now at __.PKGDEF in archive or still at beginning of file.`
116			`// Either way, line should begin with "go object ".`
117			`if !strings.HasPrefix(string(line), "go object ") {`
118			`err = errors.New("not a go object file")`
119			`return`
120			`}`
121
122			`// Skip over object header to export data.`
123			`// Begins after first line with $$.`
124			`for line[0] != '$' {`
125			`line, err = buf.ReadSlice('\n')`
126			`if err != nil {`
127			`return`
128			`}`
129			`}`
130
131			`rc = &dataReader{buf, file}`
132			`return`
133			`}`

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[/] [openrisc/] [trunk/] [gnu-dev/] [or1k-gcc/] [libgo/] [go/] [exp/] [types/] [exportdata.go] - Blame information for rev 747