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      1 // Copyright 2014 The Chromium Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 // This file contains types and constants/macros common to different Mojo system
      6 // APIs.
      7 //
      8 // Note: This header should be compilable as C.
      9 
     10 #ifndef MOJO_PUBLIC_C_SYSTEM_TYPES_H_
     11 #define MOJO_PUBLIC_C_SYSTEM_TYPES_H_
     12 
     13 #include <stdint.h>
     14 
     15 #include "mojo/public/c/system/macros.h"
     16 
     17 // |MojoTimeTicks|: A time delta, in microseconds, the meaning of which is
     18 // source-dependent.
     19 
     20 typedef int64_t MojoTimeTicks;
     21 
     22 // |MojoHandle|: Handles to Mojo objects.
     23 //   |MOJO_HANDLE_INVALID| - A value that is never a valid handle.
     24 
     25 typedef uint32_t MojoHandle;
     26 
     27 #ifdef __cplusplus
     28 const MojoHandle MOJO_HANDLE_INVALID = 0;
     29 #else
     30 #define MOJO_HANDLE_INVALID ((MojoHandle)0)
     31 #endif
     32 
     33 // |MojoResult|: Result codes for Mojo operations. The only success code is zero
     34 // (|MOJO_RESULT_OK|); all non-zero values should be considered as error/failure
     35 // codes (even if the value is not recognized).
     36 //   |MOJO_RESULT_OK| - Not an error; returned on success.
     37 //   |MOJO_RESULT_CANCELLED| - Operation was cancelled, typically by the caller.
     38 //   |MOJO_RESULT_UNKNOWN| - Unknown error (e.g., if not enough information is
     39 //       available for a more specific error).
     40 //   |MOJO_RESULT_INVALID_ARGUMENT| - Caller specified an invalid argument. This
     41 //       differs from |MOJO_RESULT_FAILED_PRECONDITION| in that the former
     42 //       indicates arguments that are invalid regardless of the state of the
     43 //       system.
     44 //   |MOJO_RESULT_DEADLINE_EXCEEDED| - Deadline expired before the operation
     45 //       could complete.
     46 //   |MOJO_RESULT_NOT_FOUND| - Some requested entity was not found (i.e., does
     47 //       not exist).
     48 //   |MOJO_RESULT_ALREADY_EXISTS| - Some entity or condition that we attempted
     49 //       to create already exists.
     50 //   |MOJO_RESULT_PERMISSION_DENIED| - The caller does not have permission to
     51 //       for the operation (use |MOJO_RESULT_RESOURCE_EXHAUSTED| for rejections
     52 //       caused by exhausting some resource instead).
     53 //   |MOJO_RESULT_RESOURCE_EXHAUSTED| - Some resource required for the call
     54 //       (possibly some quota) has been exhausted.
     55 //   |MOJO_RESULT_FAILED_PRECONDITION| - The system is not in a state required
     56 //       for the operation (use this if the caller must do something to rectify
     57 //       the state before retrying).
     58 //   |MOJO_RESULT_ABORTED| - The operation was aborted by the system, possibly
     59 //       due to a concurrency issue (use this if the caller may retry at a
     60 //       higher level).
     61 //   |MOJO_RESULT_OUT_OF_RANGE| - The operation was attempted past the valid
     62 //       range. Unlike |MOJO_RESULT_INVALID_ARGUMENT|, this indicates that the
     63 //       operation may be/become valid depending on the system state. (This
     64 //       error is similar to |MOJO_RESULT_FAILED_PRECONDITION|, but is more
     65 //       specific.)
     66 //   |MOJO_RESULT_UNIMPLEMENTED| - The operation is not implemented, supported,
     67 //       or enabled.
     68 //   |MOJO_RESULT_INTERNAL| - Internal error: this should never happen and
     69 //       indicates that some invariant expected by the system has been broken.
     70 //   |MOJO_RESULT_UNAVAILABLE| - The operation is (temporarily) currently
     71 //       unavailable. The caller may simply retry the operation (possibly with a
     72 //       backoff).
     73 //   |MOJO_RESULT_DATA_LOSS| - Unrecoverable data loss or corruption.
     74 //   |MOJO_RESULT_BUSY| - One of the resources involved is currently being used
     75 //       (possibly on another thread) in a way that prevents the current
     76 //       operation from proceeding, e.g., if the other operation may result in
     77 //       the resource being invalidated.
     78 //   |MOJO_RESULT_SHOULD_WAIT| - The request cannot currently be completed
     79 //       (e.g., if the data requested is not yet available). The caller should
     80 //       wait for it to be feasible using a trap.
     81 //
     82 // The codes from |MOJO_RESULT_OK| to |MOJO_RESULT_DATA_LOSS| come from
     83 // Google3's canonical error codes.
     84 
     85 typedef uint32_t MojoResult;
     86 
     87 #ifdef __cplusplus
     88 const MojoResult MOJO_RESULT_OK = 0;
     89 const MojoResult MOJO_RESULT_CANCELLED = 1;
     90 const MojoResult MOJO_RESULT_UNKNOWN = 2;
     91 const MojoResult MOJO_RESULT_INVALID_ARGUMENT = 3;
     92 const MojoResult MOJO_RESULT_DEADLINE_EXCEEDED = 4;
     93 const MojoResult MOJO_RESULT_NOT_FOUND = 5;
     94 const MojoResult MOJO_RESULT_ALREADY_EXISTS = 6;
     95 const MojoResult MOJO_RESULT_PERMISSION_DENIED = 7;
     96 const MojoResult MOJO_RESULT_RESOURCE_EXHAUSTED = 8;
     97 const MojoResult MOJO_RESULT_FAILED_PRECONDITION = 9;
     98 const MojoResult MOJO_RESULT_ABORTED = 10;
     99 const MojoResult MOJO_RESULT_OUT_OF_RANGE = 11;
    100 const MojoResult MOJO_RESULT_UNIMPLEMENTED = 12;
    101 const MojoResult MOJO_RESULT_INTERNAL = 13;
    102 const MojoResult MOJO_RESULT_UNAVAILABLE = 14;
    103 const MojoResult MOJO_RESULT_DATA_LOSS = 15;
    104 const MojoResult MOJO_RESULT_BUSY = 16;
    105 const MojoResult MOJO_RESULT_SHOULD_WAIT = 17;
    106 #else
    107 #define MOJO_RESULT_OK ((MojoResult)0)
    108 #define MOJO_RESULT_CANCELLED ((MojoResult)1)
    109 #define MOJO_RESULT_UNKNOWN ((MojoResult)2)
    110 #define MOJO_RESULT_INVALID_ARGUMENT ((MojoResult)3)
    111 #define MOJO_RESULT_DEADLINE_EXCEEDED ((MojoResult)4)
    112 #define MOJO_RESULT_NOT_FOUND ((MojoResult)5)
    113 #define MOJO_RESULT_ALREADY_EXISTS ((MojoResult)6)
    114 #define MOJO_RESULT_PERMISSION_DENIED ((MojoResult)7)
    115 #define MOJO_RESULT_RESOURCE_EXHAUSTED ((MojoResult)8)
    116 #define MOJO_RESULT_FAILED_PRECONDITION ((MojoResult)9)
    117 #define MOJO_RESULT_ABORTED ((MojoResult)10)
    118 #define MOJO_RESULT_OUT_OF_RANGE ((MojoResult)11)
    119 #define MOJO_RESULT_UNIMPLEMENTED ((MojoResult)12)
    120 #define MOJO_RESULT_INTERNAL ((MojoResult)13)
    121 #define MOJO_RESULT_UNAVAILABLE ((MojoResult)14)
    122 #define MOJO_RESULT_DATA_LOSS ((MojoResult)15)
    123 #define MOJO_RESULT_BUSY ((MojoResult)16)
    124 #define MOJO_RESULT_SHOULD_WAIT ((MojoResult)17)
    125 #endif
    126 
    127 // |MojoDeadline|: Used to specify deadlines (timeouts), in microseconds (except
    128 // for |MOJO_DEADLINE_INDEFINITE|).
    129 //   |MOJO_DEADLINE_INDEFINITE| - Used to indicate "forever".
    130 
    131 typedef uint64_t MojoDeadline;
    132 
    133 #ifdef __cplusplus
    134 const MojoDeadline MOJO_DEADLINE_INDEFINITE = static_cast<MojoDeadline>(-1);
    135 #else
    136 #define MOJO_DEADLINE_INDEFINITE ((MojoDeadline)-1)
    137 #endif
    138 
    139 // Flags passed to |MojoInitialize()| via |MojoInitializeOptions|.
    140 typedef uint32_t MojoInitializeFlags;
    141 
    142 // No flags.
    143 #define MOJO_INITIALIZE_FLAG_NONE ((MojoInitializeFlags)0)
    144 
    145 // Options passed to |MojoInitialize()|.
    146 struct MOJO_ALIGNAS(8) MojoInitializeOptions {
    147   // The size of this structure, used for versioning.
    148   uint32_t struct_size;
    149 
    150   // See |MojoInitializeFlags|.
    151   MojoInitializeFlags flags;
    152 
    153   // Address and length of the UTF8-encoded path of a mojo_core shared library
    154   // to load. If the |mojo_core_path| is null then |mojo_core_path_length| is
    155   // ignored and Mojo will fall back first onto the |MOJO_CORE_LIBRARY_PATH|
    156   // environment variable, and then onto the current working directory.
    157   MOJO_POINTER_FIELD(const char*, mojo_core_path);
    158   uint32_t mojo_core_path_length;
    159 };
    160 MOJO_STATIC_ASSERT(sizeof(MojoInitializeOptions) == 24,
    161                    "MojoInitializeOptions has wrong size");
    162 
    163 // |MojoHandleSignals|: Used to specify signals that can be watched for on a
    164 // handle (and which can be triggered), e.g., the ability to read or write to
    165 // the handle.
    166 //   |MOJO_HANDLE_SIGNAL_NONE| - No flags. A registered watch will always fail
    167 //       to arm with |MOJO_RESULT_FAILED_PRECONDITION| when watching for this.
    168 //   |MOJO_HANDLE_SIGNAL_READABLE| - Can read (e.g., a message) from the handle.
    169 //   |MOJO_HANDLE_SIGNAL_WRITABLE| - Can write (e.g., a message) to the handle.
    170 //   |MOJO_HANDLE_SIGNAL_PEER_CLOSED| - The peer handle is closed.
    171 //   |MOJO_HANDLE_SIGNAL_NEW_DATA_READABLE| - Can read data from a data pipe
    172 //       consumer handle (implying MOJO_HANDLE_SIGNAL_READABLE is also set),
    173 //       AND there is some nonzero quantity of new data available on the pipe
    174 //       since the last |MojoReadData()| or |MojoBeginReadData()| call on the
    175 //       handle.
    176 //   |MOJO_HANDLE_SIGNAL_PEER_REMOTE| - The peer handle exists in a remote
    177 //       execution context (e.g. in another process.) Note that this signal is
    178 //       maintained with best effort but may at any time be slightly out of sync
    179 //       with the actual location of the peer handle.
    180 //   |MOJO_HANDLE_SIGNAL_QUOTA_EXCEEDED| - One or more quotas set on the handle
    181 //       is currently exceeded.
    182 
    183 typedef uint32_t MojoHandleSignals;
    184 
    185 #ifdef __cplusplus
    186 const MojoHandleSignals MOJO_HANDLE_SIGNAL_NONE = 0;
    187 const MojoHandleSignals MOJO_HANDLE_SIGNAL_READABLE = 1 << 0;
    188 const MojoHandleSignals MOJO_HANDLE_SIGNAL_WRITABLE = 1 << 1;
    189 const MojoHandleSignals MOJO_HANDLE_SIGNAL_PEER_CLOSED = 1 << 2;
    190 const MojoHandleSignals MOJO_HANDLE_SIGNAL_NEW_DATA_READABLE = 1 << 3;
    191 const MojoHandleSignals MOJO_HANDLE_SIGNAL_PEER_REMOTE = 1 << 4;
    192 const MojoHandleSignals MOJO_HANDLE_SIGNAL_QUOTA_EXCEEDED = 1 << 5;
    193 #else
    194 #define MOJO_HANDLE_SIGNAL_NONE ((MojoHandleSignals)0)
    195 #define MOJO_HANDLE_SIGNAL_READABLE ((MojoHandleSignals)1 << 0)
    196 #define MOJO_HANDLE_SIGNAL_WRITABLE ((MojoHandleSignals)1 << 1)
    197 #define MOJO_HANDLE_SIGNAL_PEER_CLOSED ((MojoHandleSignals)1 << 2)
    198 #define MOJO_HANDLE_SIGNAL_NEW_DATA_READABLE ((MojoHandleSignals)1 << 3);
    199 #define MOJO_HANDLE_SIGNAL_PEER_REMOTE ((MojoHandleSignals)1 << 4);
    200 #define MOJO_HANDLE_SIGNAL_QUOTA_EXCEEDED ((MojoHandleSignals)1 << 5);
    201 #endif
    202 
    203 // |MojoHandleSignalsState|: Returned by watch notification callbacks and
    204 // |MojoQueryHandleSignalsState| functions to indicate the signaling state of
    205 // handles. Members are as follows:
    206 //   - |satisfied signals|: Bitmask of signals that were satisfied at some time
    207 //         before the call returned.
    208 //   - |satisfiable signals|: These are the signals that are possible to
    209 //         satisfy. For example, if the return value was
    210 //         |MOJO_RESULT_FAILED_PRECONDITION|, you can use this field to
    211 //         determine which, if any, of the signals can still be satisfied.
    212 // Note: This struct is not extensible (and only has 32-bit quantities), so it's
    213 // 32-bit-aligned.
    214 MOJO_STATIC_ASSERT(MOJO_ALIGNOF(int32_t) == 4, "int32_t has weird alignment");
    215 struct MOJO_ALIGNAS(4) MojoHandleSignalsState {
    216   MojoHandleSignals satisfied_signals;
    217   MojoHandleSignals satisfiable_signals;
    218 };
    219 MOJO_STATIC_ASSERT(sizeof(MojoHandleSignalsState) == 8,
    220                    "MojoHandleSignalsState has wrong size");
    221 
    222 // TODO(https://crbug.com/819046): Remove these aliases.
    223 #define MOJO_WATCH_CONDITION_SATISFIED MOJO_TRIGGER_CONDITION_SIGNALS_SATISFIED
    224 #define MOJO_WATCH_CONDITION_NOT_SATISFIED \
    225   MOJO_TRIGGER_CONDITION_SIGNALS_UNSATISFIED
    226 
    227 #endif  // MOJO_PUBLIC_C_SYSTEM_TYPES_H_
    228