diff options
Diffstat (limited to 'Godeps/_workspace/src/github.com/davecgh/go-spew/spew/dump.go')
-rw-r--r-- | Godeps/_workspace/src/github.com/davecgh/go-spew/spew/dump.go | 509 |
1 files changed, 509 insertions, 0 deletions
diff --git a/Godeps/_workspace/src/github.com/davecgh/go-spew/spew/dump.go b/Godeps/_workspace/src/github.com/davecgh/go-spew/spew/dump.go new file mode 100644 index 000000000..a0ff95e27 --- /dev/null +++ b/Godeps/_workspace/src/github.com/davecgh/go-spew/spew/dump.go @@ -0,0 +1,509 @@ +/* + * Copyright (c) 2013 Dave Collins <dave@davec.name> + * + * Permission to use, copy, modify, and distribute this software for any + * purpose with or without fee is hereby granted, provided that the above + * copyright notice and this permission notice appear in all copies. + * + * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES + * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF + * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR + * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES + * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN + * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF + * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. + */ + +package spew + +import ( + "bytes" + "encoding/hex" + "fmt" + "io" + "os" + "reflect" + "regexp" + "strconv" + "strings" +) + +var ( + // uint8Type is a reflect.Type representing a uint8. It is used to + // convert cgo types to uint8 slices for hexdumping. + uint8Type = reflect.TypeOf(uint8(0)) + + // cCharRE is a regular expression that matches a cgo char. + // It is used to detect character arrays to hexdump them. + cCharRE = regexp.MustCompile("^.*\\._Ctype_char$") + + // cUnsignedCharRE is a regular expression that matches a cgo unsigned + // char. It is used to detect unsigned character arrays to hexdump + // them. + cUnsignedCharRE = regexp.MustCompile("^.*\\._Ctype_unsignedchar$") + + // cUint8tCharRE is a regular expression that matches a cgo uint8_t. + // It is used to detect uint8_t arrays to hexdump them. + cUint8tCharRE = regexp.MustCompile("^.*\\._Ctype_uint8_t$") +) + +// dumpState contains information about the state of a dump operation. +type dumpState struct { + w io.Writer + depth int + pointers map[uintptr]int + ignoreNextType bool + ignoreNextIndent bool + cs *ConfigState +} + +// indent performs indentation according to the depth level and cs.Indent +// option. +func (d *dumpState) indent() { + if d.ignoreNextIndent { + d.ignoreNextIndent = false + return + } + d.w.Write(bytes.Repeat([]byte(d.cs.Indent), d.depth)) +} + +// unpackValue returns values inside of non-nil interfaces when possible. +// This is useful for data types like structs, arrays, slices, and maps which +// can contain varying types packed inside an interface. +func (d *dumpState) unpackValue(v reflect.Value) reflect.Value { + if v.Kind() == reflect.Interface && !v.IsNil() { + v = v.Elem() + } + return v +} + +// dumpPtr handles formatting of pointers by indirecting them as necessary. +func (d *dumpState) dumpPtr(v reflect.Value) { + // Remove pointers at or below the current depth from map used to detect + // circular refs. + for k, depth := range d.pointers { + if depth >= d.depth { + delete(d.pointers, k) + } + } + + // Keep list of all dereferenced pointers to show later. + pointerChain := make([]uintptr, 0) + + // Figure out how many levels of indirection there are by dereferencing + // pointers and unpacking interfaces down the chain while detecting circular + // references. + nilFound := false + cycleFound := false + indirects := 0 + ve := v + for ve.Kind() == reflect.Ptr { + if ve.IsNil() { + nilFound = true + break + } + indirects++ + addr := ve.Pointer() + pointerChain = append(pointerChain, addr) + if pd, ok := d.pointers[addr]; ok && pd < d.depth { + cycleFound = true + indirects-- + break + } + d.pointers[addr] = d.depth + + ve = ve.Elem() + if ve.Kind() == reflect.Interface { + if ve.IsNil() { + nilFound = true + break + } + ve = ve.Elem() + } + } + + // Display type information. + d.w.Write(openParenBytes) + d.w.Write(bytes.Repeat(asteriskBytes, indirects)) + d.w.Write([]byte(ve.Type().String())) + d.w.Write(closeParenBytes) + + // Display pointer information. + if len(pointerChain) > 0 { + d.w.Write(openParenBytes) + for i, addr := range pointerChain { + if i > 0 { + d.w.Write(pointerChainBytes) + } + printHexPtr(d.w, addr) + } + d.w.Write(closeParenBytes) + } + + // Display dereferenced value. + d.w.Write(openParenBytes) + switch { + case nilFound == true: + d.w.Write(nilAngleBytes) + + case cycleFound == true: + d.w.Write(circularBytes) + + default: + d.ignoreNextType = true + d.dump(ve) + } + d.w.Write(closeParenBytes) +} + +// dumpSlice handles formatting of arrays and slices. Byte (uint8 under +// reflection) arrays and slices are dumped in hexdump -C fashion. +func (d *dumpState) dumpSlice(v reflect.Value) { + // Determine whether this type should be hex dumped or not. Also, + // for types which should be hexdumped, try to use the underlying data + // first, then fall back to trying to convert them to a uint8 slice. + var buf []uint8 + doConvert := false + doHexDump := false + numEntries := v.Len() + if numEntries > 0 { + vt := v.Index(0).Type() + vts := vt.String() + switch { + // C types that need to be converted. + case cCharRE.MatchString(vts): + fallthrough + case cUnsignedCharRE.MatchString(vts): + fallthrough + case cUint8tCharRE.MatchString(vts): + doConvert = true + + // Try to use existing uint8 slices and fall back to converting + // and copying if that fails. + case vt.Kind() == reflect.Uint8: + // We need an addressable interface to convert the type + // to a byte slice. However, the reflect package won't + // give us an interface on certain things like + // unexported struct fields in order to enforce + // visibility rules. We use unsafe, when available, to + // bypass these restrictions since this package does not + // mutate the values. + vs := v + if !vs.CanInterface() || !vs.CanAddr() { + vs = unsafeReflectValue(vs) + } + if !UnsafeDisabled { + vs = vs.Slice(0, numEntries) + + // Use the existing uint8 slice if it can be + // type asserted. + iface := vs.Interface() + if slice, ok := iface.([]uint8); ok { + buf = slice + doHexDump = true + break + } + } + + // The underlying data needs to be converted if it can't + // be type asserted to a uint8 slice. + doConvert = true + } + + // Copy and convert the underlying type if needed. + if doConvert && vt.ConvertibleTo(uint8Type) { + // Convert and copy each element into a uint8 byte + // slice. + buf = make([]uint8, numEntries) + for i := 0; i < numEntries; i++ { + vv := v.Index(i) + buf[i] = uint8(vv.Convert(uint8Type).Uint()) + } + doHexDump = true + } + } + + // Hexdump the entire slice as needed. + if doHexDump { + indent := strings.Repeat(d.cs.Indent, d.depth) + str := indent + hex.Dump(buf) + str = strings.Replace(str, "\n", "\n"+indent, -1) + str = strings.TrimRight(str, d.cs.Indent) + d.w.Write([]byte(str)) + return + } + + // Recursively call dump for each item. + for i := 0; i < numEntries; i++ { + d.dump(d.unpackValue(v.Index(i))) + if i < (numEntries - 1) { + d.w.Write(commaNewlineBytes) + } else { + d.w.Write(newlineBytes) + } + } +} + +// dump is the main workhorse for dumping a value. It uses the passed reflect +// value to figure out what kind of object we are dealing with and formats it +// appropriately. It is a recursive function, however circular data structures +// are detected and handled properly. +func (d *dumpState) dump(v reflect.Value) { + // Handle invalid reflect values immediately. + kind := v.Kind() + if kind == reflect.Invalid { + d.w.Write(invalidAngleBytes) + return + } + + // Handle pointers specially. + if kind == reflect.Ptr { + d.indent() + d.dumpPtr(v) + return + } + + // Print type information unless already handled elsewhere. + if !d.ignoreNextType { + d.indent() + d.w.Write(openParenBytes) + d.w.Write([]byte(v.Type().String())) + d.w.Write(closeParenBytes) + d.w.Write(spaceBytes) + } + d.ignoreNextType = false + + // Display length and capacity if the built-in len and cap functions + // work with the value's kind and the len/cap itself is non-zero. + valueLen, valueCap := 0, 0 + switch v.Kind() { + case reflect.Array, reflect.Slice, reflect.Chan: + valueLen, valueCap = v.Len(), v.Cap() + case reflect.Map, reflect.String: + valueLen = v.Len() + } + if valueLen != 0 || valueCap != 0 { + d.w.Write(openParenBytes) + if valueLen != 0 { + d.w.Write(lenEqualsBytes) + printInt(d.w, int64(valueLen), 10) + } + if valueCap != 0 { + if valueLen != 0 { + d.w.Write(spaceBytes) + } + d.w.Write(capEqualsBytes) + printInt(d.w, int64(valueCap), 10) + } + d.w.Write(closeParenBytes) + d.w.Write(spaceBytes) + } + + // Call Stringer/error interfaces if they exist and the handle methods flag + // is enabled + if !d.cs.DisableMethods { + if (kind != reflect.Invalid) && (kind != reflect.Interface) { + if handled := handleMethods(d.cs, d.w, v); handled { + return + } + } + } + + switch kind { + case reflect.Invalid: + // Do nothing. We should never get here since invalid has already + // been handled above. + + case reflect.Bool: + printBool(d.w, v.Bool()) + + case reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64, reflect.Int: + printInt(d.w, v.Int(), 10) + + case reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uint: + printUint(d.w, v.Uint(), 10) + + case reflect.Float32: + printFloat(d.w, v.Float(), 32) + + case reflect.Float64: + printFloat(d.w, v.Float(), 64) + + case reflect.Complex64: + printComplex(d.w, v.Complex(), 32) + + case reflect.Complex128: + printComplex(d.w, v.Complex(), 64) + + case reflect.Slice: + if v.IsNil() { + d.w.Write(nilAngleBytes) + break + } + fallthrough + + case reflect.Array: + d.w.Write(openBraceNewlineBytes) + d.depth++ + if (d.cs.MaxDepth != 0) && (d.depth > d.cs.MaxDepth) { + d.indent() + d.w.Write(maxNewlineBytes) + } else { + d.dumpSlice(v) + } + d.depth-- + d.indent() + d.w.Write(closeBraceBytes) + + case reflect.String: + d.w.Write([]byte(strconv.Quote(v.String()))) + + case reflect.Interface: + // The only time we should get here is for nil interfaces due to + // unpackValue calls. + if v.IsNil() { + d.w.Write(nilAngleBytes) + } + + case reflect.Ptr: + // Do nothing. We should never get here since pointers have already + // been handled above. + + case reflect.Map: + // nil maps should be indicated as different than empty maps + if v.IsNil() { + d.w.Write(nilAngleBytes) + break + } + + d.w.Write(openBraceNewlineBytes) + d.depth++ + if (d.cs.MaxDepth != 0) && (d.depth > d.cs.MaxDepth) { + d.indent() + d.w.Write(maxNewlineBytes) + } else { + numEntries := v.Len() + keys := v.MapKeys() + if d.cs.SortKeys { + sortValues(keys, d.cs) + } + for i, key := range keys { + d.dump(d.unpackValue(key)) + d.w.Write(colonSpaceBytes) + d.ignoreNextIndent = true + d.dump(d.unpackValue(v.MapIndex(key))) + if i < (numEntries - 1) { + d.w.Write(commaNewlineBytes) + } else { + d.w.Write(newlineBytes) + } + } + } + d.depth-- + d.indent() + d.w.Write(closeBraceBytes) + + case reflect.Struct: + d.w.Write(openBraceNewlineBytes) + d.depth++ + if (d.cs.MaxDepth != 0) && (d.depth > d.cs.MaxDepth) { + d.indent() + d.w.Write(maxNewlineBytes) + } else { + vt := v.Type() + numFields := v.NumField() + for i := 0; i < numFields; i++ { + d.indent() + vtf := vt.Field(i) + d.w.Write([]byte(vtf.Name)) + d.w.Write(colonSpaceBytes) + d.ignoreNextIndent = true + d.dump(d.unpackValue(v.Field(i))) + if i < (numFields - 1) { + d.w.Write(commaNewlineBytes) + } else { + d.w.Write(newlineBytes) + } + } + } + d.depth-- + d.indent() + d.w.Write(closeBraceBytes) + + case reflect.Uintptr: + printHexPtr(d.w, uintptr(v.Uint())) + + case reflect.UnsafePointer, reflect.Chan, reflect.Func: + printHexPtr(d.w, v.Pointer()) + + // There were not any other types at the time this code was written, but + // fall back to letting the default fmt package handle it in case any new + // types are added. + default: + if v.CanInterface() { + fmt.Fprintf(d.w, "%v", v.Interface()) + } else { + fmt.Fprintf(d.w, "%v", v.String()) + } + } +} + +// fdump is a helper function to consolidate the logic from the various public +// methods which take varying writers and config states. +func fdump(cs *ConfigState, w io.Writer, a ...interface{}) { + for _, arg := range a { + if arg == nil { + w.Write(interfaceBytes) + w.Write(spaceBytes) + w.Write(nilAngleBytes) + w.Write(newlineBytes) + continue + } + + d := dumpState{w: w, cs: cs} + d.pointers = make(map[uintptr]int) + d.dump(reflect.ValueOf(arg)) + d.w.Write(newlineBytes) + } +} + +// Fdump formats and displays the passed arguments to io.Writer w. It formats +// exactly the same as Dump. +func Fdump(w io.Writer, a ...interface{}) { + fdump(&Config, w, a...) +} + +// Sdump returns a string with the passed arguments formatted exactly the same +// as Dump. +func Sdump(a ...interface{}) string { + var buf bytes.Buffer + fdump(&Config, &buf, a...) + return buf.String() +} + +/* +Dump displays the passed parameters to standard out with newlines, customizable +indentation, and additional debug information such as complete types and all +pointer addresses used to indirect to the final value. It provides the +following features over the built-in printing facilities provided by the fmt +package: + + * Pointers are dereferenced and followed + * Circular data structures are detected and handled properly + * Custom Stringer/error interfaces are optionally invoked, including + on unexported types + * Custom types which only implement the Stringer/error interfaces via + a pointer receiver are optionally invoked when passing non-pointer + variables + * Byte arrays and slices are dumped like the hexdump -C command which + includes offsets, byte values in hex, and ASCII output + +The configuration options are controlled by an exported package global, +spew.Config. See ConfigState for options documentation. + +See Fdump if you would prefer dumping to an arbitrary io.Writer or Sdump to +get the formatted result as a string. +*/ +func Dump(a ...interface{}) { + fdump(&Config, os.Stdout, a...) +} |