extract debug_log into its own static library; expose log_view iterator instead of raw ring_buffer

CMakeLists.txt

@@ -1,6 +1,7 @@
 cmake_minimum_required(VERSION 3.13)
 
 add_subdirectory(w6300)
+add_subdirectory(debug_log)
 
 add_library(limen STATIC
     src/arp.cpp
@@ -23,6 +24,7 @@ target_compile_options(limen PRIVATE -Wall -Wextra -Wno-unused-parameter)
 
 target_link_libraries(limen PUBLIC
     w6300
+    debug_log
     pico_stdlib
     pico_sha256
     pico_unique_id

debug_log/CMakeLists.txt

@@ -0,0 +1,7 @@
+add_library(debug_log STATIC debug_log.cpp)
+
+target_include_directories(debug_log PUBLIC ${CMAKE_CURRENT_SOURCE_DIR})
+
+target_compile_options(debug_log PRIVATE -Wall -Wextra -Wno-unused-parameter)
+
+target_link_libraries(debug_log PUBLIC pico_stdlib)

debug_log/debug_log.cpp

@@ -0,0 +1,28 @@
+#include "debug_log.h"
+#include <cstdarg>
+#include <cstdio>
+#include "ring_buffer.h"
+
+namespace {
+
+constexpr uint16_t LOG_CAP = 32;
+ring_buffer<log_entry, LOG_CAP> buf;
+
+} // namespace
+
+void dlog(std::string_view msg) {
+    buf.push_overwrite(log_entry{static_cast<uint32_t>(time_us_32()), std::string(msg)});
+}
+
+void dlogf(const char* fmt, ...) {
+    char b[128];
+    va_list args;
+    va_start(args, fmt);
+    vsnprintf(b, sizeof(b), fmt, args);
+    va_end(args);
+    dlog(b);
+}
+
+log_view log_entries() {
+    return log_view{buf.data.data(), buf.head, LOG_CAP, buf.used()};
+}

debug_log/debug_log.h

@@ -0,0 +1,52 @@
+#pragma once
+#include <cstdint>
+#include <string>
+#include <string_view>
+#include "pico/time.h"
+
+struct log_entry {
+    uint32_t timestamp_us;
+    std::string message;
+};
+
+class log_iterator {
+    const log_entry* data;
+    uint16_t base;
+    uint16_t cap;
+    uint16_t pos;
+public:
+    log_iterator(const log_entry* d, uint16_t b, uint16_t c, uint16_t p)
+        : data(d), base(b), cap(c), pos(p) {}
+    const log_entry& operator*() const { return data[(base + pos) % cap]; }
+    log_iterator& operator++() { ++pos; return *this; }
+    bool operator!=(const log_iterator& o) const { return pos != o.pos; }
+};
+
+class log_view {
+    const log_entry* data;
+    uint16_t base;
+    uint16_t cap;
+    uint16_t count;
+public:
+    log_view(const log_entry* d, uint16_t b, uint16_t c, uint16_t n)
+        : data(d), base(b), cap(c), count(n) {}
+    log_iterator begin() const { return {data, base, cap, 0}; }
+    log_iterator end() const { return {data, base, cap, count}; }
+};
+
+log_view log_entries();
+
+void dlog(std::string_view msg);
+
+__attribute__((format(printf, 1, 2)))
+void dlogf(const char* fmt, ...);
+
+template <typename F>
+inline void dlog_if_slow(std::string_view label, uint32_t threshold_us, F&& fn) {
+    uint32_t t0 = time_us_32();
+    fn();
+    uint32_t elapsed = time_us_32() - t0;
+    if (elapsed > threshold_us) {
+        dlogf("%.*s %luus", static_cast<int>(label.size()), label.data(), static_cast<unsigned long>(elapsed));
+    }
+}

include/debug_log.h

@@ -1,39 +0,0 @@
-#pragma once
-#include <cstdarg>
-#include <cstdio>
-#include <string>
-#include <string_view>
-#include <vector>
-#include "pico/time.h"
-#include "ring_buffer.h"
-
-struct log_entry {
-    uint32_t timestamp_us;
-    std::string message;
-};
-
-inline ring_buffer<log_entry, 32> g_debug_log;
-
-inline void dlog(std::string_view msg) {
-    g_debug_log.push_overwrite(log_entry{static_cast<uint32_t>(time_us_32()), std::string(msg)});
-}
-
-__attribute__((format(printf, 1, 2)))
-inline void dlogf(const char* fmt, ...) {
-    char buf[128];
-    va_list args;
-    va_start(args, fmt);
-    vsnprintf(buf, sizeof(buf), fmt, args);
-    va_end(args);
-    dlog(buf);
-}
-
-template <typename F>
-inline void dlog_if_slow(std::string_view label, uint32_t threshold_us, F&& fn) {
-    uint32_t t0 = time_us_32();
-    fn();
-    uint32_t elapsed = time_us_32() - t0;
-    if (elapsed > threshold_us)
-        dlogf("%.*s %luus", static_cast<int>(label.size()), label.data(), static_cast<unsigned long>(elapsed));
-}
-

src/handlers.cpp

@@ -45,8 +45,9 @@ std::optional<ResponseInfo> handle_info(const responder&, const RequestInfo&) {
 
 std::optional<ResponseLog> handle_log(const responder&, const RequestLog&) {
     ResponseLog resp;
-    for (auto& e : g_debug_log)
+    for (auto& e : log_entries()) {
         resp.entries.push_back(LogEntry{e.timestamp_us, e.message});
+    }
     return resp;
 }