fuels_programs/

executable.rs

use fuels_core::{
    types::{
        errors::Result,
        transaction_builders::{Blob, BlobTransactionBuilder},
    },
    Configurables,
};

use crate::{
    assembly::script_and_predicate_loader::{extract_data_offset, LoaderCode},
    DEFAULT_MAX_FEE_ESTIMATION_TOLERANCE,
};

/// This struct represents a standard executable with its associated bytecode and configurables.
#[derive(Debug, Clone, PartialEq)]
pub struct Regular {
    code: Vec<u8>,
    configurables: Configurables,
}

impl Regular {
    pub fn new(code: Vec<u8>, configurables: Configurables) -> Self {
        Self {
            code,
            configurables,
        }
    }
}

/// Used to transform Script or Predicate code into a loader variant, where the code is uploaded as
/// a blob and the binary itself is substituted with code that will load the blob code and apply
/// the given configurables to the Script/Predicate.
#[derive(Debug, Clone, PartialEq)]
pub struct Executable<State> {
    state: State,
}

impl Executable<Regular> {
    pub fn from_bytes(code: Vec<u8>) -> Self {
        Executable {
            state: Regular::new(code, Default::default()),
        }
    }

    /// Loads an `Executable<Regular>` from a file at the given path.
    ///
    /// # Parameters
    ///
    /// - `path`: The file path to load the executable from.
    ///
    /// # Returns
    ///
    /// A `Result` containing the `Executable<Regular>` or an error if loading fails.
    pub fn load_from(path: &str) -> Result<Executable<Regular>> {
        let code = std::fs::read(path)?;

        Ok(Executable {
            state: Regular::new(code, Default::default()),
        })
    }

    pub fn with_configurables(self, configurables: impl Into<Configurables>) -> Self {
        Executable {
            state: Regular {
                configurables: configurables.into(),
                ..self.state
            },
        }
    }

    pub fn data_offset_in_code(&self) -> Result<usize> {
        extract_data_offset(&self.state.code)
    }

    /// Returns the code of the executable with configurables applied.
    ///
    /// # Returns
    ///
    /// The bytecode of the executable with configurables updated.
    pub fn code(&self) -> Vec<u8> {
        let mut code = self.state.code.clone();
        self.state.configurables.update_constants_in(&mut code);
        code
    }

    /// Converts the `Executable<Regular>` into an `Executable<Loader>`.
    ///
    /// # Returns
    ///
    /// A `Result` containing the `Executable<Loader>` or an error if loader code cannot be
    /// generated for the given binary.
    pub fn convert_to_loader(self) -> Result<Executable<Loader>> {
        validate_loader_can_be_made_from_code(
            self.state.code.clone(),
            self.state.configurables.clone(),
        )?;

        Ok(Executable {
            state: Loader {
                code: self.state.code,
                configurables: self.state.configurables,
            },
        })
    }
}

pub struct Loader {
    code: Vec<u8>,
    configurables: Configurables,
}

impl Executable<Loader> {
    pub fn with_configurables(self, configurables: impl Into<Configurables>) -> Self {
        Executable {
            state: Loader {
                configurables: configurables.into(),
                ..self.state
            },
        }
    }

    pub fn data_offset_in_code(&self) -> usize {
        self.loader_code().data_section_offset()
    }

    fn loader_code(&self) -> LoaderCode {
        let mut code = self.state.code.clone();

        self.state.configurables.update_constants_in(&mut code);

        LoaderCode::from_normal_binary(code)
            .expect("checked before turning into a Executable<Loader>")
    }

    /// Returns the code of the loader executable with configurables applied.
    pub fn code(&self) -> Vec<u8> {
        self.loader_code().as_bytes().to_vec()
    }

    /// A Blob containing the original executable code minus the data section.
    pub fn blob(&self) -> Blob {
        // we don't apply configurables because they touch the data section which isn't part of the
        // blob
        LoaderCode::extract_blob(&self.state.code)
            .expect("checked before turning into a Executable<Loader>")
    }

    /// Uploads a blob containing the original executable code minus the data section.
    pub async fn upload_blob(&self, account: impl fuels_accounts::Account) -> Result<()> {
        let blob = self.blob();
        let provider = account.try_provider()?;

        if provider.blob_exists(blob.id()).await? {
            return Ok(());
        }

        let mut tb = BlobTransactionBuilder::default()
            .with_blob(self.blob())
            .with_max_fee_estimation_tolerance(DEFAULT_MAX_FEE_ESTIMATION_TOLERANCE);

        account.adjust_for_fee(&mut tb, 0).await?;

        account.add_witnesses(&mut tb)?;

        let tx = tb.build(provider).await?;

        provider
            .send_transaction_and_await_commit(tx)
            .await?
            .check(None)?;

        Ok(())
    }
}

fn validate_loader_can_be_made_from_code(
    mut code: Vec<u8>,
    configurables: Configurables,
) -> Result<()> {
    configurables.update_constants_in(&mut code);

    let _ = LoaderCode::from_normal_binary(code)?;

    Ok(())
}

#[cfg(test)]
mod tests {
    use super::*;
    use fuels_core::Configurables;
    use std::io::Write;
    use tempfile::NamedTempFile;

    #[test]
    fn test_executable_regular_from_bytes() {
        // Given: Some bytecode
        let code = vec![1u8, 2, 3, 4];

        // When: Creating an Executable<Regular> from bytes
        let executable = Executable::<Regular>::from_bytes(code.clone());

        // Then: The executable should have the given code and default configurables
        assert_eq!(executable.state.code, code);
        assert_eq!(executable.state.configurables, Default::default());
    }

    #[test]
    fn test_executable_regular_load_from() {
        // Given: A temporary file containing some bytecode
        let code = vec![5u8, 6, 7, 8];
        let mut temp_file = NamedTempFile::new().expect("Failed to create temp file");
        temp_file
            .write_all(&code)
            .expect("Failed to write to temp file");
        let path = temp_file.path().to_str().unwrap();

        // When: Loading an Executable<Regular> from the file
        let executable_result = Executable::<Regular>::load_from(path);

        // Then: The executable should be created successfully with the correct code
        assert!(executable_result.is_ok());
        let executable = executable_result.unwrap();
        assert_eq!(executable.state.code, code);
        assert_eq!(executable.state.configurables, Default::default());
    }

    #[test]
    fn test_executable_regular_load_from_invalid_path() {
        // Given: An invalid file path
        let invalid_path = "/nonexistent/path/to/file";

        // When: Attempting to load an Executable<Regular> from the invalid path
        let executable_result = Executable::<Regular>::load_from(invalid_path);

        // Then: The operation should fail with an error
        assert!(executable_result.is_err());
    }

    #[test]
    fn test_executable_regular_with_configurables() {
        // Given: An Executable<Regular> and some configurables
        let code = vec![1u8, 2, 3, 4];
        let executable = Executable::<Regular>::from_bytes(code);
        let configurables = Configurables::new(vec![(2, vec![1])]);

        // When: Setting new configurables
        let new_executable = executable.with_configurables(configurables.clone());

        // Then: The executable should have the new configurables
        assert_eq!(new_executable.state.configurables, configurables);
    }

    #[test]
    fn test_executable_regular_code() {
        // Given: An Executable<Regular> with some code and configurables
        let code = vec![1u8, 2, 3, 4];
        let configurables = Configurables::new(vec![(1, vec![1])]);
        let executable =
            Executable::<Regular>::from_bytes(code.clone()).with_configurables(configurables);

        // When: Retrieving the code after applying configurables
        let modified_code = executable.code();

        assert_eq!(modified_code, vec![1, 1, 3, 4]);
    }

    #[test]
    fn test_loader_extracts_code_and_data_section_correctly() {
        // Given: An Executable<Regular> with valid code
        let padding = vec![0; 8];
        let offset = 20u64.to_be_bytes().to_vec();
        let some_random_instruction = vec![1, 2, 3, 4];
        let data_section = vec![5, 6, 7, 8];
        let code = [
            padding.clone(),
            offset.clone(),
            some_random_instruction.clone(),
            data_section,
        ]
        .concat();
        let executable = Executable::<Regular>::from_bytes(code.clone());

        // When: Converting to a loader
        let loader = executable.convert_to_loader().unwrap();

        let blob = loader.blob();
        let data_stripped_code = [padding, offset, some_random_instruction].concat();
        assert_eq!(blob.as_ref(), data_stripped_code);

        let loader_code = loader.code();
        assert_eq!(
            loader_code,
            LoaderCode::from_normal_binary(code).unwrap().as_bytes()
        )
    }

    #[test]
    fn test_executable_regular_convert_to_loader_with_invalid_code() {
        // Given: An Executable<Regular> with invalid code (too short)
        let code = vec![1u8, 2]; // Insufficient length for a valid data offset
        let executable = Executable::<Regular>::from_bytes(code);

        // When: Attempting to convert to a loader
        let result = executable.convert_to_loader();

        // Then: The conversion should fail with an error
        assert!(result.is_err());
    }

    #[test]
    fn executable_with_no_data_section() {
        // to skip over the first 2 half words and skip over the offset itself, basically stating
        // that there is no data section
        let data_section_offset = 16u64;

        let code = [vec![0; 8], data_section_offset.to_be_bytes().to_vec()].concat();

        Executable::from_bytes(code).convert_to_loader().unwrap();
    }
}