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zstd-compressed state images

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This commit is contained in:
Fabian 2020-12-31 19:14:34 -06:00
parent 10b8da4230
commit 0fee2a567a
1 changed files with 116 additions and 54 deletions
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170
src/state.js
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@ -21,6 +21,7 @@ var STATE_INDEX_INFO_LEN = 3;
/** @const */
var STATE_INFO_BLOCK_START = 16;
const ZSTD_MAGIC = 0xFD2FB528;
/** @constructor */
function StateLoadError(msg)
@ -118,19 +119,8 @@ function restore_buffers(obj, buffers)
const constructor = CONSTRUCTOR_TABLE[type];
dbg_assert(constructor, "Unkown type: " + type);
const info = buffers.infos[obj["buffer_id"]];
// restore large buffers by just returning a view on the state blob
// get_state is responsible for copying the data
if(info.length >= 1024 * 1024 && constructor === Uint8Array)
{
return new Uint8Array(buffers.full, info.offset, info.length);
}
else
{
var buf = buffers.full.slice(info.offset, info.offset + info.length);
return new constructor(buf);
}
const buffer = buffers[obj["buffer_id"]];
return new constructor(buffer);
}
CPU.prototype.save_state = function()
@ -194,44 +184,47 @@ CPU.prototype.save_state = function()
buffer_block.set(buffer, buffer_infos[i].offset);
}
dbg_log("State: json size " + (info_block.byteLength >> 10) + "k");
dbg_log("State: Total buffers size " + (buffer_block.byteLength >> 10) + "k");
return result;
};
CPU.prototype.restore_state = function(state)
{
var len = state.byteLength;
state = new Uint8Array(state);
if(len < STATE_INFO_BLOCK_START)
function read_state_header(state, check_length)
{
throw new StateLoadError("Invalid length: " + len);
}
const len = state.length;
var header_block = new Int32Array(state, 0, 4);
if(len < STATE_INFO_BLOCK_START)
{
throw new StateLoadError("Invalid length: " + len);
}
if(header_block[STATE_INDEX_MAGIC] !== STATE_MAGIC)
{
throw new StateLoadError("Invalid header: " + h(header_block[STATE_INDEX_MAGIC] >>> 0));
}
const header_block = new Int32Array(state.buffer, state.byteOffset, 4);
if(header_block[STATE_INDEX_VERSION] !== STATE_VERSION)
{
throw new StateLoadError(
"Version mismatch: dump=" + header_block[STATE_INDEX_VERSION] +
" we=" + STATE_VERSION);
}
if(header_block[STATE_INDEX_MAGIC] !== STATE_MAGIC)
{
throw new StateLoadError("Invalid header: " + h(header_block[STATE_INDEX_MAGIC] >>> 0));
}
if(header_block[STATE_INDEX_TOTAL_LEN] !== len)
{
throw new StateLoadError(
"Length doesn't match header: " +
"real=" + len + " header=" + header_block[STATE_INDEX_TOTAL_LEN]);
}
if(header_block[STATE_INDEX_VERSION] !== STATE_VERSION)
{
throw new StateLoadError(
"Version mismatch: dump=" + header_block[STATE_INDEX_VERSION] +
" we=" + STATE_VERSION);
}
var info_block_len = header_block[STATE_INDEX_INFO_LEN];
if(check_length && header_block[STATE_INDEX_TOTAL_LEN] !== len)
{
throw new StateLoadError(
"Length doesn't match header: " +
"real=" + len + " header=" + header_block[STATE_INDEX_TOTAL_LEN]);
}
if(info_block_len < 0 || info_block_len + 12 >= state.length)
{
throw new StateLoadError("Invalid info block length: " + info_block_len);
return header_block[STATE_INDEX_INFO_LEN];
}
function read_info_block(info_block_buffer)
@ -240,24 +233,93 @@ CPU.prototype.restore_state = function(state)
return JSON.parse(info_block);
}
const info_block_buffer = new Uint8Array(state, STATE_INFO_BLOCK_START, info_block_len);
var info_block_obj = read_info_block(info_block_buffer);
var state_object = info_block_obj["state"];
var buffer_infos = info_block_obj["buffer_infos"];
var buffer_block_start = STATE_INFO_BLOCK_START + info_block_len;
buffer_block_start = buffer_block_start + 3 & ~3;
for(var i = 0; i < buffer_infos.length; i++)
if(new Uint32Array(state.buffer, 0, 1)[0] === ZSTD_MAGIC)
{
buffer_infos[i].offset += buffer_block_start;
const ctx = this.zstd_create_ctx(state.length);
new Uint8Array(this.wasm_memory.buffer, this.zstd_get_src_ptr(ctx), state.length).set(state);
let ptr = this.zstd_read(ctx, 16);
const header_block = new Uint8Array(this.wasm_memory.buffer, ptr, 16);
const info_block_len = read_state_header(header_block, false);
this.zstd_read_free(ptr, 16);
ptr = this.zstd_read(ctx, info_block_len);
const info_block_buffer = new Uint8Array(this.wasm_memory.buffer, ptr, info_block_len);
const info_block_obj = read_info_block(info_block_buffer);
this.zstd_read_free(ptr, info_block_len);
let state_object = info_block_obj["state"];
const buffer_infos = info_block_obj["buffer_infos"];
const buffers = [];
let position = STATE_INFO_BLOCK_START + info_block_len;
for(const buffer_info of buffer_infos)
{
const front_padding = (position + 3 & ~3) - position;
const CHUNK_SIZE = 1 * 1024 * 1024;
if(buffer_info.length > CHUNK_SIZE)
{
const ptr = this.zstd_read(ctx, front_padding);
this.zstd_read_free(ptr, front_padding);
const buffer = new Uint8Array(buffer_info.length);
buffers.push(buffer.buffer);
let have = 0;
while(have < buffer_info.length)
{
const remaining = buffer_info.length - have;
dbg_assert(remaining >= 0);
const to_read = Math.min(remaining, CHUNK_SIZE);
const ptr = this.zstd_read(ctx, to_read);
buffer.set(new Uint8Array(this.wasm_memory.buffer, ptr, to_read), have);
this.zstd_read_free(ptr, to_read);
have += to_read;
}
}
else
{
const ptr = this.zstd_read(ctx, front_padding + buffer_info.length);
const offset = ptr + front_padding;
buffers.push(this.wasm_memory.buffer.slice(offset, offset + buffer_info.length));
this.zstd_read_free(ptr, front_padding + buffer_info.length);
}
position += front_padding + buffer_info.length;
}
state_object = restore_buffers(state_object, buffers);
this.set_state(state_object);
this.zstd_free_ctx(ctx);
}
else
{
const info_block_len = read_state_header(state, true);
var buffers = {
full: state,
infos: buffer_infos,
};
if(info_block_len < 0 || info_block_len + 12 >= state.length)
{
throw new StateLoadError("Invalid info block length: " + info_block_len);
}
state_object = restore_buffers(state_object, buffers);
this.set_state(state_object);
const info_block_buffer = state.subarray(STATE_INFO_BLOCK_START, STATE_INFO_BLOCK_START + info_block_len);
const info_block_obj = read_info_block(info_block_buffer);
let state_object = info_block_obj["state"];
const buffer_infos = info_block_obj["buffer_infos"];
let buffer_block_start = STATE_INFO_BLOCK_START + info_block_len;
buffer_block_start = buffer_block_start + 3 & ~3;
const buffers = buffer_infos.map(buffer_info => {
const offset = buffer_block_start + buffer_info.offset;
return state.buffer.slice(offset, offset + buffer_info.length);
});
state_object = restore_buffers(state_object, buffers);
this.set_state(state_object);
}
};