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src: use string_view for report and related code
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Use `std::string_view` for process.report code and related
code, drop a few unnecessary `std::to_string` calls,
and use `MaybeStackBuffer` instead of `MallocedBuffer`,
all in order to avoid unnecessary heap allocations.

PR-URL: #46723
Reviewed-By: Tobias Nießen <tniessen@tnie.de>
Reviewed-By: Yagiz Nizipli <yagiz@nizipli.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Darshan Sen <raisinten@gmail.com>
Reviewed-By: Chengzhong Wu <legendecas@gmail.com>
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@addaleax
addaleax committed Feb 20, 2023
1 parent ff92b40 commit b85b5ba
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Showing 7 changed files with 76 additions and 64 deletions.
4 changes: 2 additions & 2 deletions src/json_utils.cc
View file
Expand Up @@ -2,8 +2,8 @@

namespace node {

std::string EscapeJsonChars(const std::string& str) {
const std::string control_symbols[0x20] = {
std::string EscapeJsonChars(std::string_view str) {
static const std::string_view control_symbols[0x20] = {
"\\u0000", "\\u0001", "\\u0002", "\\u0003", "\\u0004", "\\u0005",
"\\u0006", "\\u0007", "\\b", "\\t", "\\n", "\\u000b",
"\\f", "\\r", "\\u000e", "\\u000f", "\\u0010", "\\u0011",
Expand Down
25 changes: 18 additions & 7 deletions src/json_utils.h
View file
Expand Up @@ -4,13 +4,21 @@
#if defined(NODE_WANT_INTERNALS) && NODE_WANT_INTERNALS

#include <iomanip>
#include <ostream>
#include <limits>
#include <ostream>
#include <string>
#include <string_view>

namespace node {

std::string EscapeJsonChars(const std::string& str);
constexpr bool NeedsJsonEscape(std::string_view str) {
for (const char c : str) {
if (c == '\\' || c == '"' || c < 0x20) return true;
}
return false;
}

std::string EscapeJsonChars(std::string_view str);
std::string Reindent(const std::string& str, int indentation);

// JSON compiler definitions.
Expand Down Expand Up @@ -135,17 +143,20 @@ class JSONWriter {
}

inline void write_value(Null null) { out_ << "null"; }
inline void write_value(const char* str) { write_string(str); }
inline void write_value(const std::string& str) { write_string(str); }
inline void write_value(std::string_view str) { write_string(str); }

inline void write_value(const ForeignJSON& json) {
out_ << Reindent(json.as_string, indent_);
}

inline void write_string(const std::string& str) {
out_ << '"' << EscapeJsonChars(str) << '"';
inline void write_string(std::string_view str) {
out_ << '"';
if (NeedsJsonEscape(str)) // only create temporary std::string if necessary
out_ << EscapeJsonChars(str);
else
out_ << str;
out_ << '"';
}
inline void write_string(const char* str) { write_string(std::string(str)); }

enum JSONState { kObjectStart, kAfterValue };
std::ostream& out_;
Expand Down
2 changes: 1 addition & 1 deletion src/node_api.cc
View file
Expand Up @@ -657,7 +657,7 @@ void napi_module_register_by_symbol(v8::Local<v8::Object> exports,
// a file system path.
// TODO(gabrielschulhof): Pass the `filename` through unchanged if/when we
// receive it as a URL already.
module_filename = node::url::FromFilePath(filename.ToString());
module_filename = node::url::FromFilePath(filename.ToStringView());
}

// Create a new napi_env for this specific module.
Expand Down
6 changes: 4 additions & 2 deletions src/node_errors.cc
View file
Expand Up @@ -420,8 +420,10 @@ static void ReportFatalException(Environment* env,
// Not an error object. Just print as-is.
node::Utf8Value message(env->isolate(), error);

FPrintF(stderr, "%s\n",
*message ? message.ToString() : "<toString() threw exception>");
FPrintF(
stderr,
"%s\n",
*message ? message.ToStringView() : "<toString() threw exception>");
} else {
node::Utf8Value name_string(env->isolate(), name.ToLocalChecked());
node::Utf8Value message_string(env->isolate(), message.ToLocalChecked());
Expand Down
28 changes: 14 additions & 14 deletions src/node_report.cc
View file
Expand Up @@ -400,11 +400,10 @@ static void PrintJavaScriptErrorProperties(JSONWriter* writer,
!value->ToString(context).ToLocal(&value_string)) {
continue;
}
String::Utf8Value k(isolate, key);
node::Utf8Value k(isolate, key);
if (!strcmp(*k, "stack") || !strcmp(*k, "message")) continue;
String::Utf8Value v(isolate, value_string);
writer->json_keyvalue(std::string(*k, k.length()),
std::string(*v, v.length()));
node::Utf8Value v(isolate, value_string);
writer->json_keyvalue(k.ToStringView(), v.ToStringView());
}
}
writer->json_objectend(); // the end of 'errorProperties'
Expand Down Expand Up @@ -631,27 +630,26 @@ static void PrintResourceUsage(JSONWriter* writer) {
uint64_t free_memory = uv_get_free_memory();
uint64_t total_memory = uv_get_total_memory();

writer->json_keyvalue("free_memory", std::to_string(free_memory));
writer->json_keyvalue("total_memory", std::to_string(total_memory));
writer->json_keyvalue("free_memory", free_memory);
writer->json_keyvalue("total_memory", total_memory);

size_t rss;
int err = uv_resident_set_memory(&rss);
if (!err) {
writer->json_keyvalue("rss", std::to_string(rss));
writer->json_keyvalue("rss", rss);
}

uint64_t constrained_memory = uv_get_constrained_memory();
if (constrained_memory) {
writer->json_keyvalue("constrained_memory",
std::to_string(constrained_memory));
writer->json_keyvalue("constrained_memory", constrained_memory);
}

// See GuessMemoryAvailableToTheProcess
if (!err && constrained_memory && constrained_memory >= rss) {
uint64_t available_memory = constrained_memory - rss;
writer->json_keyvalue("available_memory", std::to_string(available_memory));
writer->json_keyvalue("available_memory", available_memory);
} else {
writer->json_keyvalue("available_memory", std::to_string(free_memory));
writer->json_keyvalue("available_memory", free_memory);
}

if (uv_getrusage(&rusage) == 0) {
Expand All @@ -668,7 +666,7 @@ static void PrintResourceUsage(JSONWriter* writer) {
writer->json_keyvalue("cpuConsumptionPercent", cpu_percentage);
writer->json_keyvalue("userCpuConsumptionPercent", user_cpu_percentage);
writer->json_keyvalue("kernelCpuConsumptionPercent", kernel_cpu_percentage);
writer->json_keyvalue("maxRss", std::to_string(rusage.ru_maxrss * 1024));
writer->json_keyvalue("maxRss", rusage.ru_maxrss * 1024);
writer->json_objectstart("pageFaults");
writer->json_keyvalue("IORequired", rusage.ru_majflt);
writer->json_keyvalue("IONotRequired", rusage.ru_minflt);
Expand Down Expand Up @@ -795,13 +793,15 @@ static void PrintComponentVersions(JSONWriter* writer) {
writer->json_objectstart("componentVersions");

#define V(key) +1
std::pair<std::string, std::string> versions_array[NODE_VERSIONS_KEYS(V)];
std::pair<std::string_view, std::string_view>
versions_array[NODE_VERSIONS_KEYS(V)];
#undef V
auto* slot = &versions_array[0];

#define V(key) \
do { \
*slot++ = std::make_pair(#key, per_process::metadata.versions.key); \
*slot++ = std::pair<std::string_view, std::string_view>( \
#key, per_process::metadata.versions.key); \
} while (0);
NODE_VERSIONS_KEYS(V)
#undef V
Expand Down
62 changes: 29 additions & 33 deletions src/node_report_utils.cc
View file
Expand Up @@ -83,79 +83,75 @@ static void ReportEndpoints(uv_handle_t* h, JSONWriter* writer) {
// Utility function to format libuv pipe information.
static void ReportPipeEndpoints(uv_handle_t* h, JSONWriter* writer) {
uv_any_handle* handle = reinterpret_cast<uv_any_handle*>(h);
MallocedBuffer<char> buffer(0);
size_t buffer_size = 0;
MaybeStackBuffer<char> buffer;
size_t buffer_size = buffer.capacity();
int rc = -1;

// First call to get required buffer size.
rc = uv_pipe_getsockname(&handle->pipe, buffer.data, &buffer_size);
rc = uv_pipe_getsockname(&handle->pipe, buffer.out(), &buffer_size);
if (rc == UV_ENOBUFS) {
buffer = MallocedBuffer<char>(buffer_size);
if (buffer.data != nullptr) {
rc = uv_pipe_getsockname(&handle->pipe, buffer.data, &buffer_size);
} else {
buffer_size = 0;
}
buffer.AllocateSufficientStorage(buffer_size);
rc = uv_pipe_getsockname(&handle->pipe, buffer.out(), &buffer_size);
}
if (rc == 0 && buffer_size != 0 && buffer.data != nullptr) {
writer->json_keyvalue("localEndpoint", buffer.data);
if (rc == 0 && buffer_size != 0) {
buffer.SetLength(buffer_size);
writer->json_keyvalue("localEndpoint", buffer.ToStringView());
} else {
writer->json_keyvalue("localEndpoint", null);
}

// First call to get required buffer size.
rc = uv_pipe_getpeername(&handle->pipe, buffer.data, &buffer_size);
buffer_size = buffer.capacity();
rc = uv_pipe_getpeername(&handle->pipe, buffer.out(), &buffer_size);
if (rc == UV_ENOBUFS) {
buffer = MallocedBuffer<char>(buffer_size);
if (buffer.data != nullptr) {
rc = uv_pipe_getpeername(&handle->pipe, buffer.data, &buffer_size);
}
buffer.AllocateSufficientStorage(buffer_size);
rc = uv_pipe_getpeername(&handle->pipe, buffer.out(), &buffer_size);
}
if (rc == 0 && buffer_size != 0 && buffer.data != nullptr) {
writer->json_keyvalue("remoteEndpoint", buffer.data);
if (rc == 0 && buffer_size != 0) {
buffer.SetLength(buffer_size);
writer->json_keyvalue("remoteEndpoint", buffer.ToStringView());
} else {
writer->json_keyvalue("remoteEndpoint", null);
}
}

// Utility function to format libuv path information.
static void ReportPath(uv_handle_t* h, JSONWriter* writer) {
MallocedBuffer<char> buffer(0);
MaybeStackBuffer<char> buffer;
int rc = -1;
size_t size = 0;
size_t size = buffer.capacity();
uv_any_handle* handle = reinterpret_cast<uv_any_handle*>(h);
bool wrote_filename = false;
// First call to get required buffer size.
switch (h->type) {
case UV_FS_EVENT:
rc = uv_fs_event_getpath(&(handle->fs_event), buffer.data, &size);
rc = uv_fs_event_getpath(&(handle->fs_event), buffer.out(), &size);
break;
case UV_FS_POLL:
rc = uv_fs_poll_getpath(&(handle->fs_poll), buffer.data, &size);
rc = uv_fs_poll_getpath(&(handle->fs_poll), buffer.out(), &size);
break;
default:
break;
}
if (rc == UV_ENOBUFS) {
buffer = MallocedBuffer<char>(size + 1);
buffer.AllocateSufficientStorage(size);
switch (h->type) {
case UV_FS_EVENT:
rc = uv_fs_event_getpath(&(handle->fs_event), buffer.data, &size);
rc = uv_fs_event_getpath(&(handle->fs_event), buffer.out(), &size);
break;
case UV_FS_POLL:
rc = uv_fs_poll_getpath(&(handle->fs_poll), buffer.data, &size);
rc = uv_fs_poll_getpath(&(handle->fs_poll), buffer.out(), &size);
break;
default:
break;
}
if (rc == 0) {
// buffer is not null terminated.
buffer.data[size] = '\0';
writer->json_keyvalue("filename", buffer.data);
wrote_filename = true;
}
}
if (!wrote_filename) writer->json_keyvalue("filename", null);

if (rc == 0 && size > 0) {
buffer.SetLength(size);
writer->json_keyvalue("filename", buffer.ToStringView());
} else {
writer->json_keyvalue("filename", null);
}
}

// Utility function to walk libuv handles.
Expand Down
13 changes: 8 additions & 5 deletions src/util.h
View file
Expand Up @@ -38,10 +38,10 @@
#include <array>
#include <limits>
#include <memory>
#include <set>
#include <string>
#include <string_view>
#include <type_traits>
#include <set>
#include <unordered_map>
#include <utility>
#include <vector>
Expand Down Expand Up @@ -486,6 +486,11 @@ class MaybeStackBuffer {
free(buf_);
}

inline std::basic_string<T> ToString() const { return {out(), length()}; }
inline std::basic_string_view<T> ToStringView() const {
return {out(), length()};
}

private:
size_t length_;
// capacity of the malloc'ed buf_
Expand Down Expand Up @@ -533,8 +538,6 @@ class Utf8Value : public MaybeStackBuffer<char> {
public:
explicit Utf8Value(v8::Isolate* isolate, v8::Local<v8::Value> value);

inline std::string ToString() const { return std::string(out(), length()); }

inline bool operator==(const char* a) const {
return strcmp(out(), a) == 0;
}
Expand Down Expand Up @@ -609,7 +612,7 @@ struct MallocedBuffer {
}

void Truncate(size_t new_size) {
CHECK(new_size <= size);
CHECK_LE(new_size, size);
size = new_size;
}

Expand All @@ -618,7 +621,7 @@ struct MallocedBuffer {
data = UncheckedRealloc(data, new_size);
}

inline bool is_empty() const { return data == nullptr; }
bool is_empty() const { return data == nullptr; }

MallocedBuffer() : data(nullptr), size(0) {}
explicit MallocedBuffer(size_t size) : data(Malloc<T>(size)), size(size) {}
Expand Down

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