Check (and display) app vs partition size before flashing

espflash/src/error.rs

@@ -38,6 +38,8 @@ pub enum Error {
         help("Either build the binary to be all in ram or remove the `--ram` option to load the image to flash")
     )]
     ElfNotRamLoadable,
+    #[error("Supplied elf image is too big and doesn't fit configured app partition")]
+    ElfTooBig,
     #[error("The bootloader returned an error")]
     #[diagnostic(transparent)]
     RomError(#[from] RomError),

espflash/src/image_format/esp32bootloader.rs

@@ -13,7 +13,7 @@ use crate::{
     error::{Error, FlashDetectError},
     flasher::FlashSize,
     image_format::{EspCommonHeader, ImageFormat, SegmentHeader, ESP_MAGIC, WP_PIN_DISABLED},
-    partition_table::{CoreType, Type},
+    partition_table::{CoreType, Partition, Type},
     Chip, PartitionTable,
 };
 
@@ -161,6 +161,8 @@ impl<'a> Esp32BootloaderFormat<'a> {
             .or_else(|| partition_table.find_by_type(Type::CoreType(CoreType::App)))
             .unwrap();
 
+        Self::check_partition_stats(factory_partition, &data)?;
+
         let flash_segment = RomSegment {
             addr: factory_partition.offset(),
             data: Cow::Owned(data),
@@ -173,6 +175,22 @@ impl<'a> Esp32BootloaderFormat<'a> {
             flash_segment,
         })
     }
+
+    fn check_partition_stats(part: &Partition, data: &Vec<u8>) -> Result<(), Error> {
+        let perc = data.len() as f32 / part.size as f32 * 100.0;
+        println!(
+            "App/part. size:    {}/{} bytes, {:.2}%",
+            data.len(),
+            part.size,
+            perc
+        );
+
+        if perc > 100.0 {
+            return Err(Error::ElfTooBig);
+        }
+
+        Ok(())
+    }
 }
 
 impl<'a> ImageFormat<'a> for Esp32BootloaderFormat<'a> {

espflash/src/partition_table.rs

@@ -572,7 +572,7 @@ pub struct Partition {
     ty: Type,
     sub_type: SubType,
     offset: u32,
-    size: u32,
+    pub(crate) size: u32,
     #[br(count = 16)]
     #[br(map = |s: Vec<u8>| String::from_utf8_lossy(&s).trim_matches(char::from(0)).to_string())]
     name: String,