From fc85f8a47d4821575c13a1d5df4638f9cea934d2 Mon Sep 17 00:00:00 2001
From: 0xFEEDC0DE64 <daniel@brunner.ninja>
Date: Thu, 18 Feb 2021 22:43:17 +0100
Subject: [PATCH 1/2] esp_log: Implemented esp_log_level_get(TAG)

Closes https://github.com/espressif/esp-idf/pull/6573
---
 components/log/include/esp_log.h | 10 ++++++++++
 components/log/log.c             | 19 +++++++++++++++++++
 2 files changed, 29 insertions(+)

diff --git a/components/log/include/esp_log.h b/components/log/include/esp_log.h
index 02f7d167fe..d46e8068b1 100644
--- a/components/log/include/esp_log.h
+++ b/components/log/include/esp_log.h
@@ -71,6 +71,16 @@ extern esp_log_level_t esp_log_default_level;
  */
 void esp_log_level_set(const char* tag, esp_log_level_t level);
 
+/**
+ * @brief Get log level for given tag, can be used to avoid expensive log statements
+ *
+ * @param tag Tag of the log to query current level. Must be a non-NULL zero terminated
+ *            string.
+ *
+ * @return The current log level for the given tag
+ */
+esp_log_level_t esp_log_level_get(const char* tag);
+
 /**
  * @brief Set function used to output log entries
  *
diff --git a/components/log/log.c b/components/log/log.c
index 9af956516c..84b36638da 100644
--- a/components/log/log.c
+++ b/components/log/log.c
@@ -141,6 +141,25 @@ void esp_log_level_set(const char *tag, esp_log_level_t level)
     esp_log_impl_unlock();
 }
 
+esp_log_level_t esp_log_level_get(const char* tag)
+{
+    esp_log_impl_lock();
+    esp_log_level_t level_for_tag;
+    // Look for the tag in cache first, then in the linked list of all tags
+    if (!get_cached_log_level(tag, &level_for_tag)) {
+        if (!get_uncached_log_level(tag, &level_for_tag)) {
+            level_for_tag = esp_log_default_level;
+        }
+        add_to_cache(tag, level_for_tag);
+#ifdef LOG_BUILTIN_CHECKS
+        ++s_log_cache_misses;
+#endif
+    }
+    esp_log_impl_unlock();
+
+    return level_for_tag;
+}
+
 void clear_log_level_list(void)
 {
     uncached_tag_entry_t *it;

From 6c44fe291cc054620fef80956958965ca6055202 Mon Sep 17 00:00:00 2001
From: Angus Gratton <angus@espressif.com>
Date: Mon, 7 Jun 2021 17:11:16 +1000
Subject: [PATCH 2/2] esp_log: Refactor esp_log_level_get() into a common
 static function

Removes duplicate code for a small runtime & size overhead if
esp_log_level_get() is not called in the firmware.

Follow-up to https://github.com/espressif/esp-idf/pull/6573
---
 components/log/log.c | 27 +++++++++++++--------------
 1 file changed, 13 insertions(+), 14 deletions(-)

diff --git a/components/log/log.c b/components/log/log.c
index 84b36638da..4ac47c5b14 100644
--- a/components/log/log.c
+++ b/components/log/log.c
@@ -141,9 +141,13 @@ void esp_log_level_set(const char *tag, esp_log_level_t level)
     esp_log_impl_unlock();
 }
 
-esp_log_level_t esp_log_level_get(const char* tag)
+
+/* Common code for getting the log level from cache, esp_log_impl_lock()
+   should be called before calling this function. The function unlocks,
+   as indicated in the name.
+*/
+static esp_log_level_t s_log_level_get_and_unlock(const char *tag)
 {
-    esp_log_impl_lock();
     esp_log_level_t level_for_tag;
     // Look for the tag in cache first, then in the linked list of all tags
     if (!get_cached_log_level(tag, &level_for_tag)) {
@@ -160,6 +164,12 @@ esp_log_level_t esp_log_level_get(const char* tag)
     return level_for_tag;
 }
 
+esp_log_level_t esp_log_level_get(const char *tag)
+{
+    esp_log_impl_lock();
+    return s_log_level_get_and_unlock(tag);
+}
+
 void clear_log_level_list(void)
 {
     uncached_tag_entry_t *it;
@@ -182,18 +192,7 @@ void esp_log_writev(esp_log_level_t level,
     if (!esp_log_impl_lock_timeout()) {
         return;
     }
-    esp_log_level_t level_for_tag;
-    // Look for the tag in cache first, then in the linked list of all tags
-    if (!get_cached_log_level(tag, &level_for_tag)) {
-        if (!get_uncached_log_level(tag, &level_for_tag)) {
-            level_for_tag = esp_log_default_level;
-        }
-        add_to_cache(tag, level_for_tag);
-#ifdef LOG_BUILTIN_CHECKS
-        ++s_log_cache_misses;
-#endif
-    }
-    esp_log_impl_unlock();
+    esp_log_level_t level_for_tag = s_log_level_get_and_unlock(tag);
     if (!should_output(level, level_for_tag)) {
         return;
     }