refactor: extract instruction handlers for basics programs

Move instruction handlers into src/instructions/ directory following
Anchor 1.0 conventions for: counter, lever, anchor-realloc, transfer-sol.

Each handler is now a separate file with its own Accounts struct,
and lib.rs delegates to the instruction modules.

Author: mikemaccana-edwardbot

basics/counter/anchor/programs/counter_anchor/src/instructions/increment.rs

@@ -0,0 +1,14 @@
+use anchor_lang::prelude::*;
+
+use crate::Counter;
+
+#[derive(Accounts)]
+pub struct Increment<'info> {
+    #[account(mut)]
+    pub counter: Account<'info, Counter>,
+}
+
+pub fn handler(context: Context<Increment>) -> Result<()> {
+    context.accounts.counter.count = context.accounts.counter.count.checked_add(1).unwrap();
+    Ok(())
+}

basics/counter/anchor/programs/counter_anchor/src/instructions/initialize_counter.rs

@@ -0,0 +1,21 @@
+use anchor_lang::prelude::*;
+
+use crate::Counter;
+
+#[derive(Accounts)]
+pub struct InitializeCounter<'info> {
+    #[account(mut)]
+    pub payer: Signer<'info>,
+
+    #[account(
+        init,
+        space = 8 + Counter::INIT_SPACE,
+        payer = payer
+    )]
+    pub counter: Account<'info, Counter>,
+    pub system_program: Program<'info, System>,
+}
+
+pub fn handler(_context: Context<InitializeCounter>) -> Result<()> {
+    Ok(())
+}

basics/counter/anchor/programs/counter_anchor/src/instructions/mod.rs

@@ -0,0 +1,5 @@
+pub mod increment;
+pub mod initialize_counter;
+
+pub use increment::*;
+pub use initialize_counter::*;

basics/counter/anchor/programs/counter_anchor/src/lib.rs

@@ -1,41 +1,23 @@
 use anchor_lang::prelude::*;
 
+mod instructions;
+use instructions::*;
+
 declare_id!("BmDHboaj1kBUoinJKKSRqKfMeRKJqQqEbUj1VgzeQe4A");
 
 #[program]
 pub mod counter_anchor {
     use super::*;
 
-    pub fn initialize_counter(_context: Context<InitializeCounter>) -> Result<()> {
-        Ok(())
+    pub fn initialize_counter(context: Context<InitializeCounter>) -> Result<()> {
+        instructions::initialize_counter::handler(context)
     }
 
     pub fn increment(context: Context<Increment>) -> Result<()> {
-        context.accounts.counter.count = context.accounts.counter.count.checked_add(1).unwrap();
-        Ok(())
+        instructions::increment::handler(context)
     }
 }
 
-#[derive(Accounts)]
-pub struct InitializeCounter<'info> {
-    #[account(mut)]
-    pub payer: Signer<'info>,
-
-    #[account(
-        init,
-        space = 8 + Counter::INIT_SPACE,
-        payer = payer
-    )]
-    pub counter: Account<'info, Counter>,
-    pub system_program: Program<'info, System>,
-}
-
-#[derive(Accounts)]
-pub struct Increment<'info> {
-    #[account(mut)]
-    pub counter: Account<'info, Counter>,
-}
-
 #[account]
 #[derive(InitSpace)]
 pub struct Counter {

basics/cross-program-invocation/anchor/programs/lever/src/instructions/initialize.rs

@@ -0,0 +1,16 @@
+use anchor_lang::prelude::*;
+
+use crate::PowerStatus;
+
+#[derive(Accounts)]
+pub struct InitializeLever<'info> {
+    #[account(init, payer = user, space = PowerStatus::DISCRIMINATOR.len() + PowerStatus::INIT_SPACE)]
+    pub power: Account<'info, PowerStatus>,
+    #[account(mut)]
+    pub user: Signer<'info>,
+    pub system_program: Program<'info, System>,
+}
+
+pub fn handler(_context: Context<InitializeLever>) -> Result<()> {
+    Ok(())
+}

basics/cross-program-invocation/anchor/programs/lever/src/instructions/mod.rs

@@ -0,0 +1,5 @@
+pub mod initialize;
+pub mod switch_power;
+
+pub use initialize::*;
+pub use switch_power::*;

basics/cross-program-invocation/anchor/programs/lever/src/instructions/switch_power.rs

@@ -0,0 +1,23 @@
+use anchor_lang::prelude::*;
+
+use crate::PowerStatus;
+
+#[derive(Accounts)]
+pub struct SetPowerStatus<'info> {
+    #[account(mut)]
+    pub power: Account<'info, PowerStatus>,
+}
+
+pub fn handler(context: Context<SetPowerStatus>, name: String) -> Result<()> {
+    let power = &mut context.accounts.power;
+    power.is_on = !power.is_on;
+
+    msg!("{} is pulling the power switch!", &name);
+
+    match power.is_on {
+        true => msg!("The power is now on."),
+        false => msg!("The power is now off!"),
+    };
+
+    Ok(())
+}

basics/cross-program-invocation/anchor/programs/lever/src/lib.rs

@@ -1,45 +1,23 @@
 use anchor_lang::prelude::*;
 
+mod instructions;
+use instructions::*;
+
 declare_id!("E64FVeubGC4NPNF2UBJYX4AkrVowf74fRJD9q6YhwstN");
 
 #[program]
 pub mod lever {
     use super::*;
 
-    pub fn initialize(_context: Context<InitializeLever>) -> Result<()> {
-        Ok(())
+    pub fn initialize(context: Context<InitializeLever>) -> Result<()> {
+        instructions::initialize::handler(context)
     }
 
     pub fn switch_power(context: Context<SetPowerStatus>, name: String) -> Result<()> {
-        let power = &mut context.accounts.power;
-        power.is_on = !power.is_on;
-
-        msg!("{} is pulling the power switch!", &name);
-
-        match power.is_on {
-            true => msg!("The power is now on."),
-            false => msg!("The power is now off!"),
-        };
-
-        Ok(())
+        instructions::switch_power::handler(context, name)
     }
 }
 
-#[derive(Accounts)]
-pub struct InitializeLever<'info> {
-    #[account(init, payer = user, space = PowerStatus::DISCRIMINATOR.len() + PowerStatus::INIT_SPACE)]
-    pub power: Account<'info, PowerStatus>,
-    #[account(mut)]
-    pub user: Signer<'info>,
-    pub system_program: Program<'info, System>,
-}
-
-#[derive(Accounts)]
-pub struct SetPowerStatus<'info> {
-    #[account(mut)]
-    pub power: Account<'info, PowerStatus>,
-}
-
 #[account]
 #[derive(InitSpace)]
 pub struct PowerStatus {

basics/realloc/anchor/programs/anchor-realloc/src/instructions/initialize.rs

@@ -0,0 +1,23 @@
+use anchor_lang::prelude::*;
+
+use crate::Message;
+
+#[derive(Accounts)]
+#[instruction(input: String)]
+pub struct Initialize<'info> {
+    #[account(mut)]
+    pub payer: Signer<'info>,
+
+    #[account(
+        init,
+        payer = payer,
+        space = Message::required_space(input.len()),
+    )]
+    pub message_account: Account<'info, Message>,
+    pub system_program: Program<'info, System>,
+}
+
+pub fn handler(context: Context<Initialize>, input: String) -> Result<()> {
+    context.accounts.message_account.message = input;
+    Ok(())
+}

basics/realloc/anchor/programs/anchor-realloc/src/instructions/mod.rs

@@ -0,0 +1,5 @@
+pub mod initialize;
+pub mod update;
+
+pub use initialize::*;
+pub use update::*;