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https://github.com/tianocore/edk2
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de527ff606
Replace traditional `#ifndef`/`#define`/`#endif` include guards with
`#pragma` once.
`#pragma once` is a widely supported preprocessor directive that
prevents header files from being included multiple times. It is
supported by all toolchains used to build edk2: GCC, Clang/LLVM, and
MSVC.
Compared to macro-based include guards, `#pragma once`:
- Eliminates the risk of macro name collisions or copy/paste errors
where two headers inadvertently use the same guard macro.
- Eliminate inconsistency in the way include guard macros are named
(e.g., some files use `__FILE_H__`, others use `FILE_H_`, etc.).
- Reduces boilerplate (three lines replaced by one).
- Avoids polluting the macro namespace with guard symbols.
- Can improve build times as the preprocessor can skip re-opening the
file entirely, rather than re-reading it to find the matching
`#endif` ("multiple-include optimization").
- Note that some compilers may already optimize traditional include
guards, by recognzining the idiomatic pattern.
This change is made acknowledging that overall portability of the
code will technically be reduced, as `#pragma once` is not part of the
C/C++ standards.
However, this is considered acceptable given:
1. edk2 already defines a subset of supported compilers in
BaseTools/Conf/tools_def.template, all of which have supported
`#pragma once` for over two decades.
2. There have been concerns raised to the project about inconsistent
include guard naming and potential macro collisions.
Approximate compiler support dates:
- MSVC: Supported since Visual C++ 4.2 (1996)
- GCC: Supported since 3.4 (2004)
(http://gnu.ist.utl.pt/software/gcc/gcc-3.4/changes.html)
- Clang (LLVM based): Since initial release in 2007
Signed-off-by: Michael Kubacki <michael.kubacki@microsoft.com>
77 lines
2.9 KiB
C
77 lines
2.9 KiB
C
/** @file
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Copyright (c) 2018, Linaro. All rights reserved.<BR>
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SPDX-License-Identifier: BSD-2-Clause-Patent
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**/
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#pragma once
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//
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// Protocol interface structure
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//
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typedef struct _PLATFORM_BOOT_MANAGER_PROTOCOL PLATFORM_BOOT_MANAGER_PROTOCOL;
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//
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// Function Prototypes
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//
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/*
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Get predefined boot options for platform.
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@param[out] Count The number of elements in each of
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BootOptions and BootKeys. On successful
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return, Count is at least one.
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@param[out] BootOptions An array of platform boot options.
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BootOptions is pool-allocated by
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GET_PLATFORM_BOOT_OPTIONS_AND_KEYS, and
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GET_PLATFORM_BOOT_OPTIONS_AND_KEYS populates
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every element in BootOptions with
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EfiBootManagerInitializeLoadOption().
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BootOptions shall not contain duplicate
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entries. The caller is responsible for
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releasing BootOptions after use with
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EfiBootManagerFreeLoadOptions().
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@param[out] BootKeys A pool-allocated array of platform boot
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hotkeys. For every 0 <= Index < Count, if
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BootOptions[Index] is not to be associated
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with a hotkey, then BootKeys[Index] is
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zero-filled. Otherwise, BootKeys[Index]
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specifies the boot hotkey for
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BootOptions[Index]. BootKeys shall not
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contain duplicate entries (other than
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zero-filled entries). The caller is
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responsible for releasing BootKeys with
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FreePool() after use.
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@retval EFI_SUCCESS Count, BootOptions and BootKeys have
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been set.
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@retval EFI_OUT_OF_RESOURCES Memory allocation failed.
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@retval EFI_UNSUPPORTED The platform doesn't provide boot options
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as a feature.
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@retval EFI_NOT_FOUND The platform could provide boot options
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as a feature, but none have been
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configured.
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@return Error codes propagated from underlying
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functions.
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*/
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typedef
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EFI_STATUS
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(EFIAPI *GET_PLATFORM_BOOT_OPTIONS_AND_KEYS)(
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OUT UINTN *Count,
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OUT EFI_BOOT_MANAGER_LOAD_OPTION **BootOptions,
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OUT EFI_INPUT_KEY **BootKeys
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);
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struct _PLATFORM_BOOT_MANAGER_PROTOCOL {
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GET_PLATFORM_BOOT_OPTIONS_AND_KEYS GetPlatformBootOptionsAndKeys;
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};
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extern EFI_GUID gPlatformBootManagerProtocolGuid;
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