From 048ee6fb94a869626b8f9d13e70a2f9fb98a31c0 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jorge=20Mu=C3=B1oz?= <punkto@gmail.com>
Date: Sat, 1 Jul 2023 13:53:28 +0200
Subject: [PATCH] Add example that uses the C type of NVS API

---
 examples/nvs_get_set_c_style.rs | 78 +++++++++++++++++++++++++++++++++
 1 file changed, 78 insertions(+)
 create mode 100644 examples/nvs_get_set_c_style.rs

diff --git a/examples/nvs_get_set_c_style.rs b/examples/nvs_get_set_c_style.rs
new file mode 100644
index 00000000000..06ea68873dc
--- /dev/null
+++ b/examples/nvs_get_set_c_style.rs
@@ -0,0 +1,78 @@
+//! Updates tags from the NVS (default partition).
+//! 
+//! Note that this module exposes two separate set of APIs:
+//!  * the get_XXX/set_XXX API (where XXX is u8, str, etc.) - this is only for interop with C code that uses the C ESP IDF NVS API as well.
+//!  * the `get_raw`/`set_raw` APIs that take a `&[u8]`. This is the "native" Rust API that implements the `RawStorage` trait from `embedded-svc` and it should be preferred actually, as you can layer on top of it any serde you want.
+//! 
+//! More info reagarding NVS:
+//!   https://docs.espressif.com/projects/esp-idf/en/latest/esp32/api-reference/storage/nvs_flash.html
+
+use esp_idf_sys::{self as _}; // If using the `binstart` feature of `esp-idf-sys`, always keep this module imported
+
+use esp_idf_svc::nvs::*;
+use esp_idf_svc::log::EspLogger;
+use log::info;
+
+
+fn main() -> anyhow::Result<()> {
+    EspLogger::initialize_default();
+
+    let nvs_default_partition: EspNvsPartition<NvsDefault> =
+        EspDefaultNvsPartition::take().unwrap();
+
+    let test_namespace = "test_ns";
+    let mut nvs = match EspNvs::new(nvs_default_partition, test_namespace, true) {
+        Ok(nvs) => {
+            info!("Got namespace {:?} from default partition", test_namespace);
+            nvs
+        }
+        Err(e) => panic!("Could't get namespace {:?}", e),
+    };
+
+    let tag_u8 = "test_u8";
+
+    match nvs.set_u8(tag_u8, 42) {
+        Ok(_) => info!("Tag updated"),
+        // You can find the meaning of the error codes in the output of the error branch in:
+        // https://docs.espressif.com/projects/esp-idf/en/latest/esp32/api-reference/error-codes.html
+        Err(e) => info!("Tag not updated {:?}", e),
+    };
+
+    match nvs.get_u8(tag_u8).unwrap() {
+        Some(v) => info!("{:?} = {:?}", tag_u8, v),
+        None => info!("{:?} not found", tag_u8),
+    };
+
+    let tag_test_str = "test_str";
+    // String values are limited in the IDF to 4000 bytes, but our buffer is shorter.
+    const MAX_STR_LEN: usize = 100;
+
+    let the_str_len: usize = nvs.str_len(tag_test_str).map_or(0, |v| {
+        info!("Got stored string length of {:?}", v);
+        let vv = v.unwrap_or(0);
+        if vv >= MAX_STR_LEN {
+            info!("Too long, trimming");
+            0
+        } else {
+            vv
+        }
+    });
+
+    match the_str_len == 0 {
+        true => info!("{:?} does not seem to exist", tag_test_str),
+        false => {
+            let mut buffer: [u8; MAX_STR_LEN] = [0; MAX_STR_LEN];
+            match nvs.get_str(tag_test_str, &mut buffer).unwrap() {
+                Some(v) => info!("{:?} = {:?}", tag_test_str, v),
+                None => info!("We got nothing from {:?}", tag_test_str),
+            };
+        }
+    };
+
+    match nvs.set_str(tag_test_str, "Hello from the NVS!") {
+        Ok(_) => info!("{:?} updated", tag_test_str),
+        Err(e) => info!("{:?} not updated {:?}", tag_test_str, e),
+    };
+
+    Ok(())
+}
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