summary refs log tree commit diff stats
path: root/lib/system/deepcopy.nim
blob: 1f30b8427c03b7f26c2711f5550414a2c5dba34a (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
#
#
#            Nim's Runtime Library
#        (c) Copyright 2015 Andreas Rumpf
#
#    See the file "copying.txt", included in this
#    distribution, for details about the copyright.
#

const
  TableSize = when sizeof(int) <= 2: 0xff else: 0xff_ffff

type
  PtrTable = ptr object
    counter, max: int
    data: array[TableSize, (pointer, pointer)]

template hashPtr(key: pointer): int = cast[int](key) shr 8
template allocPtrTable: untyped =
  cast[PtrTable](alloc0(sizeof(int)*2 + sizeof(pointer)*2*cap))

proc rehash(t: PtrTable): PtrTable =
  let cap = (t.max+1) * 2
  result = allocPtrTable()
  result.counter = t.counter
  result.max = cap-1
  for i in 0..t.max:
    let k = t.data[i][0]
    if k != nil:
      var h = hashPtr(k)
      while result.data[h and result.max][0] != nil: inc h
      result.data[h and result.max] = t.data[i]
  dealloc t

proc initPtrTable(): PtrTable =
  const cap = 32
  result = allocPtrTable()
  result.counter = 0
  result.max = cap-1

template deinit(t: PtrTable) = dealloc(t)

proc get(t: PtrTable; key: pointer): pointer =
  var h = hashPtr(key)
  while true:
    let k = t.data[h and t.max][0]
    if k == nil: break
    if k == key:
      return t.data[h and t.max][1]
    inc h

proc put(t: var PtrTable; key, val: pointer) =
  if (t.max+1) * 2 < t.counter * 3: t = rehash(t)
  var h = hashPtr(key)
  while t.data[h and t.max][0] != nil: inc h
  t.data[h and t.max] = (key, val)
  inc t.counter

proc genericDeepCopyAux(dest, src: pointer, mt: PNimType;
                        tab: var PtrTable) {.benign.}
proc genericDeepCopyAux(dest, src: pointer, n: ptr TNimNode;
                        tab: var PtrTable) {.benign.} =
  var
    d = cast[ByteAddress](dest)
    s = cast[ByteAddress](src)
  case n.kind
  of nkSlot:
    genericDeepCopyAux(cast[pointer](d +% n.offset),
                       cast[pointer](s +% n.offset), n.typ, tab)
  of nkList:
    for i in 0..n.len-1:
      genericDeepCopyAux(dest, src, n.sons[i], tab)
  of nkCase:
    var dd = selectBranch(dest, n)
    var m = selectBranch(src, n)
    # reset if different branches are in use; note different branches also
    # imply that's not self-assignment (``x = x``)!
    if m != dd and dd != nil:
      genericResetAux(dest, dd)
    copyMem(cast[pointer](d +% n.offset), cast[pointer](s +% n.offset),
            n.typ.size)
    if m != nil:
      genericDeepCopyAux(dest, src, m, tab)
  of nkNone: sysAssert(false, "genericDeepCopyAux")

proc genericDeepCopyAux(dest, src: pointer, mt: PNimType; tab: var PtrTable) =
  var
    d = cast[ByteAddress](dest)
    s = cast[ByteAddress](src)
  sysAssert(mt != nil, "genericDeepCopyAux 2")
  case mt.kind
  of tyString:
    when defined(nimSeqsV2):
      var x = cast[ptr NimStringV2](dest)
      var s2 = cast[ptr NimStringV2](s)[]
      nimAsgnStrV2(x[], s2)
    else:
      var x = cast[PPointer](dest)
      var s2 = cast[PPointer](s)[]
      if s2 == nil:
        unsureAsgnRef(x, s2)
      else:
        unsureAsgnRef(x, copyDeepString(cast[NimString](s2)))
  of tySequence:
    when defined(nimSeqsV2):
      deepSeqAssignImpl(genericDeepCopyAux, tab)
    else:
      var s2 = cast[PPointer](src)[]
      var seq = cast[PGenericSeq](s2)
      var x = cast[PPointer](dest)
      if s2 == nil:
        unsureAsgnRef(x, s2)
        return
      sysAssert(dest != nil, "genericDeepCopyAux 3")
      unsureAsgnRef(x, newSeq(mt, seq.len))
      var dst = cast[ByteAddress](cast[PPointer](dest)[])
      for i in 0..seq.len-1:
        genericDeepCopyAux(
          cast[pointer](dst +% align(GenericSeqSize, mt.base.align) +% i *% mt.base.size),
          cast[pointer](cast[ByteAddress](s2) +% align(GenericSeqSize, mt.base.align) +% i *% mt.base.size),
          mt.base, tab)
  of tyObject:
    # we need to copy m_type field for tyObject, as it could be empty for
    # sequence reallocations:
    if mt.base != nil:
      genericDeepCopyAux(dest, src, mt.base, tab)
    else:
      var pint = cast[ptr PNimType](dest)
      pint[] = cast[ptr PNimType](src)[]
    genericDeepCopyAux(dest, src, mt.node, tab)
  of tyTuple:
    genericDeepCopyAux(dest, src, mt.node, tab)
  of tyArray, tyArrayConstr:
    for i in 0..(mt.size div mt.base.size)-1:
      genericDeepCopyAux(cast[pointer](d +% i *% mt.base.size),
                         cast[pointer](s +% i *% mt.base.size), mt.base, tab)
  of tyRef:
    let s2 = cast[PPointer](src)[]
    if s2 == nil:
      unsureAsgnRef(cast[PPointer](dest), s2)
    elif mt.base.deepcopy != nil:
      let z = mt.base.deepcopy(s2)
      when defined(nimSeqsV2):
        cast[PPointer](dest)[] = z
      else:
        unsureAsgnRef(cast[PPointer](dest), z)
    else:
      let z = tab.get(s2)
      if z == nil:
        when declared(usrToCell):
          let x = usrToCell(s2)
          let realType = x.typ
          let z = newObj(realType, realType.base.size)
          unsureAsgnRef(cast[PPointer](dest), z)
          tab.put(s2, z)
          genericDeepCopyAux(z, s2, realType.base, tab)
        else:
          when false:
            # addition check disabled
            let x = usrToCell(s2)
            let realType = x.typ
            sysAssert realType == mt, " types do differ"
          when defined(nimSeqsV2):
            let typ = if mt.base.kind == tyObject: cast[PNimType](cast[ptr PNimTypeV2](s2)[].typeInfoV1)
                      else: mt.base
            let z = nimNewObj(typ.size, typ.align)
            cast[PPointer](dest)[] = z
          else:
            # this version should work for any other GC:
            let typ = if mt.base.kind == tyObject: cast[ptr PNimType](s2)[] else: mt.base
            let z = newObj(mt, typ.size)
            unsureAsgnRef(cast[PPointer](dest), z)
          tab.put(s2, z)
          genericDeepCopyAux(z, s2, typ, tab)
      else:
        unsureAsgnRef(cast[PPointer](dest), z)
  of tyPtr:
    # no cycle check here, but also not really required
    let s2 = cast[PPointer](src)[]
    if s2 != nil and mt.base.deepcopy != nil:
      cast[PPointer](dest)[] = mt.base.deepcopy(s2)
    else:
      cast[PPointer](dest)[] = s2
  else:
    copyMem(dest, src, mt.size)

proc genericDeepCopy(dest, src: pointer, mt: PNimType) {.compilerproc.} =
  when not defined(nimSeqsV2): GC_disable()
  var tab = initPtrTable()
  genericDeepCopyAux(dest, src, mt, tab)
  deinit tab
  when not defined(nimSeqsV2): GC_enable()

proc genericSeqDeepCopy(dest, src: pointer, mt: PNimType) {.compilerproc.} =
  # also invoked for 'string'
  var src = src
  genericDeepCopy(dest, addr(src), mt)

proc genericDeepCopyOpenArray(dest, src: pointer, len: int,
                            mt: PNimType) {.compilerproc.} =
  var
    d = cast[ByteAddress](dest)
    s = cast[ByteAddress](src)
  for i in 0..len-1:
    genericDeepCopy(cast[pointer](d +% i *% mt.base.size),
                    cast[pointer](s +% i *% mt.base.size), mt.base)