| /* |
| * |
| * Copyright 2015 gRPC authors. |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| * |
| */ |
| |
| #include <grpc/support/port_platform.h> |
| |
| #include <grpc/slice_buffer.h> |
| |
| #include <string.h> |
| |
| #include <grpc/support/alloc.h> |
| #include <grpc/support/log.h> |
| |
| #include "src/core/lib/gpr/useful.h" |
| #include "src/core/lib/iomgr/exec_ctx.h" |
| #include "src/core/lib/slice/slice_internal.h" |
| |
| /* grow a buffer; requires GRPC_SLICE_BUFFER_INLINE_ELEMENTS > 1 */ |
| #define GROW(x) (3 * (x) / 2) |
| |
| static void maybe_embiggen(grpc_slice_buffer* sb) { |
| /* How far away from sb->base_slices is sb->slices pointer */ |
| size_t slice_offset = static_cast<size_t>(sb->slices - sb->base_slices); |
| size_t slice_count = sb->count + slice_offset; |
| |
| if (slice_count == sb->capacity) { |
| if (sb->base_slices != sb->slices) { |
| /* Make room by moving elements if there's still space unused */ |
| memmove(sb->base_slices, sb->slices, sb->count * sizeof(grpc_slice)); |
| sb->slices = sb->base_slices; |
| } else { |
| /* Allocate more memory if no more space is available */ |
| sb->capacity = GROW(sb->capacity); |
| GPR_ASSERT(sb->capacity > slice_count); |
| if (sb->base_slices == sb->inlined) { |
| sb->base_slices = static_cast<grpc_slice*>( |
| gpr_malloc(sb->capacity * sizeof(grpc_slice))); |
| memcpy(sb->base_slices, sb->inlined, slice_count * sizeof(grpc_slice)); |
| } else { |
| sb->base_slices = static_cast<grpc_slice*>( |
| gpr_realloc(sb->base_slices, sb->capacity * sizeof(grpc_slice))); |
| } |
| |
| sb->slices = sb->base_slices + slice_offset; |
| } |
| } |
| } |
| |
| void grpc_slice_buffer_init(grpc_slice_buffer* sb) { |
| sb->count = 0; |
| sb->length = 0; |
| sb->capacity = GRPC_SLICE_BUFFER_INLINE_ELEMENTS; |
| sb->base_slices = sb->slices = sb->inlined; |
| } |
| |
| void grpc_slice_buffer_destroy_internal(grpc_slice_buffer* sb) { |
| grpc_slice_buffer_reset_and_unref_internal(sb); |
| if (sb->base_slices != sb->inlined) { |
| gpr_free(sb->base_slices); |
| } |
| } |
| |
| void grpc_slice_buffer_destroy(grpc_slice_buffer* sb) { |
| if (grpc_core::ExecCtx::Get() == nullptr) { |
| grpc_core::ExecCtx exec_ctx; |
| grpc_slice_buffer_destroy_internal(sb); |
| } else { |
| grpc_slice_buffer_destroy_internal(sb); |
| } |
| } |
| |
| uint8_t* grpc_slice_buffer_tiny_add(grpc_slice_buffer* sb, size_t n) { |
| grpc_slice* back; |
| uint8_t* out; |
| |
| sb->length += n; |
| |
| if (sb->count == 0) goto add_new; |
| back = &sb->slices[sb->count - 1]; |
| if (back->refcount) goto add_new; |
| if ((back->data.inlined.length + n) > sizeof(back->data.inlined.bytes)) |
| goto add_new; |
| out = back->data.inlined.bytes + back->data.inlined.length; |
| back->data.inlined.length = |
| static_cast<uint8_t>(back->data.inlined.length + n); |
| return out; |
| |
| add_new: |
| maybe_embiggen(sb); |
| back = &sb->slices[sb->count]; |
| sb->count++; |
| back->refcount = nullptr; |
| back->data.inlined.length = static_cast<uint8_t>(n); |
| return back->data.inlined.bytes; |
| } |
| |
| size_t grpc_slice_buffer_add_indexed(grpc_slice_buffer* sb, grpc_slice s) { |
| size_t out = sb->count; |
| maybe_embiggen(sb); |
| sb->slices[out] = s; |
| sb->length += GRPC_SLICE_LENGTH(s); |
| sb->count = out + 1; |
| return out; |
| } |
| |
| void grpc_slice_buffer_add(grpc_slice_buffer* sb, grpc_slice s) { |
| size_t n = sb->count; |
| /* if both the last slice in the slice buffer and the slice being added |
| are inlined (that is, that they carry their data inside the slice data |
| structure), and the back slice is not full, then concatenate directly |
| into the back slice, preventing many small slices being passed into |
| writes */ |
| if (!s.refcount && n) { |
| grpc_slice* back = &sb->slices[n - 1]; |
| if (!back->refcount && |
| back->data.inlined.length < GRPC_SLICE_INLINED_SIZE) { |
| if (s.data.inlined.length + back->data.inlined.length <= |
| GRPC_SLICE_INLINED_SIZE) { |
| memcpy(back->data.inlined.bytes + back->data.inlined.length, |
| s.data.inlined.bytes, s.data.inlined.length); |
| back->data.inlined.length = static_cast<uint8_t>( |
| back->data.inlined.length + s.data.inlined.length); |
| } else { |
| size_t cp1 = GRPC_SLICE_INLINED_SIZE - back->data.inlined.length; |
| memcpy(back->data.inlined.bytes + back->data.inlined.length, |
| s.data.inlined.bytes, cp1); |
| back->data.inlined.length = GRPC_SLICE_INLINED_SIZE; |
| maybe_embiggen(sb); |
| back = &sb->slices[n]; |
| sb->count = n + 1; |
| back->refcount = nullptr; |
| back->data.inlined.length = |
| static_cast<uint8_t>(s.data.inlined.length - cp1); |
| memcpy(back->data.inlined.bytes, s.data.inlined.bytes + cp1, |
| s.data.inlined.length - cp1); |
| } |
| sb->length += s.data.inlined.length; |
| return; /* early out */ |
| } |
| } |
| grpc_slice_buffer_add_indexed(sb, s); |
| } |
| |
| void grpc_slice_buffer_addn(grpc_slice_buffer* sb, grpc_slice* s, size_t n) { |
| size_t i; |
| for (i = 0; i < n; i++) { |
| grpc_slice_buffer_add(sb, s[i]); |
| } |
| } |
| |
| void grpc_slice_buffer_pop(grpc_slice_buffer* sb) { |
| if (sb->count != 0) { |
| size_t count = --sb->count; |
| sb->length -= GRPC_SLICE_LENGTH(sb->slices[count]); |
| } |
| } |
| |
| void grpc_slice_buffer_reset_and_unref_internal(grpc_slice_buffer* sb) { |
| size_t i; |
| for (i = 0; i < sb->count; i++) { |
| grpc_slice_unref_internal(sb->slices[i]); |
| } |
| |
| sb->count = 0; |
| sb->length = 0; |
| } |
| |
| void grpc_slice_buffer_reset_and_unref(grpc_slice_buffer* sb) { |
| if (grpc_core::ExecCtx::Get() == nullptr) { |
| grpc_core::ExecCtx exec_ctx; |
| grpc_slice_buffer_reset_and_unref_internal(sb); |
| } else { |
| grpc_slice_buffer_reset_and_unref_internal(sb); |
| } |
| } |
| |
| void grpc_slice_buffer_swap(grpc_slice_buffer* a, grpc_slice_buffer* b) { |
| size_t a_offset = static_cast<size_t>(a->slices - a->base_slices); |
| size_t b_offset = static_cast<size_t>(b->slices - b->base_slices); |
| |
| size_t a_count = a->count + a_offset; |
| size_t b_count = b->count + b_offset; |
| |
| if (a->base_slices == a->inlined) { |
| if (b->base_slices == b->inlined) { |
| /* swap contents of inlined buffer */ |
| grpc_slice temp[GRPC_SLICE_BUFFER_INLINE_ELEMENTS]; |
| memcpy(temp, a->base_slices, a_count * sizeof(grpc_slice)); |
| memcpy(a->base_slices, b->base_slices, b_count * sizeof(grpc_slice)); |
| memcpy(b->base_slices, temp, a_count * sizeof(grpc_slice)); |
| } else { |
| /* a is inlined, b is not - copy a inlined into b, fix pointers */ |
| a->base_slices = b->base_slices; |
| b->base_slices = b->inlined; |
| memcpy(b->base_slices, a->inlined, a_count * sizeof(grpc_slice)); |
| } |
| } else if (b->base_slices == b->inlined) { |
| /* b is inlined, a is not - copy b inlined int a, fix pointers */ |
| b->base_slices = a->base_slices; |
| a->base_slices = a->inlined; |
| memcpy(a->base_slices, b->inlined, b_count * sizeof(grpc_slice)); |
| } else { |
| /* no inlining: easy swap */ |
| GPR_SWAP(grpc_slice*, a->base_slices, b->base_slices); |
| } |
| |
| /* Update the slices pointers (cannot do a GPR_SWAP on slices fields here). |
| * Also note that since the base_slices pointers are already swapped we need |
| * use 'b_offset' for 'a->base_slices' and vice versa */ |
| a->slices = a->base_slices + b_offset; |
| b->slices = b->base_slices + a_offset; |
| |
| /* base_slices and slices fields are correctly set. Swap all other fields */ |
| GPR_SWAP(size_t, a->count, b->count); |
| GPR_SWAP(size_t, a->capacity, b->capacity); |
| GPR_SWAP(size_t, a->length, b->length); |
| } |
| |
| void grpc_slice_buffer_move_into(grpc_slice_buffer* src, |
| grpc_slice_buffer* dst) { |
| /* anything to move? */ |
| if (src->count == 0) { |
| return; |
| } |
| /* anything in dst? */ |
| if (dst->count == 0) { |
| grpc_slice_buffer_swap(src, dst); |
| return; |
| } |
| /* both buffers have data - copy, and reset src */ |
| grpc_slice_buffer_addn(dst, src->slices, src->count); |
| src->count = 0; |
| src->length = 0; |
| } |
| |
| static void slice_buffer_move_first_maybe_ref(grpc_slice_buffer* src, size_t n, |
| grpc_slice_buffer* dst, |
| bool incref) { |
| GPR_ASSERT(src->length >= n); |
| if (src->length == n) { |
| grpc_slice_buffer_move_into(src, dst); |
| return; |
| } |
| |
| size_t output_len = dst->length + n; |
| size_t new_input_len = src->length - n; |
| |
| while (src->count > 0) { |
| grpc_slice slice = grpc_slice_buffer_take_first(src); |
| size_t slice_len = GRPC_SLICE_LENGTH(slice); |
| if (n > slice_len) { |
| grpc_slice_buffer_add(dst, slice); |
| n -= slice_len; |
| } else if (n == slice_len) { |
| grpc_slice_buffer_add(dst, slice); |
| break; |
| } else if (incref) { /* n < slice_len */ |
| grpc_slice_buffer_undo_take_first( |
| src, grpc_slice_split_tail_maybe_ref(&slice, n, GRPC_SLICE_REF_BOTH)); |
| GPR_ASSERT(GRPC_SLICE_LENGTH(slice) == n); |
| grpc_slice_buffer_add(dst, slice); |
| break; |
| } else { /* n < slice_len */ |
| grpc_slice_buffer_undo_take_first( |
| src, grpc_slice_split_tail_maybe_ref(&slice, n, GRPC_SLICE_REF_TAIL)); |
| GPR_ASSERT(GRPC_SLICE_LENGTH(slice) == n); |
| grpc_slice_buffer_add_indexed(dst, slice); |
| break; |
| } |
| } |
| GPR_ASSERT(dst->length == output_len); |
| GPR_ASSERT(src->length == new_input_len); |
| GPR_ASSERT(src->count > 0); |
| } |
| |
| void grpc_slice_buffer_move_first(grpc_slice_buffer* src, size_t n, |
| grpc_slice_buffer* dst) { |
| slice_buffer_move_first_maybe_ref(src, n, dst, true); |
| } |
| |
| void grpc_slice_buffer_move_first_no_ref(grpc_slice_buffer* src, size_t n, |
| grpc_slice_buffer* dst) { |
| slice_buffer_move_first_maybe_ref(src, n, dst, false); |
| } |
| |
| void grpc_slice_buffer_move_first_into_buffer(grpc_slice_buffer* src, size_t n, |
| void* dst) { |
| char* dstp = static_cast<char*>(dst); |
| GPR_ASSERT(src->length >= n); |
| |
| while (n > 0) { |
| grpc_slice slice = grpc_slice_buffer_take_first(src); |
| size_t slice_len = GRPC_SLICE_LENGTH(slice); |
| if (slice_len > n) { |
| memcpy(dstp, GRPC_SLICE_START_PTR(slice), n); |
| grpc_slice_buffer_undo_take_first( |
| src, grpc_slice_sub_no_ref(slice, n, slice_len)); |
| n = 0; |
| } else if (slice_len == n) { |
| memcpy(dstp, GRPC_SLICE_START_PTR(slice), n); |
| grpc_slice_unref_internal(slice); |
| n = 0; |
| } else { |
| memcpy(dstp, GRPC_SLICE_START_PTR(slice), slice_len); |
| dstp += slice_len; |
| n -= slice_len; |
| grpc_slice_unref_internal(slice); |
| } |
| } |
| } |
| |
| void grpc_slice_buffer_trim_end(grpc_slice_buffer* sb, size_t n, |
| grpc_slice_buffer* garbage) { |
| GPR_ASSERT(n <= sb->length); |
| sb->length -= n; |
| for (;;) { |
| size_t idx = sb->count - 1; |
| grpc_slice slice = sb->slices[idx]; |
| size_t slice_len = GRPC_SLICE_LENGTH(slice); |
| if (slice_len > n) { |
| sb->slices[idx] = grpc_slice_split_head(&slice, slice_len - n); |
| if (garbage) { |
| grpc_slice_buffer_add_indexed(garbage, slice); |
| } else { |
| grpc_slice_unref_internal(slice); |
| } |
| return; |
| } else if (slice_len == n) { |
| if (garbage) { |
| grpc_slice_buffer_add_indexed(garbage, slice); |
| } else { |
| grpc_slice_unref_internal(slice); |
| } |
| sb->count = idx; |
| return; |
| } else { |
| if (garbage) { |
| grpc_slice_buffer_add_indexed(garbage, slice); |
| } else { |
| grpc_slice_unref_internal(slice); |
| } |
| n -= slice_len; |
| sb->count = idx; |
| } |
| } |
| } |
| |
| grpc_slice grpc_slice_buffer_take_first(grpc_slice_buffer* sb) { |
| grpc_slice slice; |
| GPR_ASSERT(sb->count > 0); |
| slice = sb->slices[0]; |
| sb->slices++; |
| sb->count--; |
| sb->length -= GRPC_SLICE_LENGTH(slice); |
| |
| return slice; |
| } |
| |
| void grpc_slice_buffer_undo_take_first(grpc_slice_buffer* sb, |
| grpc_slice slice) { |
| sb->slices--; |
| sb->slices[0] = slice; |
| sb->count++; |
| sb->length += GRPC_SLICE_LENGTH(slice); |
| } |