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(calc): Update bytecode for calc() to be in an lwc_string
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In order to permit us to share calc expressions between styles
and computed styles, without copying, we embed the calc expression
bytecode into an lwc string.  This is effectively using lwc_string
as an interned byte buffer, there may be a nicer way to do this in
the future.

Signed-off-by: Daniel Silverstone <[email protected]>
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@kinnison @tlsa
kinnison authored and tlsa committed Nov 27, 2022
1 parent 9434b1d commit 67364ac
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Showing 2 changed files with 84 additions and 34 deletions.
89 changes: 66 additions & 23 deletions src/parse/properties/utils.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1362,16 +1362,17 @@ css_error css__comma_list_to_style(css_language *c,
static css_error
css__parse_calc_sum(css_language *c,
const parserutils_vector *vector, int *ctx,
css_style *result);
parserutils_buffer *result);

static css_error
css__parse_calc_number(
const parserutils_vector *vector, int *ctx,
css_style *result)
parserutils_buffer *result)
{
const css_token *token;
css_fixed num;
size_t consumed;
css_code_t push = CALC_PUSH_NUMBER;

/* Consume the number token */
token = parserutils_vector_iterate(vector, ctx);
Expand All @@ -1386,13 +1387,18 @@ css__parse_calc_number(
return CSS_INVALID;
}

return css__stylesheet_style_vappend(result, 2, (css_code_t) CALC_PUSH_NUMBER, (css_code_t)num);
return css_error_from_parserutils_error(
parserutils_buffer_appendv(result, 2,
&push, sizeof(push),
&num, sizeof(num)
)
);
}

static css_error
css__parse_calc_value(css_language *c,
const parserutils_vector *vector, int *ctx,
css_style *result)
parserutils_buffer *result)
{
css_error error;
int orig_ctx = *ctx;
Expand Down Expand Up @@ -1426,6 +1432,7 @@ css__parse_calc_value(css_language *c,
{
css_fixed length = 0;
uint32_t unit = 0;
css_code_t push = CALC_PUSH_VALUE;
*ctx = orig_ctx;

error = css__parse_unit_specifier(c, vector, ctx, UNIT_CALC_NUMBER, &length, &unit);
Expand All @@ -1434,7 +1441,14 @@ css__parse_calc_value(css_language *c,
return error;
}

error = css__stylesheet_style_vappend(result, 3, (css_code_t) CALC_PUSH_VALUE, length, unit);
error = css_error_from_parserutils_error(
parserutils_buffer_appendv(result, 3,
&push, sizeof(push),
&length, sizeof(length),
&unit, sizeof(unit)
)
);

}
break;

Expand All @@ -1455,12 +1469,11 @@ css__parse_calc_value(css_language *c,
static css_error
css__parse_calc_product(css_language *c,
const parserutils_vector *vector, int *ctx,
css_style *result)
parserutils_buffer *result)
{
css_error error = CSS_OK;
const css_token *token;
bool multiplication;

css_code_t operator;

/* First parse a value */
error = css__parse_calc_value(c, vector, ctx, result);
Expand All @@ -1480,9 +1493,9 @@ css__parse_calc_product(css_language *c,
tokenIsChar(token, '-'))
break;
else if (tokenIsChar(token, '*'))
multiplication = true;
operator = CALC_MULTIPLY;
else if (tokenIsChar(token, '/'))
multiplication = false;
operator = CALC_DIVIDE;
else {
error = CSS_INVALID;
break;
Expand All @@ -1492,7 +1505,7 @@ css__parse_calc_product(css_language *c,

consumeWhitespace(vector, ctx);

if (multiplication) {
if (operator == CALC_MULTIPLY) {
/* parse another value */
error = css__parse_calc_value(c, vector, ctx, result);
} else {
Expand All @@ -1502,8 +1515,9 @@ css__parse_calc_product(css_language *c,
break;

/* emit the multiplication/division operator */
error = css__stylesheet_style_append(result,
(css_code_t) (multiplication ? CALC_MULTIPLY : CALC_DIVIDE));
error = css_error_from_parserutils_error(
parserutils_buffer_append(result, (const uint8_t *)&operator, sizeof(operator))
);
} while (1);
/* We've fallen off, either we had an error or we're left with ')' */
return error;
Expand All @@ -1513,12 +1527,11 @@ css__parse_calc_product(css_language *c,
css_error
css__parse_calc_sum(css_language *c,
const parserutils_vector *vector, int *ctx,
css_style *result)
parserutils_buffer *result)
{
css_error error = CSS_OK;
const css_token *token;
bool addition;

css_code_t operator;

/* First parse a product */
error = css__parse_calc_product(c, vector, ctx, result);
Expand All @@ -1535,9 +1548,9 @@ css__parse_calc_sum(css_language *c,
} else if (tokenIsChar(token, ')'))
break;
else if (tokenIsChar(token, '+'))
addition = true;
operator = CALC_ADD;
else if (tokenIsChar(token, '-'))
addition = false;
operator = CALC_SUBTRACT;
else {
error = CSS_INVALID;
break;
Expand All @@ -1552,7 +1565,9 @@ css__parse_calc_sum(css_language *c,
break;

/* emit the addition/subtraction operator */
error = css__stylesheet_style_append(result, (css_code_t) (addition ? CALC_ADD : CALC_SUBTRACT));
error = css_error_from_parserutils_error(
parserutils_buffer_append(result, (const uint8_t *)&operator, sizeof(operator))
);
} while (1);
/* We've fallen off, either we had an error or we're left with ')' */
return error;
Expand All @@ -1569,6 +1584,10 @@ css_error css__parse_calc(css_language *c,
const css_token *token;
css_error error = CSS_OK;
css_style *calc_style = NULL;
parserutils_buffer *calc_buffer = NULL;
lwc_string *calc_expr = NULL;
uint32_t expr_index = 0;
css_code_t finish = CALC_FINISH;

consumeWhitespace(vector, ctx);

Expand All @@ -1578,19 +1597,25 @@ css_error css__parse_calc(css_language *c,
return CSS_INVALID;
}

if (parserutils_buffer_create(&calc_buffer) != PARSERUTILS_OK) {
/* Since &calc_buffer is valid, the only error case is NONMEM */
*ctx = orig_ctx;
return CSS_NOMEM;
}

error = css__stylesheet_style_create(c->sheet, &calc_style);
if (error != CSS_OK)
goto cleanup;

error = css__stylesheet_style_append(calc_style, property);
if (error != CSS_OK)
goto cleanup;

error = css__stylesheet_style_append(calc_style, (css_code_t) unit);
if (error != CSS_OK)
goto cleanup;

error = css__parse_calc_sum(c, vector, ctx, calc_style);
error = css__parse_calc_sum(c, vector, ctx, calc_buffer);
if (error != CSS_OK)
goto cleanup;

Expand All @@ -1602,17 +1627,35 @@ css_error css__parse_calc(css_language *c,
goto cleanup;
}

/* Append the indicator that the calc is finished */
error = css_error_from_parserutils_error(
parserutils_buffer_append(calc_buffer, (const uint8_t *)&finish, sizeof(finish))
);
if (error != CSS_OK)
goto cleanup;

/* Swallow that close paren */
parserutils_vector_iterate(vector, ctx);

/* Append the indicator that the calc is finished */
error = css__stylesheet_style_append(calc_style, (css_code_t) CALC_FINISH);
/* Create the lwc string representing the calculation and store it in */
error = css_error_from_lwc_error(
lwc_intern_string((const char *)calc_buffer->data, calc_buffer->length, &calc_expr)
);
if (error != CSS_OK)
goto cleanup;

/* This always takes ownership of calc_expr, so we should not use after this */
error = css__stylesheet_string_add(calc_style->sheet, calc_expr, &expr_index);
if (error != CSS_OK)
goto cleanup;

css__stylesheet_style_append(calc_style, (css_code_t) expr_index);

error = css__stylesheet_merge_style(result, calc_style);
cleanup:
css__stylesheet_style_destroy(calc_style);
parserutils_buffer_destroy(calc_buffer);
/* We do not need to clean up calc_expr, it will never leak */
if (error != CSS_OK) {
*ctx = orig_ctx;
}
Expand Down
29 changes: 18 additions & 11 deletions test/dump.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -803,15 +803,23 @@ void dump_bytecode(css_style *style, char **ptr, uint32_t depth)
} else if (getFlagValue(opv) == FLAG_VALUE_UNSET) {
*ptr += sprintf(*ptr, "unset");
} else if (isCalc(opv)) {
lwc_string *calc_expr = NULL;
const uint8_t *codeptr = NULL;
css_code_t calc_opcode;
uint32_t unit, snum;
/* First entry is a unit */
uint32_t unit = *((uint32_t *)bytecode);
unit = *((uint32_t *)bytecode);
ADVANCE(sizeof(unit));
/* Second entry is an lwc_string of the expression */
snum = *((uint32_t *)bytecode);
ADVANCE(sizeof(snum));
css__stylesheet_string_get(style->sheet, snum, &calc_expr);
codeptr = (const uint8_t *)lwc_string_data(calc_expr);
*ptr += sprintf(*ptr, "/* -> ");
dump_unit(0, unit, ptr);
*ptr += sprintf(*ptr, " */ calc(");
css_code_t calc_opcode;
while ((calc_opcode = *((css_code_t *)bytecode)) != CALC_FINISH) {
ADVANCE(sizeof(calc_opcode));
while ((calc_opcode = *((css_code_t *)codeptr)) != CALC_FINISH) {
codeptr += sizeof(calc_opcode);
switch (calc_opcode) {
case CALC_ADD:
*ptr += sprintf(*ptr, "+ ");
Expand All @@ -826,17 +834,17 @@ void dump_bytecode(css_style *style, char **ptr, uint32_t depth)
*ptr += sprintf(*ptr, "/ ");
break;
case CALC_PUSH_VALUE: {
css_fixed num = *((css_fixed *)bytecode);
ADVANCE(sizeof(num));
uint32_t unit = *((uint32_t *)bytecode);
ADVANCE(sizeof(unit));
css_fixed num = *((css_fixed *)codeptr);
codeptr += sizeof(num);
uint32_t unit = *((uint32_t *)codeptr);
codeptr += sizeof(unit);
dump_unit(num, unit, ptr);
*ptr += sprintf(*ptr, " ");
break;
}
case CALC_PUSH_NUMBER: {
css_fixed num = *((css_fixed *)bytecode);
ADVANCE(sizeof(num));
css_fixed num = *((css_fixed *)codeptr);
codeptr += sizeof(num);
dump_number(num, ptr);
*ptr += sprintf(*ptr, " ");
break;
Expand All @@ -846,7 +854,6 @@ void dump_bytecode(css_style *style, char **ptr, uint32_t depth)
break;
}
}
ADVANCE(sizeof(calc_opcode));
*ptr += sprintf(*ptr, "=)");
} else {
value = getValue(opv);
Expand Down

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