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LibJS: Use fallible methods to handle OOM when resolving rope strings

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Timothy Flynn 2023-01-07 15:33:15 -05:00 • committed by Linus Groh
parent 115baa7e32
commit 6e1a239a62
1 changed files with 16 additions and 15 deletions
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31
Userland/Libraries/LibJS/Runtime/PrimitiveString.cpp
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@ -12,6 +12,7 @@
#include <LibJS/Runtime/GlobalObject.h>
#include <LibJS/Runtime/PrimitiveString.h>
#include <LibJS/Runtime/PropertyKey.h>
#include <LibJS/Runtime/ThrowableStringBuilder.h>
#include <LibJS/Runtime/VM.h>
#include <LibJS/Runtime/Value.h>
@ -181,7 +182,7 @@ ThrowCompletionOr<void> PrimitiveString::resolve_rope_if_needed() const
auto const& rhs_string = TRY(m_rhs->utf16_string());
Utf16Data combined;
combined.ensure_capacity(lhs_string.length_in_code_units() + rhs_string.length_in_code_units());
TRY_OR_THROW_OOM(vm, combined.try_ensure_capacity(lhs_string.length_in_code_units() + rhs_string.length_in_code_units()));
combined.extend(lhs_string.string());
combined.extend(rhs_string.string());
@ -199,27 +200,27 @@ ThrowCompletionOr<void> PrimitiveString::resolve_rope_if_needed() const
// NOTE: We traverse the rope tree without using recursion, since we'd run out of
// stack space quickly when handling a long sequence of unresolved concatenations.
Vector<PrimitiveString const*> stack;
stack.append(m_rhs);
stack.append(m_lhs);
TRY_OR_THROW_OOM(vm, stack.try_append(m_rhs));
TRY_OR_THROW_OOM(vm, stack.try_append(m_lhs));
while (!stack.is_empty()) {
auto* current = stack.take_last();
auto const* current = stack.take_last();
if (current->m_is_rope) {
stack.append(current->m_rhs);
stack.append(current->m_lhs);
TRY_OR_THROW_OOM(vm, stack.try_append(current->m_rhs));
TRY_OR_THROW_OOM(vm, stack.try_append(current->m_lhs));
continue;
}
pieces.append(current);
TRY_OR_THROW_OOM(vm, pieces.try_append(current));
}
// Now that we have all the pieces, we can concatenate them using a StringBuilder.
StringBuilder builder;
ThrowableStringBuilder builder(vm);
// We keep track of the previous piece in order to handle surrogate pairs spread across two pieces.
PrimitiveString const* previous = nullptr;
for (auto const* current : pieces) {
if (!previous) {
// This is the very first piece, just append it and continue.
builder.append(TRY(current->deprecated_string()));
TRY(builder.append(TRY(current->deprecated_string())));
previous = current;
continue;
}
@ -233,7 +234,7 @@ ThrowCompletionOr<void> PrimitiveString::resolve_rope_if_needed() const
// Surrogates encoded as UTF-8 are 3 bytes.
if ((previous_string_as_utf8.length() < 3) || (current_string_as_utf8.length() < 3)) {
builder.append(TRY(current->deprecated_string()));
TRY(builder.append(TRY(current->deprecated_string())));
previous = current;
continue;
}
@ -241,7 +242,7 @@ ThrowCompletionOr<void> PrimitiveString::resolve_rope_if_needed() const
// Might the previous string end with a UTF-8 encoded surrogate?
if ((static_cast<u8>(previous_string_as_utf8[previous_string_as_utf8.length() - 3]) & 0xf0) != 0xe0) {
// If not, just append the current string and continue.
builder.append(TRY(current->deprecated_string()));
TRY(builder.append(TRY(current->deprecated_string())));
previous = current;
continue;
}
@ -249,7 +250,7 @@ ThrowCompletionOr<void> PrimitiveString::resolve_rope_if_needed() const
// Might the current string begin with a UTF-8 encoded surrogate?
if ((static_cast<u8>(current_string_as_utf8[0]) & 0xf0) != 0xe0) {
// If not, just append the current string and continue.
builder.append(TRY(current->deprecated_string()));
TRY(builder.append(TRY(current->deprecated_string())));
previous = current;
continue;
}
@ -258,17 +259,17 @@ ThrowCompletionOr<void> PrimitiveString::resolve_rope_if_needed() const
auto low_surrogate = *Utf8View(current_string_as_utf8).begin();
if (!Utf16View::is_high_surrogate(high_surrogate) || !Utf16View::is_low_surrogate(low_surrogate)) {
builder.append(TRY(current->deprecated_string()));
TRY(builder.append(TRY(current->deprecated_string())));
previous = current;
continue;
}
// Remove 3 bytes from the builder and replace them with the UTF-8 encoded code point.
builder.trim(3);
builder.append_code_point(Utf16View::decode_surrogate_pair(high_surrogate, low_surrogate));
TRY(builder.append_code_point(Utf16View::decode_surrogate_pair(high_surrogate, low_surrogate)));
// Append the remaining part of the current string.
builder.append(current_string_as_utf8.substring_view(3));
TRY(builder.append(current_string_as_utf8.substring_view(3)));
previous = current;
}