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Shell: Make 'for' loops read their input as an stream

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i.e. process an element as it becomes available.
This commit is contained in:
AnotherTest 2020-08-21 03:48:23 +04:30 • committed by Andreas Kling
parent 9cc996b1e5
commit d4bcc689fb
2 changed files with 101 additions and 15 deletions
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114
Shell/AST.cpp
View file

@ -80,6 +80,20 @@ static inline Vector<Command> join_commands(Vector<Command> left, Vector<Command
return commands;
}
void Node::for_each_entry(RefPtr<Shell> shell, Function<IterationDecision(RefPtr<Value>)> callback)
{
auto value = run(shell)->resolve_without_cast(shell);
if (value->is_job()) {
callback(value);
return;
}
auto list = value->resolve_as_list(shell);
for (auto& element : list) {
if (callback(create<StringValue>(move(element))) == IterationDecision::Break)
break;
}
}
void Node::dump(int level) const
{
print_indented(String::format("%s at %d:%d", class_name().characters(), m_position.start_offset, m_position.end_offset), level);
@ -871,12 +885,10 @@ void Execute::dump(int level) const
m_command->dump(level + 1);
}
RefPtr<Value> Execute::run(RefPtr<Shell> shell)
void Execute::for_each_entry(RefPtr<Shell> shell, Function<IterationDecision(RefPtr<Value>)> callback)
{
RefPtr<Job> job;
if (m_command->would_execute())
return m_command->run(shell);
return m_command->for_each_entry(shell, move(callback));
auto commands = shell->expand_aliases(m_command->run(shell)->resolve_as_commands(shell));
@ -885,7 +897,7 @@ RefPtr<Value> Execute::run(RefPtr<Shell> shell)
int rc = pipe(pipefd);
if (rc < 0) {
dbg() << "Error: cannot pipe(): " << strerror(errno);
return create<StringValue>("");
return;
}
auto& last_in_commands = commands.last();
@ -895,14 +907,55 @@ RefPtr<Value> Execute::run(RefPtr<Shell> shell)
last_in_commands.is_pipe_source = false;
auto notifier = Core::Notifier::construct(pipefd[0], Core::Notifier::Read);
StringBuilder builder;
DuplexMemoryStream stream;
enum {
Continue,
Break,
NothingLeft,
};
auto check_and_call = [&] {
auto ifs = shell->local_variable_or("IFS", "\n");
if (auto offset = stream.offset_of(ifs.bytes()); offset.has_value()) {
auto line_end = offset.value();
if (line_end == 0) {
auto rc = stream.discard_or_error(ifs.length());
ASSERT(rc);
if (shell->options.inline_exec_keep_empty_segments)
if (callback(create<StringValue>("")) == IterationDecision::Break) {
notifier->set_enabled(false);
// FIXME: Kill all the jobs here.
return Break;
}
} else {
auto entry = ByteBuffer::create_uninitialized(line_end + ifs.length());
auto rc = stream.read_or_error(entry);
ASSERT(rc);
auto str = StringView(entry.data(), entry.size() - ifs.length());
if (callback(create<StringValue>(str)) == IterationDecision::Break) {
notifier->set_enabled(false);
// FIXME: Kill all the jobs here.
return Break;
}
}
return Continue;
}
return NothingLeft;
};
auto try_read = [&] {
u8 buffer[4096];
size_t remaining_size = 4096;
constexpr static auto buffer_size = 4096;
u8 buffer[buffer_size];
size_t remaining_size = buffer_size;
for (;;) {
if (remaining_size == 0)
break;
if (check_and_call() == Break)
return;
auto read_size = read(pipefd[0], buffer, remaining_size);
if (read_size < 0) {
if (errno == EINTR)
@ -914,10 +967,9 @@ RefPtr<Value> Execute::run(RefPtr<Shell> shell)
}
if (read_size == 0)
break;
remaining_size -= read_size;
}
builder.append(StringView { buffer, 4096 - remaining_size });
stream.write({ buffer, (size_t)read_size });
}
};
notifier->on_ready_to_read = [&] {
@ -936,7 +988,23 @@ RefPtr<Value> Execute::run(RefPtr<Shell> shell)
dbg() << "close() failed: " << strerror(errno);
}
return create<StringValue>(builder.build(), shell->local_variable_or("IFS", "\n"), shell->options.inline_exec_keep_empty_segments);
if (!stream.eof()) {
auto action = Continue;
do {
action = check_and_call();
if (action == Break)
return;
} while (action == Continue);
if (!stream.eof()) {
auto entry = ByteBuffer::create_uninitialized(stream.remaining());
auto rc = stream.read_or_error(entry);
ASSERT(rc);
callback(create<StringValue>(String::copy(entry)));
}
}
return;
}
RefPtr<Job> last_job;
@ -946,7 +1014,23 @@ RefPtr<Value> Execute::run(RefPtr<Shell> shell)
last_job = move(job);
}
return create<JobValue>(move(last_job));
callback(create<JobValue>(move(last_job)));
return;
}
RefPtr<Value> Execute::run(RefPtr<Shell> shell)
{
NonnullRefPtrVector<Value> values;
for_each_entry(shell, [&](auto value) {
values.append(*value);
return IterationDecision::Continue;
});
if (values.size() == 1 && values.first().is_job())
return values.first();
return create<ListValue>(move(values));
}
void Execute::highlight_in_editor(Line::Editor& editor, Shell& shell, HighlightMetadata metadata)

2
Shell/AST.h
View file

@ -352,6 +352,7 @@ private:
class Node : public RefCounted<Node> {
public:
virtual void dump(int level) const = 0;
virtual void for_each_entry(RefPtr<Shell> shell, Function<IterationDecision(RefPtr<Value>)> callback);
virtual RefPtr<Value> run(RefPtr<Shell>) = 0;
virtual void highlight_in_editor(Line::Editor&, Shell&, HighlightMetadata = {}) = 0;
virtual Vector<Line::CompletionSuggestion> complete_for_editor(Shell&, size_t, const HitTestResult&);
@ -657,6 +658,7 @@ public:
virtual ~Execute();
void capture_stdout() { m_capture_stdout = true; }
RefPtr<Node> command() { return m_command; }
virtual void for_each_entry(RefPtr<Shell> shell, Function<IterationDecision(RefPtr<Value>)> callback) override;
private:
virtual void dump(int level) const override;